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      1 /*
      2  * Copyright (C) 2006 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 import com.android.internal.R;
     20 import com.android.internal.view.menu.MenuBuilder;
     21 
     22 import android.content.Context;
     23 import android.content.res.Configuration;
     24 import android.content.res.Resources;
     25 import android.content.res.TypedArray;
     26 import android.graphics.Bitmap;
     27 import android.graphics.Canvas;
     28 import android.graphics.Interpolator;
     29 import android.graphics.LinearGradient;
     30 import android.graphics.Matrix;
     31 import android.graphics.Paint;
     32 import android.graphics.PixelFormat;
     33 import android.graphics.Point;
     34 import android.graphics.PorterDuff;
     35 import android.graphics.PorterDuffXfermode;
     36 import android.graphics.Rect;
     37 import android.graphics.Region;
     38 import android.graphics.Shader;
     39 import android.graphics.drawable.ColorDrawable;
     40 import android.graphics.drawable.Drawable;
     41 import android.os.Handler;
     42 import android.os.IBinder;
     43 import android.os.Message;
     44 import android.os.Parcel;
     45 import android.os.Parcelable;
     46 import android.os.RemoteException;
     47 import android.os.SystemClock;
     48 import android.os.SystemProperties;
     49 import android.util.AttributeSet;
     50 import android.util.Config;
     51 import android.util.EventLog;
     52 import android.util.Log;
     53 import android.util.Pool;
     54 import android.util.Poolable;
     55 import android.util.PoolableManager;
     56 import android.util.Pools;
     57 import android.util.SparseArray;
     58 import android.view.ContextMenu.ContextMenuInfo;
     59 import android.view.accessibility.AccessibilityEvent;
     60 import android.view.accessibility.AccessibilityEventSource;
     61 import android.view.accessibility.AccessibilityManager;
     62 import android.view.animation.Animation;
     63 import android.view.animation.AnimationUtils;
     64 import android.view.inputmethod.EditorInfo;
     65 import android.view.inputmethod.InputConnection;
     66 import android.view.inputmethod.InputMethodManager;
     67 import android.widget.ScrollBarDrawable;
     68 
     69 import java.lang.ref.SoftReference;
     70 import java.lang.reflect.InvocationTargetException;
     71 import java.lang.reflect.Method;
     72 import java.util.ArrayList;
     73 import java.util.Arrays;
     74 import java.util.WeakHashMap;
     75 
     76 /**
     77  * <p>
     78  * This class represents the basic building block for user interface components. A View
     79  * occupies a rectangular area on the screen and is responsible for drawing and
     80  * event handling. View is the base class for <em>widgets</em>, which are
     81  * used to create interactive UI components (buttons, text fields, etc.). The
     82  * {@link android.view.ViewGroup} subclass is the base class for <em>layouts</em>, which
     83  * are invisible containers that hold other Views (or other ViewGroups) and define
     84  * their layout properties.
     85  * </p>
     86  *
     87  * <div class="special">
     88  * <p>For an introduction to using this class to develop your
     89  * application's user interface, read the Developer Guide documentation on
     90  * <strong><a href="{@docRoot}guide/topics/ui/index.html">User Interface</a></strong>. Special topics
     91  * include:
     92  * <br/><a href="{@docRoot}guide/topics/ui/declaring-layout.html">Declaring Layout</a>
     93  * <br/><a href="{@docRoot}guide/topics/ui/menus.html">Creating Menus</a>
     94  * <br/><a href="{@docRoot}guide/topics/ui/layout-objects.html">Common Layout Objects</a>
     95  * <br/><a href="{@docRoot}guide/topics/ui/binding.html">Binding to Data with AdapterView</a>
     96  * <br/><a href="{@docRoot}guide/topics/ui/ui-events.html">Handling UI Events</a>
     97  * <br/><a href="{@docRoot}guide/topics/ui/themes.html">Applying Styles and Themes</a>
     98  * <br/><a href="{@docRoot}guide/topics/ui/custom-components.html">Building Custom Components</a>
     99  * <br/><a href="{@docRoot}guide/topics/ui/how-android-draws.html">How Android Draws Views</a>.
    100  * </p>
    101  * </div>
    102  *
    103  * <a name="Using"></a>
    104  * <h3>Using Views</h3>
    105  * <p>
    106  * All of the views in a window are arranged in a single tree. You can add views
    107  * either from code or by specifying a tree of views in one or more XML layout
    108  * files. There are many specialized subclasses of views that act as controls or
    109  * are capable of displaying text, images, or other content.
    110  * </p>
    111  * <p>
    112  * Once you have created a tree of views, there are typically a few types of
    113  * common operations you may wish to perform:
    114  * <ul>
    115  * <li><strong>Set properties:</strong> for example setting the text of a
    116  * {@link android.widget.TextView}. The available properties and the methods
    117  * that set them will vary among the different subclasses of views. Note that
    118  * properties that are known at build time can be set in the XML layout
    119  * files.</li>
    120  * <li><strong>Set focus:</strong> The framework will handled moving focus in
    121  * response to user input. To force focus to a specific view, call
    122  * {@link #requestFocus}.</li>
    123  * <li><strong>Set up listeners:</strong> Views allow clients to set listeners
    124  * that will be notified when something interesting happens to the view. For
    125  * example, all views will let you set a listener to be notified when the view
    126  * gains or loses focus. You can register such a listener using
    127  * {@link #setOnFocusChangeListener}. Other view subclasses offer more
    128  * specialized listeners. For example, a Button exposes a listener to notify
    129  * clients when the button is clicked.</li>
    130  * <li><strong>Set visibility:</strong> You can hide or show views using
    131  * {@link #setVisibility}.</li>
    132  * </ul>
    133  * </p>
    134  * <p><em>
    135  * Note: The Android framework is responsible for measuring, laying out and
    136  * drawing views. You should not call methods that perform these actions on
    137  * views yourself unless you are actually implementing a
    138  * {@link android.view.ViewGroup}.
    139  * </em></p>
    140  *
    141  * <a name="Lifecycle"></a>
    142  * <h3>Implementing a Custom View</h3>
    143  *
    144  * <p>
    145  * To implement a custom view, you will usually begin by providing overrides for
    146  * some of the standard methods that the framework calls on all views. You do
    147  * not need to override all of these methods. In fact, you can start by just
    148  * overriding {@link #onDraw(android.graphics.Canvas)}.
    149  * <table border="2" width="85%" align="center" cellpadding="5">
    150  *     <thead>
    151  *         <tr><th>Category</th> <th>Methods</th> <th>Description</th></tr>
    152  *     </thead>
    153  *
    154  *     <tbody>
    155  *     <tr>
    156  *         <td rowspan="2">Creation</td>
    157  *         <td>Constructors</td>
    158  *         <td>There is a form of the constructor that are called when the view
    159  *         is created from code and a form that is called when the view is
    160  *         inflated from a layout file. The second form should parse and apply
    161  *         any attributes defined in the layout file.
    162  *         </td>
    163  *     </tr>
    164  *     <tr>
    165  *         <td><code>{@link #onFinishInflate()}</code></td>
    166  *         <td>Called after a view and all of its children has been inflated
    167  *         from XML.</td>
    168  *     </tr>
    169  *
    170  *     <tr>
    171  *         <td rowspan="3">Layout</td>
    172  *         <td><code>{@link #onMeasure}</code></td>
    173  *         <td>Called to determine the size requirements for this view and all
    174  *         of its children.
    175  *         </td>
    176  *     </tr>
    177  *     <tr>
    178  *         <td><code>{@link #onLayout}</code></td>
    179  *         <td>Called when this view should assign a size and position to all
    180  *         of its children.
    181  *         </td>
    182  *     </tr>
    183  *     <tr>
    184  *         <td><code>{@link #onSizeChanged}</code></td>
    185  *         <td>Called when the size of this view has changed.
    186  *         </td>
    187  *     </tr>
    188  *
    189  *     <tr>
    190  *         <td>Drawing</td>
    191  *         <td><code>{@link #onDraw}</code></td>
    192  *         <td>Called when the view should render its content.
    193  *         </td>
    194  *     </tr>
    195  *
    196  *     <tr>
    197  *         <td rowspan="4">Event processing</td>
    198  *         <td><code>{@link #onKeyDown}</code></td>
    199  *         <td>Called when a new key event occurs.
    200  *         </td>
    201  *     </tr>
    202  *     <tr>
    203  *         <td><code>{@link #onKeyUp}</code></td>
    204  *         <td>Called when a key up event occurs.
    205  *         </td>
    206  *     </tr>
    207  *     <tr>
    208  *         <td><code>{@link #onTrackballEvent}</code></td>
    209  *         <td>Called when a trackball motion event occurs.
    210  *         </td>
    211  *     </tr>
    212  *     <tr>
    213  *         <td><code>{@link #onTouchEvent}</code></td>
    214  *         <td>Called when a touch screen motion event occurs.
    215  *         </td>
    216  *     </tr>
    217  *
    218  *     <tr>
    219  *         <td rowspan="2">Focus</td>
    220  *         <td><code>{@link #onFocusChanged}</code></td>
    221  *         <td>Called when the view gains or loses focus.
    222  *         </td>
    223  *     </tr>
    224  *
    225  *     <tr>
    226  *         <td><code>{@link #onWindowFocusChanged}</code></td>
    227  *         <td>Called when the window containing the view gains or loses focus.
    228  *         </td>
    229  *     </tr>
    230  *
    231  *     <tr>
    232  *         <td rowspan="3">Attaching</td>
    233  *         <td><code>{@link #onAttachedToWindow()}</code></td>
    234  *         <td>Called when the view is attached to a window.
    235  *         </td>
    236  *     </tr>
    237  *
    238  *     <tr>
    239  *         <td><code>{@link #onDetachedFromWindow}</code></td>
    240  *         <td>Called when the view is detached from its window.
    241  *         </td>
    242  *     </tr>
    243  *
    244  *     <tr>
    245  *         <td><code>{@link #onWindowVisibilityChanged}</code></td>
    246  *         <td>Called when the visibility of the window containing the view
    247  *         has changed.
    248  *         </td>
    249  *     </tr>
    250  *     </tbody>
    251  *
    252  * </table>
    253  * </p>
    254  *
    255  * <a name="IDs"></a>
    256  * <h3>IDs</h3>
    257  * Views may have an integer id associated with them. These ids are typically
    258  * assigned in the layout XML files, and are used to find specific views within
    259  * the view tree. A common pattern is to:
    260  * <ul>
    261  * <li>Define a Button in the layout file and assign it a unique ID.
    262  * <pre>
    263  * &lt;Button id="@+id/my_button"
    264  *     android:layout_width="wrap_content"
    265  *     android:layout_height="wrap_content"
    266  *     android:text="@string/my_button_text"/&gt;
    267  * </pre></li>
    268  * <li>From the onCreate method of an Activity, find the Button
    269  * <pre class="prettyprint">
    270  *      Button myButton = (Button) findViewById(R.id.my_button);
    271  * </pre></li>
    272  * </ul>
    273  * <p>
    274  * View IDs need not be unique throughout the tree, but it is good practice to
    275  * ensure that they are at least unique within the part of the tree you are
    276  * searching.
    277  * </p>
    278  *
    279  * <a name="Position"></a>
    280  * <h3>Position</h3>
    281  * <p>
    282  * The geometry of a view is that of a rectangle. A view has a location,
    283  * expressed as a pair of <em>left</em> and <em>top</em> coordinates, and
    284  * two dimensions, expressed as a width and a height. The unit for location
    285  * and dimensions is the pixel.
    286  * </p>
    287  *
    288  * <p>
    289  * It is possible to retrieve the location of a view by invoking the methods
    290  * {@link #getLeft()} and {@link #getTop()}. The former returns the left, or X,
    291  * coordinate of the rectangle representing the view. The latter returns the
    292  * top, or Y, coordinate of the rectangle representing the view. These methods
    293  * both return the location of the view relative to its parent. For instance,
    294  * when getLeft() returns 20, that means the view is located 20 pixels to the
    295  * right of the left edge of its direct parent.
    296  * </p>
    297  *
    298  * <p>
    299  * In addition, several convenience methods are offered to avoid unnecessary
    300  * computations, namely {@link #getRight()} and {@link #getBottom()}.
    301  * These methods return the coordinates of the right and bottom edges of the
    302  * rectangle representing the view. For instance, calling {@link #getRight()}
    303  * is similar to the following computation: <code>getLeft() + getWidth()</code>
    304  * (see <a href="#SizePaddingMargins">Size</a> for more information about the width.)
    305  * </p>
    306  *
    307  * <a name="SizePaddingMargins"></a>
    308  * <h3>Size, padding and margins</h3>
    309  * <p>
    310  * The size of a view is expressed with a width and a height. A view actually
    311  * possess two pairs of width and height values.
    312  * </p>
    313  *
    314  * <p>
    315  * The first pair is known as <em>measured width</em> and
    316  * <em>measured height</em>. These dimensions define how big a view wants to be
    317  * within its parent (see <a href="#Layout">Layout</a> for more details.) The
    318  * measured dimensions can be obtained by calling {@link #getMeasuredWidth()}
    319  * and {@link #getMeasuredHeight()}.
    320  * </p>
    321  *
    322  * <p>
    323  * The second pair is simply known as <em>width</em> and <em>height</em>, or
    324  * sometimes <em>drawing width</em> and <em>drawing height</em>. These
    325  * dimensions define the actual size of the view on screen, at drawing time and
    326  * after layout. These values may, but do not have to, be different from the
    327  * measured width and height. The width and height can be obtained by calling
    328  * {@link #getWidth()} and {@link #getHeight()}.
    329  * </p>
    330  *
    331  * <p>
    332  * To measure its dimensions, a view takes into account its padding. The padding
    333  * is expressed in pixels for the left, top, right and bottom parts of the view.
    334  * Padding can be used to offset the content of the view by a specific amount of
    335  * pixels. For instance, a left padding of 2 will push the view's content by
    336  * 2 pixels to the right of the left edge. Padding can be set using the
    337  * {@link #setPadding(int, int, int, int)} method and queried by calling
    338  * {@link #getPaddingLeft()}, {@link #getPaddingTop()},
    339  * {@link #getPaddingRight()} and {@link #getPaddingBottom()}.
    340  * </p>
    341  *
    342  * <p>
    343  * Even though a view can define a padding, it does not provide any support for
    344  * margins. However, view groups provide such a support. Refer to
    345  * {@link android.view.ViewGroup} and
    346  * {@link android.view.ViewGroup.MarginLayoutParams} for further information.
    347  * </p>
    348  *
    349  * <a name="Layout"></a>
    350  * <h3>Layout</h3>
    351  * <p>
    352  * Layout is a two pass process: a measure pass and a layout pass. The measuring
    353  * pass is implemented in {@link #measure(int, int)} and is a top-down traversal
    354  * of the view tree. Each view pushes dimension specifications down the tree
    355  * during the recursion. At the end of the measure pass, every view has stored
    356  * its measurements. The second pass happens in
    357  * {@link #layout(int,int,int,int)} and is also top-down. During
    358  * this pass each parent is responsible for positioning all of its children
    359  * using the sizes computed in the measure pass.
    360  * </p>
    361  *
    362  * <p>
    363  * When a view's measure() method returns, its {@link #getMeasuredWidth()} and
    364  * {@link #getMeasuredHeight()} values must be set, along with those for all of
    365  * that view's descendants. A view's measured width and measured height values
    366  * must respect the constraints imposed by the view's parents. This guarantees
    367  * that at the end of the measure pass, all parents accept all of their
    368  * children's measurements. A parent view may call measure() more than once on
    369  * its children. For example, the parent may measure each child once with
    370  * unspecified dimensions to find out how big they want to be, then call
    371  * measure() on them again with actual numbers if the sum of all the children's
    372  * unconstrained sizes is too big or too small.
    373  * </p>
    374  *
    375  * <p>
    376  * The measure pass uses two classes to communicate dimensions. The
    377  * {@link MeasureSpec} class is used by views to tell their parents how they
    378  * want to be measured and positioned. The base LayoutParams class just
    379  * describes how big the view wants to be for both width and height. For each
    380  * dimension, it can specify one of:
    381  * <ul>
    382  * <li> an exact number
    383  * <li>MATCH_PARENT, which means the view wants to be as big as its parent
    384  * (minus padding)
    385  * <li> WRAP_CONTENT, which means that the view wants to be just big enough to
    386  * enclose its content (plus padding).
    387  * </ul>
    388  * There are subclasses of LayoutParams for different subclasses of ViewGroup.
    389  * For example, AbsoluteLayout has its own subclass of LayoutParams which adds
    390  * an X and Y value.
    391  * </p>
    392  *
    393  * <p>
    394  * MeasureSpecs are used to push requirements down the tree from parent to
    395  * child. A MeasureSpec can be in one of three modes:
    396  * <ul>
    397  * <li>UNSPECIFIED: This is used by a parent to determine the desired dimension
    398  * of a child view. For example, a LinearLayout may call measure() on its child
    399  * with the height set to UNSPECIFIED and a width of EXACTLY 240 to find out how
    400  * tall the child view wants to be given a width of 240 pixels.
    401  * <li>EXACTLY: This is used by the parent to impose an exact size on the
    402  * child. The child must use this size, and guarantee that all of its
    403  * descendants will fit within this size.
    404  * <li>AT_MOST: This is used by the parent to impose a maximum size on the
    405  * child. The child must gurantee that it and all of its descendants will fit
    406  * within this size.
    407  * </ul>
    408  * </p>
    409  *
    410  * <p>
    411  * To intiate a layout, call {@link #requestLayout}. This method is typically
    412  * called by a view on itself when it believes that is can no longer fit within
    413  * its current bounds.
    414  * </p>
    415  *
    416  * <a name="Drawing"></a>
    417  * <h3>Drawing</h3>
    418  * <p>
    419  * Drawing is handled by walking the tree and rendering each view that
    420  * intersects the the invalid region. Because the tree is traversed in-order,
    421  * this means that parents will draw before (i.e., behind) their children, with
    422  * siblings drawn in the order they appear in the tree.
    423  * If you set a background drawable for a View, then the View will draw it for you
    424  * before calling back to its <code>onDraw()</code> method.
    425  * </p>
    426  *
    427  * <p>
    428  * Note that the framework will not draw views that are not in the invalid region.
    429  * </p>
    430  *
    431  * <p>
    432  * To force a view to draw, call {@link #invalidate()}.
    433  * </p>
    434  *
    435  * <a name="EventHandlingThreading"></a>
    436  * <h3>Event Handling and Threading</h3>
    437  * <p>
    438  * The basic cycle of a view is as follows:
    439  * <ol>
    440  * <li>An event comes in and is dispatched to the appropriate view. The view
    441  * handles the event and notifies any listeners.</li>
    442  * <li>If in the course of processing the event, the view's bounds may need
    443  * to be changed, the view will call {@link #requestLayout()}.</li>
    444  * <li>Similarly, if in the course of processing the event the view's appearance
    445  * may need to be changed, the view will call {@link #invalidate()}.</li>
    446  * <li>If either {@link #requestLayout()} or {@link #invalidate()} were called,
    447  * the framework will take care of measuring, laying out, and drawing the tree
    448  * as appropriate.</li>
    449  * </ol>
    450  * </p>
    451  *
    452  * <p><em>Note: The entire view tree is single threaded. You must always be on
    453  * the UI thread when calling any method on any view.</em>
    454  * If you are doing work on other threads and want to update the state of a view
    455  * from that thread, you should use a {@link Handler}.
    456  * </p>
    457  *
    458  * <a name="FocusHandling"></a>
    459  * <h3>Focus Handling</h3>
    460  * <p>
    461  * The framework will handle routine focus movement in response to user input.
    462  * This includes changing the focus as views are removed or hidden, or as new
    463  * views become available. Views indicate their willingness to take focus
    464  * through the {@link #isFocusable} method. To change whether a view can take
    465  * focus, call {@link #setFocusable(boolean)}.  When in touch mode (see notes below)
    466  * views indicate whether they still would like focus via {@link #isFocusableInTouchMode}
    467  * and can change this via {@link #setFocusableInTouchMode(boolean)}.
    468  * </p>
    469  * <p>
    470  * Focus movement is based on an algorithm which finds the nearest neighbor in a
    471  * given direction. In rare cases, the default algorithm may not match the
    472  * intended behavior of the developer. In these situations, you can provide
    473  * explicit overrides by using these XML attributes in the layout file:
    474  * <pre>
    475  * nextFocusDown
    476  * nextFocusLeft
    477  * nextFocusRight
    478  * nextFocusUp
    479  * </pre>
    480  * </p>
    481  *
    482  *
    483  * <p>
    484  * To get a particular view to take focus, call {@link #requestFocus()}.
    485  * </p>
    486  *
    487  * <a name="TouchMode"></a>
    488  * <h3>Touch Mode</h3>
    489  * <p>
    490  * When a user is navigating a user interface via directional keys such as a D-pad, it is
    491  * necessary to give focus to actionable items such as buttons so the user can see
    492  * what will take input.  If the device has touch capabilities, however, and the user
    493  * begins interacting with the interface by touching it, it is no longer necessary to
    494  * always highlight, or give focus to, a particular view.  This motivates a mode
    495  * for interaction named 'touch mode'.
    496  * </p>
    497  * <p>
    498  * For a touch capable device, once the user touches the screen, the device
    499  * will enter touch mode.  From this point onward, only views for which
    500  * {@link #isFocusableInTouchMode} is true will be focusable, such as text editing widgets.
    501  * Other views that are touchable, like buttons, will not take focus when touched; they will
    502  * only fire the on click listeners.
    503  * </p>
    504  * <p>
    505  * Any time a user hits a directional key, such as a D-pad direction, the view device will
    506  * exit touch mode, and find a view to take focus, so that the user may resume interacting
    507  * with the user interface without touching the screen again.
    508  * </p>
    509  * <p>
    510  * The touch mode state is maintained across {@link android.app.Activity}s.  Call
    511  * {@link #isInTouchMode} to see whether the device is currently in touch mode.
    512  * </p>
    513  *
    514  * <a name="Scrolling"></a>
    515  * <h3>Scrolling</h3>
    516  * <p>
    517  * The framework provides basic support for views that wish to internally
    518  * scroll their content. This includes keeping track of the X and Y scroll
    519  * offset as well as mechanisms for drawing scrollbars. See
    520  * {@link #scrollBy(int, int)}, {@link #scrollTo(int, int)}, and
    521  * {@link #awakenScrollBars()} for more details.
    522  * </p>
    523  *
    524  * <a name="Tags"></a>
    525  * <h3>Tags</h3>
    526  * <p>
    527  * Unlike IDs, tags are not used to identify views. Tags are essentially an
    528  * extra piece of information that can be associated with a view. They are most
    529  * often used as a convenience to store data related to views in the views
    530  * themselves rather than by putting them in a separate structure.
    531  * </p>
    532  *
    533  * <a name="Animation"></a>
    534  * <h3>Animation</h3>
    535  * <p>
    536  * You can attach an {@link Animation} object to a view using
    537  * {@link #setAnimation(Animation)} or
    538  * {@link #startAnimation(Animation)}. The animation can alter the scale,
    539  * rotation, translation and alpha of a view over time. If the animation is
    540  * attached to a view that has children, the animation will affect the entire
    541  * subtree rooted by that node. When an animation is started, the framework will
    542  * take care of redrawing the appropriate views until the animation completes.
    543  * </p>
    544  *
    545  * @attr ref android.R.styleable#View_background
    546  * @attr ref android.R.styleable#View_clickable
    547  * @attr ref android.R.styleable#View_contentDescription
    548  * @attr ref android.R.styleable#View_drawingCacheQuality
    549  * @attr ref android.R.styleable#View_duplicateParentState
    550  * @attr ref android.R.styleable#View_id
    551  * @attr ref android.R.styleable#View_fadingEdge
    552  * @attr ref android.R.styleable#View_fadingEdgeLength
    553  * @attr ref android.R.styleable#View_fitsSystemWindows
    554  * @attr ref android.R.styleable#View_isScrollContainer
    555  * @attr ref android.R.styleable#View_focusable
    556  * @attr ref android.R.styleable#View_focusableInTouchMode
    557  * @attr ref android.R.styleable#View_hapticFeedbackEnabled
    558  * @attr ref android.R.styleable#View_keepScreenOn
    559  * @attr ref android.R.styleable#View_longClickable
    560  * @attr ref android.R.styleable#View_minHeight
    561  * @attr ref android.R.styleable#View_minWidth
    562  * @attr ref android.R.styleable#View_nextFocusDown
    563  * @attr ref android.R.styleable#View_nextFocusLeft
    564  * @attr ref android.R.styleable#View_nextFocusRight
    565  * @attr ref android.R.styleable#View_nextFocusUp
    566  * @attr ref android.R.styleable#View_onClick
    567  * @attr ref android.R.styleable#View_padding
    568  * @attr ref android.R.styleable#View_paddingBottom
    569  * @attr ref android.R.styleable#View_paddingLeft
    570  * @attr ref android.R.styleable#View_paddingRight
    571  * @attr ref android.R.styleable#View_paddingTop
    572  * @attr ref android.R.styleable#View_saveEnabled
    573  * @attr ref android.R.styleable#View_scrollX
    574  * @attr ref android.R.styleable#View_scrollY
    575  * @attr ref android.R.styleable#View_scrollbarSize
    576  * @attr ref android.R.styleable#View_scrollbarStyle
    577  * @attr ref android.R.styleable#View_scrollbars
    578  * @attr ref android.R.styleable#View_scrollbarDefaultDelayBeforeFade
    579  * @attr ref android.R.styleable#View_scrollbarFadeDuration
    580  * @attr ref android.R.styleable#View_scrollbarTrackHorizontal
    581  * @attr ref android.R.styleable#View_scrollbarThumbHorizontal
    582  * @attr ref android.R.styleable#View_scrollbarThumbVertical
    583  * @attr ref android.R.styleable#View_scrollbarTrackVertical
    584  * @attr ref android.R.styleable#View_scrollbarAlwaysDrawHorizontalTrack
    585  * @attr ref android.R.styleable#View_scrollbarAlwaysDrawVerticalTrack
    586  * @attr ref android.R.styleable#View_soundEffectsEnabled
    587  * @attr ref android.R.styleable#View_tag
    588  * @attr ref android.R.styleable#View_visibility
    589  *
    590  * @see android.view.ViewGroup
    591  */
    592 public class View implements Drawable.Callback, KeyEvent.Callback, AccessibilityEventSource {
    593     private static final boolean DBG = false;
    594 
    595     /**
    596      * The logging tag used by this class with android.util.Log.
    597      */
    598     protected static final String VIEW_LOG_TAG = "View";
    599 
    600     /**
    601      * Used to mark a View that has no ID.
    602      */
    603     public static final int NO_ID = -1;
    604 
    605     /**
    606      * This view does not want keystrokes. Use with TAKES_FOCUS_MASK when
    607      * calling setFlags.
    608      */
    609     private static final int NOT_FOCUSABLE = 0x00000000;
    610 
    611     /**
    612      * This view wants keystrokes. Use with TAKES_FOCUS_MASK when calling
    613      * setFlags.
    614      */
    615     private static final int FOCUSABLE = 0x00000001;
    616 
    617     /**
    618      * Mask for use with setFlags indicating bits used for focus.
    619      */
    620     private static final int FOCUSABLE_MASK = 0x00000001;
    621 
    622     /**
    623      * This view will adjust its padding to fit sytem windows (e.g. status bar)
    624      */
    625     private static final int FITS_SYSTEM_WINDOWS = 0x00000002;
    626 
    627     /**
    628      * This view is visible.  Use with {@link #setVisibility}.
    629      */
    630     public static final int VISIBLE = 0x00000000;
    631 
    632     /**
    633      * This view is invisible, but it still takes up space for layout purposes.
    634      * Use with {@link #setVisibility}.
    635      */
    636     public static final int INVISIBLE = 0x00000004;
    637 
    638     /**
    639      * This view is invisible, and it doesn't take any space for layout
    640      * purposes. Use with {@link #setVisibility}.
    641      */
    642     public static final int GONE = 0x00000008;
    643 
    644     /**
    645      * Mask for use with setFlags indicating bits used for visibility.
    646      * {@hide}
    647      */
    648     static final int VISIBILITY_MASK = 0x0000000C;
    649 
    650     private static final int[] VISIBILITY_FLAGS = {VISIBLE, INVISIBLE, GONE};
    651 
    652     /**
    653      * This view is enabled. Intrepretation varies by subclass.
    654      * Use with ENABLED_MASK when calling setFlags.
    655      * {@hide}
    656      */
    657     static final int ENABLED = 0x00000000;
    658 
    659     /**
    660      * This view is disabled. Intrepretation varies by subclass.
    661      * Use with ENABLED_MASK when calling setFlags.
    662      * {@hide}
    663      */
    664     static final int DISABLED = 0x00000020;
    665 
    666    /**
    667     * Mask for use with setFlags indicating bits used for indicating whether
    668     * this view is enabled
    669     * {@hide}
    670     */
    671     static final int ENABLED_MASK = 0x00000020;
    672 
    673     /**
    674      * This view won't draw. {@link #onDraw} won't be called and further
    675      * optimizations
    676      * will be performed. It is okay to have this flag set and a background.
    677      * Use with DRAW_MASK when calling setFlags.
    678      * {@hide}
    679      */
    680     static final int WILL_NOT_DRAW = 0x00000080;
    681 
    682     /**
    683      * Mask for use with setFlags indicating bits used for indicating whether
    684      * this view is will draw
    685      * {@hide}
    686      */
    687     static final int DRAW_MASK = 0x00000080;
    688 
    689     /**
    690      * <p>This view doesn't show scrollbars.</p>
    691      * {@hide}
    692      */
    693     static final int SCROLLBARS_NONE = 0x00000000;
    694 
    695     /**
    696      * <p>This view shows horizontal scrollbars.</p>
    697      * {@hide}
    698      */
    699     static final int SCROLLBARS_HORIZONTAL = 0x00000100;
    700 
    701     /**
    702      * <p>This view shows vertical scrollbars.</p>
    703      * {@hide}
    704      */
    705     static final int SCROLLBARS_VERTICAL = 0x00000200;
    706 
    707     /**
    708      * <p>Mask for use with setFlags indicating bits used for indicating which
    709      * scrollbars are enabled.</p>
    710      * {@hide}
    711      */
    712     static final int SCROLLBARS_MASK = 0x00000300;
    713 
    714     // note 0x00000400 and 0x00000800 are now available for next flags...
    715 
    716     /**
    717      * <p>This view doesn't show fading edges.</p>
    718      * {@hide}
    719      */
    720     static final int FADING_EDGE_NONE = 0x00000000;
    721 
    722     /**
    723      * <p>This view shows horizontal fading edges.</p>
    724      * {@hide}
    725      */
    726     static final int FADING_EDGE_HORIZONTAL = 0x00001000;
    727 
    728     /**
    729      * <p>This view shows vertical fading edges.</p>
    730      * {@hide}
    731      */
    732     static final int FADING_EDGE_VERTICAL = 0x00002000;
    733 
    734     /**
    735      * <p>Mask for use with setFlags indicating bits used for indicating which
    736      * fading edges are enabled.</p>
    737      * {@hide}
    738      */
    739     static final int FADING_EDGE_MASK = 0x00003000;
    740 
    741     /**
    742      * <p>Indicates this view can be clicked. When clickable, a View reacts
    743      * to clicks by notifying the OnClickListener.<p>
    744      * {@hide}
    745      */
    746     static final int CLICKABLE = 0x00004000;
    747 
    748     /**
    749      * <p>Indicates this view is caching its drawing into a bitmap.</p>
    750      * {@hide}
    751      */
    752     static final int DRAWING_CACHE_ENABLED = 0x00008000;
    753 
    754     /**
    755      * <p>Indicates that no icicle should be saved for this view.<p>
    756      * {@hide}
    757      */
    758     static final int SAVE_DISABLED = 0x000010000;
    759 
    760     /**
    761      * <p>Mask for use with setFlags indicating bits used for the saveEnabled
    762      * property.</p>
    763      * {@hide}
    764      */
    765     static final int SAVE_DISABLED_MASK = 0x000010000;
    766 
    767     /**
    768      * <p>Indicates that no drawing cache should ever be created for this view.<p>
    769      * {@hide}
    770      */
    771     static final int WILL_NOT_CACHE_DRAWING = 0x000020000;
    772 
    773     /**
    774      * <p>Indicates this view can take / keep focus when int touch mode.</p>
    775      * {@hide}
    776      */
    777     static final int FOCUSABLE_IN_TOUCH_MODE = 0x00040000;
    778 
    779     /**
    780      * <p>Enables low quality mode for the drawing cache.</p>
    781      */
    782     public static final int DRAWING_CACHE_QUALITY_LOW = 0x00080000;
    783 
    784     /**
    785      * <p>Enables high quality mode for the drawing cache.</p>
    786      */
    787     public static final int DRAWING_CACHE_QUALITY_HIGH = 0x00100000;
    788 
    789     /**
    790      * <p>Enables automatic quality mode for the drawing cache.</p>
    791      */
    792     public static final int DRAWING_CACHE_QUALITY_AUTO = 0x00000000;
    793 
    794     private static final int[] DRAWING_CACHE_QUALITY_FLAGS = {
    795             DRAWING_CACHE_QUALITY_AUTO, DRAWING_CACHE_QUALITY_LOW, DRAWING_CACHE_QUALITY_HIGH
    796     };
    797 
    798     /**
    799      * <p>Mask for use with setFlags indicating bits used for the cache
    800      * quality property.</p>
    801      * {@hide}
    802      */
    803     static final int DRAWING_CACHE_QUALITY_MASK = 0x00180000;
    804 
    805     /**
    806      * <p>
    807      * Indicates this view can be long clicked. When long clickable, a View
    808      * reacts to long clicks by notifying the OnLongClickListener or showing a
    809      * context menu.
    810      * </p>
    811      * {@hide}
    812      */
    813     static final int LONG_CLICKABLE = 0x00200000;
    814 
    815     /**
    816      * <p>Indicates that this view gets its drawable states from its direct parent
    817      * and ignores its original internal states.</p>
    818      *
    819      * @hide
    820      */
    821     static final int DUPLICATE_PARENT_STATE = 0x00400000;
    822 
    823     /**
    824      * The scrollbar style to display the scrollbars inside the content area,
    825      * without increasing the padding. The scrollbars will be overlaid with
    826      * translucency on the view's content.
    827      */
    828     public static final int SCROLLBARS_INSIDE_OVERLAY = 0;
    829 
    830     /**
    831      * The scrollbar style to display the scrollbars inside the padded area,
    832      * increasing the padding of the view. The scrollbars will not overlap the
    833      * content area of the view.
    834      */
    835     public static final int SCROLLBARS_INSIDE_INSET = 0x01000000;
    836 
    837     /**
    838      * The scrollbar style to display the scrollbars at the edge of the view,
    839      * without increasing the padding. The scrollbars will be overlaid with
    840      * translucency.
    841      */
    842     public static final int SCROLLBARS_OUTSIDE_OVERLAY = 0x02000000;
    843 
    844     /**
    845      * The scrollbar style to display the scrollbars at the edge of the view,
    846      * increasing the padding of the view. The scrollbars will only overlap the
    847      * background, if any.
    848      */
    849     public static final int SCROLLBARS_OUTSIDE_INSET = 0x03000000;
    850 
    851     /**
    852      * Mask to check if the scrollbar style is overlay or inset.
    853      * {@hide}
    854      */
    855     static final int SCROLLBARS_INSET_MASK = 0x01000000;
    856 
    857     /**
    858      * Mask to check if the scrollbar style is inside or outside.
    859      * {@hide}
    860      */
    861     static final int SCROLLBARS_OUTSIDE_MASK = 0x02000000;
    862 
    863     /**
    864      * Mask for scrollbar style.
    865      * {@hide}
    866      */
    867     static final int SCROLLBARS_STYLE_MASK = 0x03000000;
    868 
    869     /**
    870      * View flag indicating that the screen should remain on while the
    871      * window containing this view is visible to the user.  This effectively
    872      * takes care of automatically setting the WindowManager's
    873      * {@link WindowManager.LayoutParams#FLAG_KEEP_SCREEN_ON}.
    874      */
    875     public static final int KEEP_SCREEN_ON = 0x04000000;
    876 
    877     /**
    878      * View flag indicating whether this view should have sound effects enabled
    879      * for events such as clicking and touching.
    880      */
    881     public static final int SOUND_EFFECTS_ENABLED = 0x08000000;
    882 
    883     /**
    884      * View flag indicating whether this view should have haptic feedback
    885      * enabled for events such as long presses.
    886      */
    887     public static final int HAPTIC_FEEDBACK_ENABLED = 0x10000000;
    888 
    889     /**
    890      * View flag indicating whether {@link #addFocusables(ArrayList, int, int)}
    891      * should add all focusable Views regardless if they are focusable in touch mode.
    892      */
    893     public static final int FOCUSABLES_ALL = 0x00000000;
    894 
    895     /**
    896      * View flag indicating whether {@link #addFocusables(ArrayList, int, int)}
    897      * should add only Views focusable in touch mode.
    898      */
    899     public static final int FOCUSABLES_TOUCH_MODE = 0x00000001;
    900 
    901     /**
    902      * Use with {@link #focusSearch}. Move focus to the previous selectable
    903      * item.
    904      */
    905     public static final int FOCUS_BACKWARD = 0x00000001;
    906 
    907     /**
    908      * Use with {@link #focusSearch}. Move focus to the next selectable
    909      * item.
    910      */
    911     public static final int FOCUS_FORWARD = 0x00000002;
    912 
    913     /**
    914      * Use with {@link #focusSearch}. Move focus to the left.
    915      */
    916     public static final int FOCUS_LEFT = 0x00000011;
    917 
    918     /**
    919      * Use with {@link #focusSearch}. Move focus up.
    920      */
    921     public static final int FOCUS_UP = 0x00000021;
    922 
    923     /**
    924      * Use with {@link #focusSearch}. Move focus to the right.
    925      */
    926     public static final int FOCUS_RIGHT = 0x00000042;
    927 
    928     /**
    929      * Use with {@link #focusSearch}. Move focus down.
    930      */
    931     public static final int FOCUS_DOWN = 0x00000082;
    932 
    933     /**
    934      * Base View state sets
    935      */
    936     // Singles
    937     /**
    938      * Indicates the view has no states set. States are used with
    939      * {@link android.graphics.drawable.Drawable} to change the drawing of the
    940      * view depending on its state.
    941      *
    942      * @see android.graphics.drawable.Drawable
    943      * @see #getDrawableState()
    944      */
    945     protected static final int[] EMPTY_STATE_SET = {};
    946     /**
    947      * Indicates the view is enabled. States are used with
    948      * {@link android.graphics.drawable.Drawable} to change the drawing of the
    949      * view depending on its state.
    950      *
    951      * @see android.graphics.drawable.Drawable
    952      * @see #getDrawableState()
    953      */
    954     protected static final int[] ENABLED_STATE_SET = {R.attr.state_enabled};
    955     /**
    956      * Indicates the view is focused. States are used with
    957      * {@link android.graphics.drawable.Drawable} to change the drawing of the
    958      * view depending on its state.
    959      *
    960      * @see android.graphics.drawable.Drawable
    961      * @see #getDrawableState()
    962      */
    963     protected static final int[] FOCUSED_STATE_SET = {R.attr.state_focused};
    964     /**
    965      * Indicates the view is selected. States are used with
    966      * {@link android.graphics.drawable.Drawable} to change the drawing of the
    967      * view depending on its state.
    968      *
    969      * @see android.graphics.drawable.Drawable
    970      * @see #getDrawableState()
    971      */
    972     protected static final int[] SELECTED_STATE_SET = {R.attr.state_selected};
    973     /**
    974      * Indicates the view is pressed. States are used with
    975      * {@link android.graphics.drawable.Drawable} to change the drawing of the
    976      * view depending on its state.
    977      *
    978      * @see android.graphics.drawable.Drawable
    979      * @see #getDrawableState()
    980      * @hide
    981      */
    982     protected static final int[] PRESSED_STATE_SET = {R.attr.state_pressed};
    983     /**
    984      * Indicates the view's window has focus. States are used with
    985      * {@link android.graphics.drawable.Drawable} to change the drawing of the
    986      * view depending on its state.
    987      *
    988      * @see android.graphics.drawable.Drawable
    989      * @see #getDrawableState()
    990      */
    991     protected static final int[] WINDOW_FOCUSED_STATE_SET =
    992             {R.attr.state_window_focused};
    993     // Doubles
    994     /**
    995      * Indicates the view is enabled and has the focus.
    996      *
    997      * @see #ENABLED_STATE_SET
    998      * @see #FOCUSED_STATE_SET
    999      */
   1000     protected static final int[] ENABLED_FOCUSED_STATE_SET =
   1001             stateSetUnion(ENABLED_STATE_SET, FOCUSED_STATE_SET);
   1002     /**
   1003      * Indicates the view is enabled and selected.
   1004      *
   1005      * @see #ENABLED_STATE_SET
   1006      * @see #SELECTED_STATE_SET
   1007      */
   1008     protected static final int[] ENABLED_SELECTED_STATE_SET =
   1009             stateSetUnion(ENABLED_STATE_SET, SELECTED_STATE_SET);
   1010     /**
   1011      * Indicates the view is enabled and that its window has focus.
   1012      *
   1013      * @see #ENABLED_STATE_SET
   1014      * @see #WINDOW_FOCUSED_STATE_SET
   1015      */
   1016     protected static final int[] ENABLED_WINDOW_FOCUSED_STATE_SET =
   1017             stateSetUnion(ENABLED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1018     /**
   1019      * Indicates the view is focused and selected.
   1020      *
   1021      * @see #FOCUSED_STATE_SET
   1022      * @see #SELECTED_STATE_SET
   1023      */
   1024     protected static final int[] FOCUSED_SELECTED_STATE_SET =
   1025             stateSetUnion(FOCUSED_STATE_SET, SELECTED_STATE_SET);
   1026     /**
   1027      * Indicates the view has the focus and that its window has the focus.
   1028      *
   1029      * @see #FOCUSED_STATE_SET
   1030      * @see #WINDOW_FOCUSED_STATE_SET
   1031      */
   1032     protected static final int[] FOCUSED_WINDOW_FOCUSED_STATE_SET =
   1033             stateSetUnion(FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1034     /**
   1035      * Indicates the view is selected and that its window has the focus.
   1036      *
   1037      * @see #SELECTED_STATE_SET
   1038      * @see #WINDOW_FOCUSED_STATE_SET
   1039      */
   1040     protected static final int[] SELECTED_WINDOW_FOCUSED_STATE_SET =
   1041             stateSetUnion(SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1042     // Triples
   1043     /**
   1044      * Indicates the view is enabled, focused and selected.
   1045      *
   1046      * @see #ENABLED_STATE_SET
   1047      * @see #FOCUSED_STATE_SET
   1048      * @see #SELECTED_STATE_SET
   1049      */
   1050     protected static final int[] ENABLED_FOCUSED_SELECTED_STATE_SET =
   1051             stateSetUnion(ENABLED_FOCUSED_STATE_SET, SELECTED_STATE_SET);
   1052     /**
   1053      * Indicates the view is enabled, focused and its window has the focus.
   1054      *
   1055      * @see #ENABLED_STATE_SET
   1056      * @see #FOCUSED_STATE_SET
   1057      * @see #WINDOW_FOCUSED_STATE_SET
   1058      */
   1059     protected static final int[] ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET =
   1060             stateSetUnion(ENABLED_FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1061     /**
   1062      * Indicates the view is enabled, selected and its window has the focus.
   1063      *
   1064      * @see #ENABLED_STATE_SET
   1065      * @see #SELECTED_STATE_SET
   1066      * @see #WINDOW_FOCUSED_STATE_SET
   1067      */
   1068     protected static final int[] ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1069             stateSetUnion(ENABLED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1070     /**
   1071      * Indicates the view is focused, selected and its window has the focus.
   1072      *
   1073      * @see #FOCUSED_STATE_SET
   1074      * @see #SELECTED_STATE_SET
   1075      * @see #WINDOW_FOCUSED_STATE_SET
   1076      */
   1077     protected static final int[] FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1078             stateSetUnion(FOCUSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1079     /**
   1080      * Indicates the view is enabled, focused, selected and its window
   1081      * has the focus.
   1082      *
   1083      * @see #ENABLED_STATE_SET
   1084      * @see #FOCUSED_STATE_SET
   1085      * @see #SELECTED_STATE_SET
   1086      * @see #WINDOW_FOCUSED_STATE_SET
   1087      */
   1088     protected static final int[] ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1089             stateSetUnion(ENABLED_FOCUSED_SELECTED_STATE_SET,
   1090                           WINDOW_FOCUSED_STATE_SET);
   1091 
   1092     /**
   1093      * Indicates the view is pressed and its window has the focus.
   1094      *
   1095      * @see #PRESSED_STATE_SET
   1096      * @see #WINDOW_FOCUSED_STATE_SET
   1097      */
   1098     protected static final int[] PRESSED_WINDOW_FOCUSED_STATE_SET =
   1099             stateSetUnion(PRESSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1100 
   1101     /**
   1102      * Indicates the view is pressed and selected.
   1103      *
   1104      * @see #PRESSED_STATE_SET
   1105      * @see #SELECTED_STATE_SET
   1106      */
   1107     protected static final int[] PRESSED_SELECTED_STATE_SET =
   1108             stateSetUnion(PRESSED_STATE_SET, SELECTED_STATE_SET);
   1109 
   1110     /**
   1111      * Indicates the view is pressed, selected and its window has the focus.
   1112      *
   1113      * @see #PRESSED_STATE_SET
   1114      * @see #SELECTED_STATE_SET
   1115      * @see #WINDOW_FOCUSED_STATE_SET
   1116      */
   1117     protected static final int[] PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1118             stateSetUnion(PRESSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1119 
   1120     /**
   1121      * Indicates the view is pressed and focused.
   1122      *
   1123      * @see #PRESSED_STATE_SET
   1124      * @see #FOCUSED_STATE_SET
   1125      */
   1126     protected static final int[] PRESSED_FOCUSED_STATE_SET =
   1127             stateSetUnion(PRESSED_STATE_SET, FOCUSED_STATE_SET);
   1128 
   1129     /**
   1130      * Indicates the view is pressed, focused and its window has the focus.
   1131      *
   1132      * @see #PRESSED_STATE_SET
   1133      * @see #FOCUSED_STATE_SET
   1134      * @see #WINDOW_FOCUSED_STATE_SET
   1135      */
   1136     protected static final int[] PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET =
   1137             stateSetUnion(PRESSED_FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1138 
   1139     /**
   1140      * Indicates the view is pressed, focused and selected.
   1141      *
   1142      * @see #PRESSED_STATE_SET
   1143      * @see #SELECTED_STATE_SET
   1144      * @see #FOCUSED_STATE_SET
   1145      */
   1146     protected static final int[] PRESSED_FOCUSED_SELECTED_STATE_SET =
   1147             stateSetUnion(PRESSED_FOCUSED_STATE_SET, SELECTED_STATE_SET);
   1148 
   1149     /**
   1150      * Indicates the view is pressed, focused, selected and its window has the focus.
   1151      *
   1152      * @see #PRESSED_STATE_SET
   1153      * @see #FOCUSED_STATE_SET
   1154      * @see #SELECTED_STATE_SET
   1155      * @see #WINDOW_FOCUSED_STATE_SET
   1156      */
   1157     protected static final int[] PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1158             stateSetUnion(PRESSED_FOCUSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1159 
   1160     /**
   1161      * Indicates the view is pressed and enabled.
   1162      *
   1163      * @see #PRESSED_STATE_SET
   1164      * @see #ENABLED_STATE_SET
   1165      */
   1166     protected static final int[] PRESSED_ENABLED_STATE_SET =
   1167             stateSetUnion(PRESSED_STATE_SET, ENABLED_STATE_SET);
   1168 
   1169     /**
   1170      * Indicates the view is pressed, enabled and its window has the focus.
   1171      *
   1172      * @see #PRESSED_STATE_SET
   1173      * @see #ENABLED_STATE_SET
   1174      * @see #WINDOW_FOCUSED_STATE_SET
   1175      */
   1176     protected static final int[] PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET =
   1177             stateSetUnion(PRESSED_ENABLED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1178 
   1179     /**
   1180      * Indicates the view is pressed, enabled and selected.
   1181      *
   1182      * @see #PRESSED_STATE_SET
   1183      * @see #ENABLED_STATE_SET
   1184      * @see #SELECTED_STATE_SET
   1185      */
   1186     protected static final int[] PRESSED_ENABLED_SELECTED_STATE_SET =
   1187             stateSetUnion(PRESSED_ENABLED_STATE_SET, SELECTED_STATE_SET);
   1188 
   1189     /**
   1190      * Indicates the view is pressed, enabled, selected and its window has the
   1191      * focus.
   1192      *
   1193      * @see #PRESSED_STATE_SET
   1194      * @see #ENABLED_STATE_SET
   1195      * @see #SELECTED_STATE_SET
   1196      * @see #WINDOW_FOCUSED_STATE_SET
   1197      */
   1198     protected static final int[] PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1199             stateSetUnion(PRESSED_ENABLED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1200 
   1201     /**
   1202      * Indicates the view is pressed, enabled and focused.
   1203      *
   1204      * @see #PRESSED_STATE_SET
   1205      * @see #ENABLED_STATE_SET
   1206      * @see #FOCUSED_STATE_SET
   1207      */
   1208     protected static final int[] PRESSED_ENABLED_FOCUSED_STATE_SET =
   1209             stateSetUnion(PRESSED_ENABLED_STATE_SET, FOCUSED_STATE_SET);
   1210 
   1211     /**
   1212      * Indicates the view is pressed, enabled, focused and its window has the
   1213      * focus.
   1214      *
   1215      * @see #PRESSED_STATE_SET
   1216      * @see #ENABLED_STATE_SET
   1217      * @see #FOCUSED_STATE_SET
   1218      * @see #WINDOW_FOCUSED_STATE_SET
   1219      */
   1220     protected static final int[] PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET =
   1221             stateSetUnion(PRESSED_ENABLED_FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1222 
   1223     /**
   1224      * Indicates the view is pressed, enabled, focused and selected.
   1225      *
   1226      * @see #PRESSED_STATE_SET
   1227      * @see #ENABLED_STATE_SET
   1228      * @see #SELECTED_STATE_SET
   1229      * @see #FOCUSED_STATE_SET
   1230      */
   1231     protected static final int[] PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET =
   1232             stateSetUnion(PRESSED_ENABLED_FOCUSED_STATE_SET, SELECTED_STATE_SET);
   1233 
   1234     /**
   1235      * Indicates the view is pressed, enabled, focused, selected and its window
   1236      * has the focus.
   1237      *
   1238      * @see #PRESSED_STATE_SET
   1239      * @see #ENABLED_STATE_SET
   1240      * @see #SELECTED_STATE_SET
   1241      * @see #FOCUSED_STATE_SET
   1242      * @see #WINDOW_FOCUSED_STATE_SET
   1243      */
   1244     protected static final int[] PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
   1245             stateSetUnion(PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
   1246 
   1247     /**
   1248      * The order here is very important to {@link #getDrawableState()}
   1249      */
   1250     private static final int[][] VIEW_STATE_SETS = {
   1251         EMPTY_STATE_SET,                                           // 0 0 0 0 0
   1252         WINDOW_FOCUSED_STATE_SET,                                  // 0 0 0 0 1
   1253         SELECTED_STATE_SET,                                        // 0 0 0 1 0
   1254         SELECTED_WINDOW_FOCUSED_STATE_SET,                         // 0 0 0 1 1
   1255         FOCUSED_STATE_SET,                                         // 0 0 1 0 0
   1256         FOCUSED_WINDOW_FOCUSED_STATE_SET,                          // 0 0 1 0 1
   1257         FOCUSED_SELECTED_STATE_SET,                                // 0 0 1 1 0
   1258         FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET,                 // 0 0 1 1 1
   1259         ENABLED_STATE_SET,                                         // 0 1 0 0 0
   1260         ENABLED_WINDOW_FOCUSED_STATE_SET,                          // 0 1 0 0 1
   1261         ENABLED_SELECTED_STATE_SET,                                // 0 1 0 1 0
   1262         ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET,                 // 0 1 0 1 1
   1263         ENABLED_FOCUSED_STATE_SET,                                 // 0 1 1 0 0
   1264         ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET,                  // 0 1 1 0 1
   1265         ENABLED_FOCUSED_SELECTED_STATE_SET,                        // 0 1 1 1 0
   1266         ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET,         // 0 1 1 1 1
   1267         PRESSED_STATE_SET,                                         // 1 0 0 0 0
   1268         PRESSED_WINDOW_FOCUSED_STATE_SET,                          // 1 0 0 0 1
   1269         PRESSED_SELECTED_STATE_SET,                                // 1 0 0 1 0
   1270         PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET,                 // 1 0 0 1 1
   1271         PRESSED_FOCUSED_STATE_SET,                                 // 1 0 1 0 0
   1272         PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET,                  // 1 0 1 0 1
   1273         PRESSED_FOCUSED_SELECTED_STATE_SET,                        // 1 0 1 1 0
   1274         PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET,         // 1 0 1 1 1
   1275         PRESSED_ENABLED_STATE_SET,                                 // 1 1 0 0 0
   1276         PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET,                  // 1 1 0 0 1
   1277         PRESSED_ENABLED_SELECTED_STATE_SET,                        // 1 1 0 1 0
   1278         PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET,         // 1 1 0 1 1
   1279         PRESSED_ENABLED_FOCUSED_STATE_SET,                         // 1 1 1 0 0
   1280         PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET,          // 1 1 1 0 1
   1281         PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET,                // 1 1 1 1 0
   1282         PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, // 1 1 1 1 1
   1283     };
   1284 
   1285     /**
   1286      * Used by views that contain lists of items. This state indicates that
   1287      * the view is showing the last item.
   1288      * @hide
   1289      */
   1290     protected static final int[] LAST_STATE_SET = {R.attr.state_last};
   1291     /**
   1292      * Used by views that contain lists of items. This state indicates that
   1293      * the view is showing the first item.
   1294      * @hide
   1295      */
   1296     protected static final int[] FIRST_STATE_SET = {R.attr.state_first};
   1297     /**
   1298      * Used by views that contain lists of items. This state indicates that
   1299      * the view is showing the middle item.
   1300      * @hide
   1301      */
   1302     protected static final int[] MIDDLE_STATE_SET = {R.attr.state_middle};
   1303     /**
   1304      * Used by views that contain lists of items. This state indicates that
   1305      * the view is showing only one item.
   1306      * @hide
   1307      */
   1308     protected static final int[] SINGLE_STATE_SET = {R.attr.state_single};
   1309     /**
   1310      * Used by views that contain lists of items. This state indicates that
   1311      * the view is pressed and showing the last item.
   1312      * @hide
   1313      */
   1314     protected static final int[] PRESSED_LAST_STATE_SET = {R.attr.state_last, R.attr.state_pressed};
   1315     /**
   1316      * Used by views that contain lists of items. This state indicates that
   1317      * the view is pressed and showing the first item.
   1318      * @hide
   1319      */
   1320     protected static final int[] PRESSED_FIRST_STATE_SET = {R.attr.state_first, R.attr.state_pressed};
   1321     /**
   1322      * Used by views that contain lists of items. This state indicates that
   1323      * the view is pressed and showing the middle item.
   1324      * @hide
   1325      */
   1326     protected static final int[] PRESSED_MIDDLE_STATE_SET = {R.attr.state_middle, R.attr.state_pressed};
   1327     /**
   1328      * Used by views that contain lists of items. This state indicates that
   1329      * the view is pressed and showing only one item.
   1330      * @hide
   1331      */
   1332     protected static final int[] PRESSED_SINGLE_STATE_SET = {R.attr.state_single, R.attr.state_pressed};
   1333 
   1334     /**
   1335      * Temporary Rect currently for use in setBackground().  This will probably
   1336      * be extended in the future to hold our own class with more than just
   1337      * a Rect. :)
   1338      */
   1339     static final ThreadLocal<Rect> sThreadLocal = new ThreadLocal<Rect>();
   1340 
   1341     /**
   1342      * Map used to store views' tags.
   1343      */
   1344     private static WeakHashMap<View, SparseArray<Object>> sTags;
   1345 
   1346     /**
   1347      * Lock used to access sTags.
   1348      */
   1349     private static final Object sTagsLock = new Object();
   1350 
   1351     /**
   1352      * The animation currently associated with this view.
   1353      * @hide
   1354      */
   1355     protected Animation mCurrentAnimation = null;
   1356 
   1357     /**
   1358      * Width as measured during measure pass.
   1359      * {@hide}
   1360      */
   1361     @ViewDebug.ExportedProperty
   1362     protected int mMeasuredWidth;
   1363 
   1364     /**
   1365      * Height as measured during measure pass.
   1366      * {@hide}
   1367      */
   1368     @ViewDebug.ExportedProperty
   1369     protected int mMeasuredHeight;
   1370 
   1371     /**
   1372      * The view's identifier.
   1373      * {@hide}
   1374      *
   1375      * @see #setId(int)
   1376      * @see #getId()
   1377      */
   1378     @ViewDebug.ExportedProperty(resolveId = true)
   1379     int mID = NO_ID;
   1380 
   1381     /**
   1382      * The view's tag.
   1383      * {@hide}
   1384      *
   1385      * @see #setTag(Object)
   1386      * @see #getTag()
   1387      */
   1388     protected Object mTag;
   1389 
   1390     // for mPrivateFlags:
   1391     /** {@hide} */
   1392     static final int WANTS_FOCUS                    = 0x00000001;
   1393     /** {@hide} */
   1394     static final int FOCUSED                        = 0x00000002;
   1395     /** {@hide} */
   1396     static final int SELECTED                       = 0x00000004;
   1397     /** {@hide} */
   1398     static final int IS_ROOT_NAMESPACE              = 0x00000008;
   1399     /** {@hide} */
   1400     static final int HAS_BOUNDS                     = 0x00000010;
   1401     /** {@hide} */
   1402     static final int DRAWN                          = 0x00000020;
   1403     /**
   1404      * When this flag is set, this view is running an animation on behalf of its
   1405      * children and should therefore not cancel invalidate requests, even if they
   1406      * lie outside of this view's bounds.
   1407      *
   1408      * {@hide}
   1409      */
   1410     static final int DRAW_ANIMATION                 = 0x00000040;
   1411     /** {@hide} */
   1412     static final int SKIP_DRAW                      = 0x00000080;
   1413     /** {@hide} */
   1414     static final int ONLY_DRAWS_BACKGROUND          = 0x00000100;
   1415     /** {@hide} */
   1416     static final int REQUEST_TRANSPARENT_REGIONS    = 0x00000200;
   1417     /** {@hide} */
   1418     static final int DRAWABLE_STATE_DIRTY           = 0x00000400;
   1419     /** {@hide} */
   1420     static final int MEASURED_DIMENSION_SET         = 0x00000800;
   1421     /** {@hide} */
   1422     static final int FORCE_LAYOUT                   = 0x00001000;
   1423 
   1424     private static final int LAYOUT_REQUIRED        = 0x00002000;
   1425 
   1426     private static final int PRESSED                = 0x00004000;
   1427 
   1428     /** {@hide} */
   1429     static final int DRAWING_CACHE_VALID            = 0x00008000;
   1430     /**
   1431      * Flag used to indicate that this view should be drawn once more (and only once
   1432      * more) after its animation has completed.
   1433      * {@hide}
   1434      */
   1435     static final int ANIMATION_STARTED              = 0x00010000;
   1436 
   1437     private static final int SAVE_STATE_CALLED      = 0x00020000;
   1438 
   1439     /**
   1440      * Indicates that the View returned true when onSetAlpha() was called and that
   1441      * the alpha must be restored.
   1442      * {@hide}
   1443      */
   1444     static final int ALPHA_SET                      = 0x00040000;
   1445 
   1446     /**
   1447      * Set by {@link #setScrollContainer(boolean)}.
   1448      */
   1449     static final int SCROLL_CONTAINER               = 0x00080000;
   1450 
   1451     /**
   1452      * Set by {@link #setScrollContainer(boolean)}.
   1453      */
   1454     static final int SCROLL_CONTAINER_ADDED         = 0x00100000;
   1455 
   1456     /**
   1457      * View flag indicating whether this view was invalidated (fully or partially.)
   1458      *
   1459      * @hide
   1460      */
   1461     static final int DIRTY                          = 0x00200000;
   1462 
   1463     /**
   1464      * View flag indicating whether this view was invalidated by an opaque
   1465      * invalidate request.
   1466      *
   1467      * @hide
   1468      */
   1469     static final int DIRTY_OPAQUE                   = 0x00400000;
   1470 
   1471     /**
   1472      * Mask for {@link #DIRTY} and {@link #DIRTY_OPAQUE}.
   1473      *
   1474      * @hide
   1475      */
   1476     static final int DIRTY_MASK                     = 0x00600000;
   1477 
   1478     /**
   1479      * Indicates whether the background is opaque.
   1480      *
   1481      * @hide
   1482      */
   1483     static final int OPAQUE_BACKGROUND              = 0x00800000;
   1484 
   1485     /**
   1486      * Indicates whether the scrollbars are opaque.
   1487      *
   1488      * @hide
   1489      */
   1490     static final int OPAQUE_SCROLLBARS              = 0x01000000;
   1491 
   1492     /**
   1493      * Indicates whether the view is opaque.
   1494      *
   1495      * @hide
   1496      */
   1497     static final int OPAQUE_MASK                    = 0x01800000;
   1498 
   1499     /**
   1500      * Indicates a prepressed state;
   1501      * the short time between ACTION_DOWN and recognizing
   1502      * a 'real' press. Prepressed is used to recognize quick taps
   1503      * even when they are shorter than ViewConfiguration.getTapTimeout().
   1504      *
   1505      * @hide
   1506      */
   1507     private static final int PREPRESSED             = 0x02000000;
   1508 
   1509     /**
   1510      * Indicates whether the view is temporarily detached.
   1511      *
   1512      * @hide
   1513      */
   1514     static final int CANCEL_NEXT_UP_EVENT = 0x04000000;
   1515 
   1516     /**
   1517      * Indicates that we should awaken scroll bars once attached
   1518      *
   1519      * @hide
   1520      */
   1521     private static final int AWAKEN_SCROLL_BARS_ON_ATTACH = 0x08000000;
   1522 
   1523     /**
   1524      * The parent this view is attached to.
   1525      * {@hide}
   1526      *
   1527      * @see #getParent()
   1528      */
   1529     protected ViewParent mParent;
   1530 
   1531     /**
   1532      * {@hide}
   1533      */
   1534     AttachInfo mAttachInfo;
   1535 
   1536     /**
   1537      * {@hide}
   1538      */
   1539     @ViewDebug.ExportedProperty(flagMapping = {
   1540         @ViewDebug.FlagToString(mask = FORCE_LAYOUT, equals = FORCE_LAYOUT,
   1541                 name = "FORCE_LAYOUT"),
   1542         @ViewDebug.FlagToString(mask = LAYOUT_REQUIRED, equals = LAYOUT_REQUIRED,
   1543                 name = "LAYOUT_REQUIRED"),
   1544         @ViewDebug.FlagToString(mask = DRAWING_CACHE_VALID, equals = DRAWING_CACHE_VALID,
   1545             name = "DRAWING_CACHE_INVALID", outputIf = false),
   1546         @ViewDebug.FlagToString(mask = DRAWN, equals = DRAWN, name = "DRAWN", outputIf = true),
   1547         @ViewDebug.FlagToString(mask = DRAWN, equals = DRAWN, name = "NOT_DRAWN", outputIf = false),
   1548         @ViewDebug.FlagToString(mask = DIRTY_MASK, equals = DIRTY_OPAQUE, name = "DIRTY_OPAQUE"),
   1549         @ViewDebug.FlagToString(mask = DIRTY_MASK, equals = DIRTY, name = "DIRTY")
   1550     })
   1551     int mPrivateFlags;
   1552 
   1553     /**
   1554      * Count of how many windows this view has been attached to.
   1555      */
   1556     int mWindowAttachCount;
   1557 
   1558     /**
   1559      * The layout parameters associated with this view and used by the parent
   1560      * {@link android.view.ViewGroup} to determine how this view should be
   1561      * laid out.
   1562      * {@hide}
   1563      */
   1564     protected ViewGroup.LayoutParams mLayoutParams;
   1565 
   1566     /**
   1567      * The view flags hold various views states.
   1568      * {@hide}
   1569      */
   1570     @ViewDebug.ExportedProperty
   1571     int mViewFlags;
   1572 
   1573     /**
   1574      * The distance in pixels from the left edge of this view's parent
   1575      * to the left edge of this view.
   1576      * {@hide}
   1577      */
   1578     @ViewDebug.ExportedProperty
   1579     protected int mLeft;
   1580     /**
   1581      * The distance in pixels from the left edge of this view's parent
   1582      * to the right edge of this view.
   1583      * {@hide}
   1584      */
   1585     @ViewDebug.ExportedProperty
   1586     protected int mRight;
   1587     /**
   1588      * The distance in pixels from the top edge of this view's parent
   1589      * to the top edge of this view.
   1590      * {@hide}
   1591      */
   1592     @ViewDebug.ExportedProperty
   1593     protected int mTop;
   1594     /**
   1595      * The distance in pixels from the top edge of this view's parent
   1596      * to the bottom edge of this view.
   1597      * {@hide}
   1598      */
   1599     @ViewDebug.ExportedProperty
   1600     protected int mBottom;
   1601 
   1602     /**
   1603      * The offset, in pixels, by which the content of this view is scrolled
   1604      * horizontally.
   1605      * {@hide}
   1606      */
   1607     @ViewDebug.ExportedProperty
   1608     protected int mScrollX;
   1609     /**
   1610      * The offset, in pixels, by which the content of this view is scrolled
   1611      * vertically.
   1612      * {@hide}
   1613      */
   1614     @ViewDebug.ExportedProperty
   1615     protected int mScrollY;
   1616 
   1617     /**
   1618      * The left padding in pixels, that is the distance in pixels between the
   1619      * left edge of this view and the left edge of its content.
   1620      * {@hide}
   1621      */
   1622     @ViewDebug.ExportedProperty
   1623     protected int mPaddingLeft;
   1624     /**
   1625      * The right padding in pixels, that is the distance in pixels between the
   1626      * right edge of this view and the right edge of its content.
   1627      * {@hide}
   1628      */
   1629     @ViewDebug.ExportedProperty
   1630     protected int mPaddingRight;
   1631     /**
   1632      * The top padding in pixels, that is the distance in pixels between the
   1633      * top edge of this view and the top edge of its content.
   1634      * {@hide}
   1635      */
   1636     @ViewDebug.ExportedProperty
   1637     protected int mPaddingTop;
   1638     /**
   1639      * The bottom padding in pixels, that is the distance in pixels between the
   1640      * bottom edge of this view and the bottom edge of its content.
   1641      * {@hide}
   1642      */
   1643     @ViewDebug.ExportedProperty
   1644     protected int mPaddingBottom;
   1645 
   1646     /**
   1647      * Briefly describes the view and is primarily used for accessibility support.
   1648      */
   1649     private CharSequence mContentDescription;
   1650 
   1651     /**
   1652      * Cache the paddingRight set by the user to append to the scrollbar's size.
   1653      */
   1654     @ViewDebug.ExportedProperty
   1655     int mUserPaddingRight;
   1656 
   1657     /**
   1658      * Cache the paddingBottom set by the user to append to the scrollbar's size.
   1659      */
   1660     @ViewDebug.ExportedProperty
   1661     int mUserPaddingBottom;
   1662 
   1663     /**
   1664      * @hide
   1665      */
   1666     int mOldWidthMeasureSpec = Integer.MIN_VALUE;
   1667     /**
   1668      * @hide
   1669      */
   1670     int mOldHeightMeasureSpec = Integer.MIN_VALUE;
   1671 
   1672     private Resources mResources = null;
   1673 
   1674     private Drawable mBGDrawable;
   1675 
   1676     private int mBackgroundResource;
   1677     private boolean mBackgroundSizeChanged;
   1678 
   1679     /**
   1680      * Listener used to dispatch focus change events.
   1681      * This field should be made private, so it is hidden from the SDK.
   1682      * {@hide}
   1683      */
   1684     protected OnFocusChangeListener mOnFocusChangeListener;
   1685 
   1686     /**
   1687      * Listener used to dispatch click events.
   1688      * This field should be made private, so it is hidden from the SDK.
   1689      * {@hide}
   1690      */
   1691     protected OnClickListener mOnClickListener;
   1692 
   1693     /**
   1694      * Listener used to dispatch long click events.
   1695      * This field should be made private, so it is hidden from the SDK.
   1696      * {@hide}
   1697      */
   1698     protected OnLongClickListener mOnLongClickListener;
   1699 
   1700     /**
   1701      * Listener used to build the context menu.
   1702      * This field should be made private, so it is hidden from the SDK.
   1703      * {@hide}
   1704      */
   1705     protected OnCreateContextMenuListener mOnCreateContextMenuListener;
   1706 
   1707     private OnKeyListener mOnKeyListener;
   1708 
   1709     private OnTouchListener mOnTouchListener;
   1710 
   1711     /**
   1712      * The application environment this view lives in.
   1713      * This field should be made private, so it is hidden from the SDK.
   1714      * {@hide}
   1715      */
   1716     protected Context mContext;
   1717 
   1718     private ScrollabilityCache mScrollCache;
   1719 
   1720     private int[] mDrawableState = null;
   1721 
   1722     private SoftReference<Bitmap> mDrawingCache;
   1723     private SoftReference<Bitmap> mUnscaledDrawingCache;
   1724 
   1725     /**
   1726      * When this view has focus and the next focus is {@link #FOCUS_LEFT},
   1727      * the user may specify which view to go to next.
   1728      */
   1729     private int mNextFocusLeftId = View.NO_ID;
   1730 
   1731     /**
   1732      * When this view has focus and the next focus is {@link #FOCUS_RIGHT},
   1733      * the user may specify which view to go to next.
   1734      */
   1735     private int mNextFocusRightId = View.NO_ID;
   1736 
   1737     /**
   1738      * When this view has focus and the next focus is {@link #FOCUS_UP},
   1739      * the user may specify which view to go to next.
   1740      */
   1741     private int mNextFocusUpId = View.NO_ID;
   1742 
   1743     /**
   1744      * When this view has focus and the next focus is {@link #FOCUS_DOWN},
   1745      * the user may specify which view to go to next.
   1746      */
   1747     private int mNextFocusDownId = View.NO_ID;
   1748 
   1749     private CheckForLongPress mPendingCheckForLongPress;
   1750     private CheckForTap mPendingCheckForTap = null;
   1751     private PerformClick mPerformClick;
   1752 
   1753     private UnsetPressedState mUnsetPressedState;
   1754 
   1755     /**
   1756      * Whether the long press's action has been invoked.  The tap's action is invoked on the
   1757      * up event while a long press is invoked as soon as the long press duration is reached, so
   1758      * a long press could be performed before the tap is checked, in which case the tap's action
   1759      * should not be invoked.
   1760      */
   1761     private boolean mHasPerformedLongPress;
   1762 
   1763     /**
   1764      * The minimum height of the view. We'll try our best to have the height
   1765      * of this view to at least this amount.
   1766      */
   1767     @ViewDebug.ExportedProperty
   1768     private int mMinHeight;
   1769 
   1770     /**
   1771      * The minimum width of the view. We'll try our best to have the width
   1772      * of this view to at least this amount.
   1773      */
   1774     @ViewDebug.ExportedProperty
   1775     private int mMinWidth;
   1776 
   1777     /**
   1778      * The delegate to handle touch events that are physically in this view
   1779      * but should be handled by another view.
   1780      */
   1781     private TouchDelegate mTouchDelegate = null;
   1782 
   1783     /**
   1784      * Solid color to use as a background when creating the drawing cache. Enables
   1785      * the cache to use 16 bit bitmaps instead of 32 bit.
   1786      */
   1787     private int mDrawingCacheBackgroundColor = 0;
   1788 
   1789     /**
   1790      * Special tree observer used when mAttachInfo is null.
   1791      */
   1792     private ViewTreeObserver mFloatingTreeObserver;
   1793 
   1794     /**
   1795      * Cache the touch slop from the context that created the view.
   1796      */
   1797     private int mTouchSlop;
   1798 
   1799     // Used for debug only
   1800     static long sInstanceCount = 0;
   1801 
   1802     /**
   1803      * Simple constructor to use when creating a view from code.
   1804      *
   1805      * @param context The Context the view is running in, through which it can
   1806      *        access the current theme, resources, etc.
   1807      */
   1808     public View(Context context) {
   1809         mContext = context;
   1810         mResources = context != null ? context.getResources() : null;
   1811         mViewFlags = SOUND_EFFECTS_ENABLED | HAPTIC_FEEDBACK_ENABLED;
   1812         // Used for debug only
   1813         //++sInstanceCount;
   1814         mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
   1815     }
   1816 
   1817     /**
   1818      * Constructor that is called when inflating a view from XML. This is called
   1819      * when a view is being constructed from an XML file, supplying attributes
   1820      * that were specified in the XML file. This version uses a default style of
   1821      * 0, so the only attribute values applied are those in the Context's Theme
   1822      * and the given AttributeSet.
   1823      *
   1824      * <p>
   1825      * The method onFinishInflate() will be called after all children have been
   1826      * added.
   1827      *
   1828      * @param context The Context the view is running in, through which it can
   1829      *        access the current theme, resources, etc.
   1830      * @param attrs The attributes of the XML tag that is inflating the view.
   1831      * @see #View(Context, AttributeSet, int)
   1832      */
   1833     public View(Context context, AttributeSet attrs) {
   1834         this(context, attrs, 0);
   1835     }
   1836 
   1837     /**
   1838      * Perform inflation from XML and apply a class-specific base style. This
   1839      * constructor of View allows subclasses to use their own base style when
   1840      * they are inflating. For example, a Button class's constructor would call
   1841      * this version of the super class constructor and supply
   1842      * <code>R.attr.buttonStyle</code> for <var>defStyle</var>; this allows
   1843      * the theme's button style to modify all of the base view attributes (in
   1844      * particular its background) as well as the Button class's attributes.
   1845      *
   1846      * @param context The Context the view is running in, through which it can
   1847      *        access the current theme, resources, etc.
   1848      * @param attrs The attributes of the XML tag that is inflating the view.
   1849      * @param defStyle The default style to apply to this view. If 0, no style
   1850      *        will be applied (beyond what is included in the theme). This may
   1851      *        either be an attribute resource, whose value will be retrieved
   1852      *        from the current theme, or an explicit style resource.
   1853      * @see #View(Context, AttributeSet)
   1854      */
   1855     public View(Context context, AttributeSet attrs, int defStyle) {
   1856         this(context);
   1857 
   1858         TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.View,
   1859                 defStyle, 0);
   1860 
   1861         Drawable background = null;
   1862 
   1863         int leftPadding = -1;
   1864         int topPadding = -1;
   1865         int rightPadding = -1;
   1866         int bottomPadding = -1;
   1867 
   1868         int padding = -1;
   1869 
   1870         int viewFlagValues = 0;
   1871         int viewFlagMasks = 0;
   1872 
   1873         boolean setScrollContainer = false;
   1874 
   1875         int x = 0;
   1876         int y = 0;
   1877 
   1878         int scrollbarStyle = SCROLLBARS_INSIDE_OVERLAY;
   1879 
   1880         final int N = a.getIndexCount();
   1881         for (int i = 0; i < N; i++) {
   1882             int attr = a.getIndex(i);
   1883             switch (attr) {
   1884                 case com.android.internal.R.styleable.View_background:
   1885                     background = a.getDrawable(attr);
   1886                     break;
   1887                 case com.android.internal.R.styleable.View_padding:
   1888                     padding = a.getDimensionPixelSize(attr, -1);
   1889                     break;
   1890                  case com.android.internal.R.styleable.View_paddingLeft:
   1891                     leftPadding = a.getDimensionPixelSize(attr, -1);
   1892                     break;
   1893                 case com.android.internal.R.styleable.View_paddingTop:
   1894                     topPadding = a.getDimensionPixelSize(attr, -1);
   1895                     break;
   1896                 case com.android.internal.R.styleable.View_paddingRight:
   1897                     rightPadding = a.getDimensionPixelSize(attr, -1);
   1898                     break;
   1899                 case com.android.internal.R.styleable.View_paddingBottom:
   1900                     bottomPadding = a.getDimensionPixelSize(attr, -1);
   1901                     break;
   1902                 case com.android.internal.R.styleable.View_scrollX:
   1903                     x = a.getDimensionPixelOffset(attr, 0);
   1904                     break;
   1905                 case com.android.internal.R.styleable.View_scrollY:
   1906                     y = a.getDimensionPixelOffset(attr, 0);
   1907                     break;
   1908                 case com.android.internal.R.styleable.View_id:
   1909                     mID = a.getResourceId(attr, NO_ID);
   1910                     break;
   1911                 case com.android.internal.R.styleable.View_tag:
   1912                     mTag = a.getText(attr);
   1913                     break;
   1914                 case com.android.internal.R.styleable.View_fitsSystemWindows:
   1915                     if (a.getBoolean(attr, false)) {
   1916                         viewFlagValues |= FITS_SYSTEM_WINDOWS;
   1917                         viewFlagMasks |= FITS_SYSTEM_WINDOWS;
   1918                     }
   1919                     break;
   1920                 case com.android.internal.R.styleable.View_focusable:
   1921                     if (a.getBoolean(attr, false)) {
   1922                         viewFlagValues |= FOCUSABLE;
   1923                         viewFlagMasks |= FOCUSABLE_MASK;
   1924                     }
   1925                     break;
   1926                 case com.android.internal.R.styleable.View_focusableInTouchMode:
   1927                     if (a.getBoolean(attr, false)) {
   1928                         viewFlagValues |= FOCUSABLE_IN_TOUCH_MODE | FOCUSABLE;
   1929                         viewFlagMasks |= FOCUSABLE_IN_TOUCH_MODE | FOCUSABLE_MASK;
   1930                     }
   1931                     break;
   1932                 case com.android.internal.R.styleable.View_clickable:
   1933                     if (a.getBoolean(attr, false)) {
   1934                         viewFlagValues |= CLICKABLE;
   1935                         viewFlagMasks |= CLICKABLE;
   1936                     }
   1937                     break;
   1938                 case com.android.internal.R.styleable.View_longClickable:
   1939                     if (a.getBoolean(attr, false)) {
   1940                         viewFlagValues |= LONG_CLICKABLE;
   1941                         viewFlagMasks |= LONG_CLICKABLE;
   1942                     }
   1943                     break;
   1944                 case com.android.internal.R.styleable.View_saveEnabled:
   1945                     if (!a.getBoolean(attr, true)) {
   1946                         viewFlagValues |= SAVE_DISABLED;
   1947                         viewFlagMasks |= SAVE_DISABLED_MASK;
   1948                     }
   1949                     break;
   1950                 case com.android.internal.R.styleable.View_duplicateParentState:
   1951                     if (a.getBoolean(attr, false)) {
   1952                         viewFlagValues |= DUPLICATE_PARENT_STATE;
   1953                         viewFlagMasks |= DUPLICATE_PARENT_STATE;
   1954                     }
   1955                     break;
   1956                 case com.android.internal.R.styleable.View_visibility:
   1957                     final int visibility = a.getInt(attr, 0);
   1958                     if (visibility != 0) {
   1959                         viewFlagValues |= VISIBILITY_FLAGS[visibility];
   1960                         viewFlagMasks |= VISIBILITY_MASK;
   1961                     }
   1962                     break;
   1963                 case com.android.internal.R.styleable.View_drawingCacheQuality:
   1964                     final int cacheQuality = a.getInt(attr, 0);
   1965                     if (cacheQuality != 0) {
   1966                         viewFlagValues |= DRAWING_CACHE_QUALITY_FLAGS[cacheQuality];
   1967                         viewFlagMasks |= DRAWING_CACHE_QUALITY_MASK;
   1968                     }
   1969                     break;
   1970                 case com.android.internal.R.styleable.View_contentDescription:
   1971                     mContentDescription = a.getString(attr);
   1972                     break;
   1973                 case com.android.internal.R.styleable.View_soundEffectsEnabled:
   1974                     if (!a.getBoolean(attr, true)) {
   1975                         viewFlagValues &= ~SOUND_EFFECTS_ENABLED;
   1976                         viewFlagMasks |= SOUND_EFFECTS_ENABLED;
   1977                     }
   1978                     break;
   1979                 case com.android.internal.R.styleable.View_hapticFeedbackEnabled:
   1980                     if (!a.getBoolean(attr, true)) {
   1981                         viewFlagValues &= ~HAPTIC_FEEDBACK_ENABLED;
   1982                         viewFlagMasks |= HAPTIC_FEEDBACK_ENABLED;
   1983                     }
   1984                     break;
   1985                 case R.styleable.View_scrollbars:
   1986                     final int scrollbars = a.getInt(attr, SCROLLBARS_NONE);
   1987                     if (scrollbars != SCROLLBARS_NONE) {
   1988                         viewFlagValues |= scrollbars;
   1989                         viewFlagMasks |= SCROLLBARS_MASK;
   1990                         initializeScrollbars(a);
   1991                     }
   1992                     break;
   1993                 case R.styleable.View_fadingEdge:
   1994                     final int fadingEdge = a.getInt(attr, FADING_EDGE_NONE);
   1995                     if (fadingEdge != FADING_EDGE_NONE) {
   1996                         viewFlagValues |= fadingEdge;
   1997                         viewFlagMasks |= FADING_EDGE_MASK;
   1998                         initializeFadingEdge(a);
   1999                     }
   2000                     break;
   2001                 case R.styleable.View_scrollbarStyle:
   2002                     scrollbarStyle = a.getInt(attr, SCROLLBARS_INSIDE_OVERLAY);
   2003                     if (scrollbarStyle != SCROLLBARS_INSIDE_OVERLAY) {
   2004                         viewFlagValues |= scrollbarStyle & SCROLLBARS_STYLE_MASK;
   2005                         viewFlagMasks |= SCROLLBARS_STYLE_MASK;
   2006                     }
   2007                     break;
   2008                 case R.styleable.View_isScrollContainer:
   2009                     setScrollContainer = true;
   2010                     if (a.getBoolean(attr, false)) {
   2011                         setScrollContainer(true);
   2012                     }
   2013                     break;
   2014                 case com.android.internal.R.styleable.View_keepScreenOn:
   2015                     if (a.getBoolean(attr, false)) {
   2016                         viewFlagValues |= KEEP_SCREEN_ON;
   2017                         viewFlagMasks |= KEEP_SCREEN_ON;
   2018                     }
   2019                     break;
   2020                 case R.styleable.View_nextFocusLeft:
   2021                     mNextFocusLeftId = a.getResourceId(attr, View.NO_ID);
   2022                     break;
   2023                 case R.styleable.View_nextFocusRight:
   2024                     mNextFocusRightId = a.getResourceId(attr, View.NO_ID);
   2025                     break;
   2026                 case R.styleable.View_nextFocusUp:
   2027                     mNextFocusUpId = a.getResourceId(attr, View.NO_ID);
   2028                     break;
   2029                 case R.styleable.View_nextFocusDown:
   2030                     mNextFocusDownId = a.getResourceId(attr, View.NO_ID);
   2031                     break;
   2032                 case R.styleable.View_minWidth:
   2033                     mMinWidth = a.getDimensionPixelSize(attr, 0);
   2034                     break;
   2035                 case R.styleable.View_minHeight:
   2036                     mMinHeight = a.getDimensionPixelSize(attr, 0);
   2037                     break;
   2038                 case R.styleable.View_onClick:
   2039                     if (context.isRestricted()) {
   2040                         throw new IllegalStateException("The android:onClick attribute cannot "
   2041                                 + "be used within a restricted context");
   2042                     }
   2043 
   2044                     final String handlerName = a.getString(attr);
   2045                     if (handlerName != null) {
   2046                         setOnClickListener(new OnClickListener() {
   2047                             private Method mHandler;
   2048 
   2049                             public void onClick(View v) {
   2050                                 if (mHandler == null) {
   2051                                     try {
   2052                                         mHandler = getContext().getClass().getMethod(handlerName,
   2053                                                 View.class);
   2054                                     } catch (NoSuchMethodException e) {
   2055                                         int id = getId();
   2056                                         String idText = id == NO_ID ? "" : " with id '"
   2057                                                 + getContext().getResources().getResourceEntryName(
   2058                                                     id) + "'";
   2059                                         throw new IllegalStateException("Could not find a method " +
   2060                                                 handlerName + "(View) in the activity "
   2061                                                 + getContext().getClass() + " for onClick handler"
   2062                                                 + " on view " + View.this.getClass() + idText, e);
   2063                                     }
   2064                                 }
   2065 
   2066                                 try {
   2067                                     mHandler.invoke(getContext(), View.this);
   2068                                 } catch (IllegalAccessException e) {
   2069                                     throw new IllegalStateException("Could not execute non "
   2070                                             + "public method of the activity", e);
   2071                                 } catch (InvocationTargetException e) {
   2072                                     throw new IllegalStateException("Could not execute "
   2073                                             + "method of the activity", e);
   2074                                 }
   2075                             }
   2076                         });
   2077                     }
   2078                     break;
   2079             }
   2080         }
   2081 
   2082         if (background != null) {
   2083             setBackgroundDrawable(background);
   2084         }
   2085 
   2086         if (padding >= 0) {
   2087             leftPadding = padding;
   2088             topPadding = padding;
   2089             rightPadding = padding;
   2090             bottomPadding = padding;
   2091         }
   2092 
   2093         // If the user specified the padding (either with android:padding or
   2094         // android:paddingLeft/Top/Right/Bottom), use this padding, otherwise
   2095         // use the default padding or the padding from the background drawable
   2096         // (stored at this point in mPadding*)
   2097         setPadding(leftPadding >= 0 ? leftPadding : mPaddingLeft,
   2098                 topPadding >= 0 ? topPadding : mPaddingTop,
   2099                 rightPadding >= 0 ? rightPadding : mPaddingRight,
   2100                 bottomPadding >= 0 ? bottomPadding : mPaddingBottom);
   2101 
   2102         if (viewFlagMasks != 0) {
   2103             setFlags(viewFlagValues, viewFlagMasks);
   2104         }
   2105 
   2106         // Needs to be called after mViewFlags is set
   2107         if (scrollbarStyle != SCROLLBARS_INSIDE_OVERLAY) {
   2108             recomputePadding();
   2109         }
   2110 
   2111         if (x != 0 || y != 0) {
   2112             scrollTo(x, y);
   2113         }
   2114 
   2115         if (!setScrollContainer && (viewFlagValues&SCROLLBARS_VERTICAL) != 0) {
   2116             setScrollContainer(true);
   2117         }
   2118 
   2119         computeOpaqueFlags();
   2120 
   2121         a.recycle();
   2122     }
   2123 
   2124     /**
   2125      * Non-public constructor for use in testing
   2126      */
   2127     View() {
   2128     }
   2129 
   2130     // Used for debug only
   2131     /*
   2132     @Override
   2133     protected void finalize() throws Throwable {
   2134         super.finalize();
   2135         --sInstanceCount;
   2136     }
   2137     */
   2138 
   2139     /**
   2140      * <p>
   2141      * Initializes the fading edges from a given set of styled attributes. This
   2142      * method should be called by subclasses that need fading edges and when an
   2143      * instance of these subclasses is created programmatically rather than
   2144      * being inflated from XML. This method is automatically called when the XML
   2145      * is inflated.
   2146      * </p>
   2147      *
   2148      * @param a the styled attributes set to initialize the fading edges from
   2149      */
   2150     protected void initializeFadingEdge(TypedArray a) {
   2151         initScrollCache();
   2152 
   2153         mScrollCache.fadingEdgeLength = a.getDimensionPixelSize(
   2154                 R.styleable.View_fadingEdgeLength,
   2155                 ViewConfiguration.get(mContext).getScaledFadingEdgeLength());
   2156     }
   2157 
   2158     /**
   2159      * Returns the size of the vertical faded edges used to indicate that more
   2160      * content in this view is visible.
   2161      *
   2162      * @return The size in pixels of the vertical faded edge or 0 if vertical
   2163      *         faded edges are not enabled for this view.
   2164      * @attr ref android.R.styleable#View_fadingEdgeLength
   2165      */
   2166     public int getVerticalFadingEdgeLength() {
   2167         if (isVerticalFadingEdgeEnabled()) {
   2168             ScrollabilityCache cache = mScrollCache;
   2169             if (cache != null) {
   2170                 return cache.fadingEdgeLength;
   2171             }
   2172         }
   2173         return 0;
   2174     }
   2175 
   2176     /**
   2177      * Set the size of the faded edge used to indicate that more content in this
   2178      * view is available.  Will not change whether the fading edge is enabled; use
   2179      * {@link #setVerticalFadingEdgeEnabled} or {@link #setHorizontalFadingEdgeEnabled}
   2180      * to enable the fading edge for the vertical or horizontal fading edges.
   2181      *
   2182      * @param length The size in pixels of the faded edge used to indicate that more
   2183      *        content in this view is visible.
   2184      */
   2185     public void setFadingEdgeLength(int length) {
   2186         initScrollCache();
   2187         mScrollCache.fadingEdgeLength = length;
   2188     }
   2189 
   2190     /**
   2191      * Returns the size of the horizontal faded edges used to indicate that more
   2192      * content in this view is visible.
   2193      *
   2194      * @return The size in pixels of the horizontal faded edge or 0 if horizontal
   2195      *         faded edges are not enabled for this view.
   2196      * @attr ref android.R.styleable#View_fadingEdgeLength
   2197      */
   2198     public int getHorizontalFadingEdgeLength() {
   2199         if (isHorizontalFadingEdgeEnabled()) {
   2200             ScrollabilityCache cache = mScrollCache;
   2201             if (cache != null) {
   2202                 return cache.fadingEdgeLength;
   2203             }
   2204         }
   2205         return 0;
   2206     }
   2207 
   2208     /**
   2209      * Returns the width of the vertical scrollbar.
   2210      *
   2211      * @return The width in pixels of the vertical scrollbar or 0 if there
   2212      *         is no vertical scrollbar.
   2213      */
   2214     public int getVerticalScrollbarWidth() {
   2215         ScrollabilityCache cache = mScrollCache;
   2216         if (cache != null) {
   2217             ScrollBarDrawable scrollBar = cache.scrollBar;
   2218             if (scrollBar != null) {
   2219                 int size = scrollBar.getSize(true);
   2220                 if (size <= 0) {
   2221                     size = cache.scrollBarSize;
   2222                 }
   2223                 return size;
   2224             }
   2225             return 0;
   2226         }
   2227         return 0;
   2228     }
   2229 
   2230     /**
   2231      * Returns the height of the horizontal scrollbar.
   2232      *
   2233      * @return The height in pixels of the horizontal scrollbar or 0 if
   2234      *         there is no horizontal scrollbar.
   2235      */
   2236     protected int getHorizontalScrollbarHeight() {
   2237         ScrollabilityCache cache = mScrollCache;
   2238         if (cache != null) {
   2239             ScrollBarDrawable scrollBar = cache.scrollBar;
   2240             if (scrollBar != null) {
   2241                 int size = scrollBar.getSize(false);
   2242                 if (size <= 0) {
   2243                     size = cache.scrollBarSize;
   2244                 }
   2245                 return size;
   2246             }
   2247             return 0;
   2248         }
   2249         return 0;
   2250     }
   2251 
   2252     /**
   2253      * <p>
   2254      * Initializes the scrollbars from a given set of styled attributes. This
   2255      * method should be called by subclasses that need scrollbars and when an
   2256      * instance of these subclasses is created programmatically rather than
   2257      * being inflated from XML. This method is automatically called when the XML
   2258      * is inflated.
   2259      * </p>
   2260      *
   2261      * @param a the styled attributes set to initialize the scrollbars from
   2262      */
   2263     protected void initializeScrollbars(TypedArray a) {
   2264         initScrollCache();
   2265 
   2266         final ScrollabilityCache scrollabilityCache = mScrollCache;
   2267 
   2268         if (scrollabilityCache.scrollBar == null) {
   2269             scrollabilityCache.scrollBar = new ScrollBarDrawable();
   2270         }
   2271 
   2272         final boolean fadeScrollbars = a.getBoolean(R.styleable.View_fadeScrollbars, true);
   2273 
   2274         if (!fadeScrollbars) {
   2275             scrollabilityCache.state = ScrollabilityCache.ON;
   2276         }
   2277         scrollabilityCache.fadeScrollBars = fadeScrollbars;
   2278 
   2279 
   2280         scrollabilityCache.scrollBarFadeDuration = a.getInt(
   2281                 R.styleable.View_scrollbarFadeDuration, ViewConfiguration
   2282                         .getScrollBarFadeDuration());
   2283         scrollabilityCache.scrollBarDefaultDelayBeforeFade = a.getInt(
   2284                 R.styleable.View_scrollbarDefaultDelayBeforeFade,
   2285                 ViewConfiguration.getScrollDefaultDelay());
   2286 
   2287 
   2288         scrollabilityCache.scrollBarSize = a.getDimensionPixelSize(
   2289                 com.android.internal.R.styleable.View_scrollbarSize,
   2290                 ViewConfiguration.get(mContext).getScaledScrollBarSize());
   2291 
   2292         Drawable track = a.getDrawable(R.styleable.View_scrollbarTrackHorizontal);
   2293         scrollabilityCache.scrollBar.setHorizontalTrackDrawable(track);
   2294 
   2295         Drawable thumb = a.getDrawable(R.styleable.View_scrollbarThumbHorizontal);
   2296         if (thumb != null) {
   2297             scrollabilityCache.scrollBar.setHorizontalThumbDrawable(thumb);
   2298         }
   2299 
   2300         boolean alwaysDraw = a.getBoolean(R.styleable.View_scrollbarAlwaysDrawHorizontalTrack,
   2301                 false);
   2302         if (alwaysDraw) {
   2303             scrollabilityCache.scrollBar.setAlwaysDrawHorizontalTrack(true);
   2304         }
   2305 
   2306         track = a.getDrawable(R.styleable.View_scrollbarTrackVertical);
   2307         scrollabilityCache.scrollBar.setVerticalTrackDrawable(track);
   2308 
   2309         thumb = a.getDrawable(R.styleable.View_scrollbarThumbVertical);
   2310         if (thumb != null) {
   2311             scrollabilityCache.scrollBar.setVerticalThumbDrawable(thumb);
   2312         }
   2313 
   2314         alwaysDraw = a.getBoolean(R.styleable.View_scrollbarAlwaysDrawVerticalTrack,
   2315                 false);
   2316         if (alwaysDraw) {
   2317             scrollabilityCache.scrollBar.setAlwaysDrawVerticalTrack(true);
   2318         }
   2319 
   2320         // Re-apply user/background padding so that scrollbar(s) get added
   2321         recomputePadding();
   2322     }
   2323 
   2324     /**
   2325      * <p>
   2326      * Initalizes the scrollability cache if necessary.
   2327      * </p>
   2328      */
   2329     private void initScrollCache() {
   2330         if (mScrollCache == null) {
   2331             mScrollCache = new ScrollabilityCache(ViewConfiguration.get(mContext), this);
   2332         }
   2333     }
   2334 
   2335     /**
   2336      * Register a callback to be invoked when focus of this view changed.
   2337      *
   2338      * @param l The callback that will run.
   2339      */
   2340     public void setOnFocusChangeListener(OnFocusChangeListener l) {
   2341         mOnFocusChangeListener = l;
   2342     }
   2343 
   2344     /**
   2345      * Returns the focus-change callback registered for this view.
   2346      *
   2347      * @return The callback, or null if one is not registered.
   2348      */
   2349     public OnFocusChangeListener getOnFocusChangeListener() {
   2350         return mOnFocusChangeListener;
   2351     }
   2352 
   2353     /**
   2354      * Register a callback to be invoked when this view is clicked. If this view is not
   2355      * clickable, it becomes clickable.
   2356      *
   2357      * @param l The callback that will run
   2358      *
   2359      * @see #setClickable(boolean)
   2360      */
   2361     public void setOnClickListener(OnClickListener l) {
   2362         if (!isClickable()) {
   2363             setClickable(true);
   2364         }
   2365         mOnClickListener = l;
   2366     }
   2367 
   2368     /**
   2369      * Register a callback to be invoked when this view is clicked and held. If this view is not
   2370      * long clickable, it becomes long clickable.
   2371      *
   2372      * @param l The callback that will run
   2373      *
   2374      * @see #setLongClickable(boolean)
   2375      */
   2376     public void setOnLongClickListener(OnLongClickListener l) {
   2377         if (!isLongClickable()) {
   2378             setLongClickable(true);
   2379         }
   2380         mOnLongClickListener = l;
   2381     }
   2382 
   2383     /**
   2384      * Register a callback to be invoked when the context menu for this view is
   2385      * being built. If this view is not long clickable, it becomes long clickable.
   2386      *
   2387      * @param l The callback that will run
   2388      *
   2389      */
   2390     public void setOnCreateContextMenuListener(OnCreateContextMenuListener l) {
   2391         if (!isLongClickable()) {
   2392             setLongClickable(true);
   2393         }
   2394         mOnCreateContextMenuListener = l;
   2395     }
   2396 
   2397     /**
   2398      * Call this view's OnClickListener, if it is defined.
   2399      *
   2400      * @return True there was an assigned OnClickListener that was called, false
   2401      *         otherwise is returned.
   2402      */
   2403     public boolean performClick() {
   2404         sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
   2405 
   2406         if (mOnClickListener != null) {
   2407             playSoundEffect(SoundEffectConstants.CLICK);
   2408             mOnClickListener.onClick(this);
   2409             return true;
   2410         }
   2411 
   2412         return false;
   2413     }
   2414 
   2415     /**
   2416      * Call this view's OnLongClickListener, if it is defined. Invokes the context menu
   2417      * if the OnLongClickListener did not consume the event.
   2418      *
   2419      * @return True there was an assigned OnLongClickListener that was called, false
   2420      *         otherwise is returned.
   2421      */
   2422     public boolean performLongClick() {
   2423         sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_LONG_CLICKED);
   2424 
   2425         boolean handled = false;
   2426         if (mOnLongClickListener != null) {
   2427             handled = mOnLongClickListener.onLongClick(View.this);
   2428         }
   2429         if (!handled) {
   2430             handled = showContextMenu();
   2431         }
   2432         if (handled) {
   2433             performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
   2434         }
   2435         return handled;
   2436     }
   2437 
   2438     /**
   2439      * Bring up the context menu for this view.
   2440      *
   2441      * @return Whether a context menu was displayed.
   2442      */
   2443     public boolean showContextMenu() {
   2444         return getParent().showContextMenuForChild(this);
   2445     }
   2446 
   2447     /**
   2448      * Register a callback to be invoked when a key is pressed in this view.
   2449      * @param l the key listener to attach to this view
   2450      */
   2451     public void setOnKeyListener(OnKeyListener l) {
   2452         mOnKeyListener = l;
   2453     }
   2454 
   2455     /**
   2456      * Register a callback to be invoked when a touch event is sent to this view.
   2457      * @param l the touch listener to attach to this view
   2458      */
   2459     public void setOnTouchListener(OnTouchListener l) {
   2460         mOnTouchListener = l;
   2461     }
   2462 
   2463     /**
   2464      * Give this view focus. This will cause {@link #onFocusChanged} to be called.
   2465      *
   2466      * Note: this does not check whether this {@link View} should get focus, it just
   2467      * gives it focus no matter what.  It should only be called internally by framework
   2468      * code that knows what it is doing, namely {@link #requestFocus(int, Rect)}.
   2469      *
   2470      * @param direction values are View.FOCUS_UP, View.FOCUS_DOWN,
   2471      *        View.FOCUS_LEFT or View.FOCUS_RIGHT. This is the direction which
   2472      *        focus moved when requestFocus() is called. It may not always
   2473      *        apply, in which case use the default View.FOCUS_DOWN.
   2474      * @param previouslyFocusedRect The rectangle of the view that had focus
   2475      *        prior in this View's coordinate system.
   2476      */
   2477     void handleFocusGainInternal(int direction, Rect previouslyFocusedRect) {
   2478         if (DBG) {
   2479             System.out.println(this + " requestFocus()");
   2480         }
   2481 
   2482         if ((mPrivateFlags & FOCUSED) == 0) {
   2483             mPrivateFlags |= FOCUSED;
   2484 
   2485             if (mParent != null) {
   2486                 mParent.requestChildFocus(this, this);
   2487             }
   2488 
   2489             onFocusChanged(true, direction, previouslyFocusedRect);
   2490             refreshDrawableState();
   2491         }
   2492     }
   2493 
   2494     /**
   2495      * Request that a rectangle of this view be visible on the screen,
   2496      * scrolling if necessary just enough.
   2497      *
   2498      * <p>A View should call this if it maintains some notion of which part
   2499      * of its content is interesting.  For example, a text editing view
   2500      * should call this when its cursor moves.
   2501      *
   2502      * @param rectangle The rectangle.
   2503      * @return Whether any parent scrolled.
   2504      */
   2505     public boolean requestRectangleOnScreen(Rect rectangle) {
   2506         return requestRectangleOnScreen(rectangle, false);
   2507     }
   2508 
   2509     /**
   2510      * Request that a rectangle of this view be visible on the screen,
   2511      * scrolling if necessary just enough.
   2512      *
   2513      * <p>A View should call this if it maintains some notion of which part
   2514      * of its content is interesting.  For example, a text editing view
   2515      * should call this when its cursor moves.
   2516      *
   2517      * <p>When <code>immediate</code> is set to true, scrolling will not be
   2518      * animated.
   2519      *
   2520      * @param rectangle The rectangle.
   2521      * @param immediate True to forbid animated scrolling, false otherwise
   2522      * @return Whether any parent scrolled.
   2523      */
   2524     public boolean requestRectangleOnScreen(Rect rectangle, boolean immediate) {
   2525         View child = this;
   2526         ViewParent parent = mParent;
   2527         boolean scrolled = false;
   2528         while (parent != null) {
   2529             scrolled |= parent.requestChildRectangleOnScreen(child,
   2530                     rectangle, immediate);
   2531 
   2532             // offset rect so next call has the rectangle in the
   2533             // coordinate system of its direct child.
   2534             rectangle.offset(child.getLeft(), child.getTop());
   2535             rectangle.offset(-child.getScrollX(), -child.getScrollY());
   2536 
   2537             if (!(parent instanceof View)) {
   2538                 break;
   2539             }
   2540 
   2541             child = (View) parent;
   2542             parent = child.getParent();
   2543         }
   2544         return scrolled;
   2545     }
   2546 
   2547     /**
   2548      * Called when this view wants to give up focus. This will cause
   2549      * {@link #onFocusChanged} to be called.
   2550      */
   2551     public void clearFocus() {
   2552         if (DBG) {
   2553             System.out.println(this + " clearFocus()");
   2554         }
   2555 
   2556         if ((mPrivateFlags & FOCUSED) != 0) {
   2557             mPrivateFlags &= ~FOCUSED;
   2558 
   2559             if (mParent != null) {
   2560                 mParent.clearChildFocus(this);
   2561             }
   2562 
   2563             onFocusChanged(false, 0, null);
   2564             refreshDrawableState();
   2565         }
   2566     }
   2567 
   2568     /**
   2569      * Called to clear the focus of a view that is about to be removed.
   2570      * Doesn't call clearChildFocus, which prevents this view from taking
   2571      * focus again before it has been removed from the parent
   2572      */
   2573     void clearFocusForRemoval() {
   2574         if ((mPrivateFlags & FOCUSED) != 0) {
   2575             mPrivateFlags &= ~FOCUSED;
   2576 
   2577             onFocusChanged(false, 0, null);
   2578             refreshDrawableState();
   2579         }
   2580     }
   2581 
   2582     /**
   2583      * Called internally by the view system when a new view is getting focus.
   2584      * This is what clears the old focus.
   2585      */
   2586     void unFocus() {
   2587         if (DBG) {
   2588             System.out.println(this + " unFocus()");
   2589         }
   2590 
   2591         if ((mPrivateFlags & FOCUSED) != 0) {
   2592             mPrivateFlags &= ~FOCUSED;
   2593 
   2594             onFocusChanged(false, 0, null);
   2595             refreshDrawableState();
   2596         }
   2597     }
   2598 
   2599     /**
   2600      * Returns true if this view has focus iteself, or is the ancestor of the
   2601      * view that has focus.
   2602      *
   2603      * @return True if this view has or contains focus, false otherwise.
   2604      */
   2605     @ViewDebug.ExportedProperty
   2606     public boolean hasFocus() {
   2607         return (mPrivateFlags & FOCUSED) != 0;
   2608     }
   2609 
   2610     /**
   2611      * Returns true if this view is focusable or if it contains a reachable View
   2612      * for which {@link #hasFocusable()} returns true. A "reachable hasFocusable()"
   2613      * is a View whose parents do not block descendants focus.
   2614      *
   2615      * Only {@link #VISIBLE} views are considered focusable.
   2616      *
   2617      * @return True if the view is focusable or if the view contains a focusable
   2618      *         View, false otherwise.
   2619      *
   2620      * @see ViewGroup#FOCUS_BLOCK_DESCENDANTS
   2621      */
   2622     public boolean hasFocusable() {
   2623         return (mViewFlags & VISIBILITY_MASK) == VISIBLE && isFocusable();
   2624     }
   2625 
   2626     /**
   2627      * Called by the view system when the focus state of this view changes.
   2628      * When the focus change event is caused by directional navigation, direction
   2629      * and previouslyFocusedRect provide insight into where the focus is coming from.
   2630      * When overriding, be sure to call up through to the super class so that
   2631      * the standard focus handling will occur.
   2632      *
   2633      * @param gainFocus True if the View has focus; false otherwise.
   2634      * @param direction The direction focus has moved when requestFocus()
   2635      *                  is called to give this view focus. Values are
   2636      *                  {@link #FOCUS_UP}, {@link #FOCUS_DOWN}, {@link #FOCUS_LEFT} or
   2637      *                  {@link #FOCUS_RIGHT}. It may not always apply, in which
   2638      *                  case use the default.
   2639      * @param previouslyFocusedRect The rectangle, in this view's coordinate
   2640      *        system, of the previously focused view.  If applicable, this will be
   2641      *        passed in as finer grained information about where the focus is coming
   2642      *        from (in addition to direction).  Will be <code>null</code> otherwise.
   2643      */
   2644     protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
   2645         if (gainFocus) {
   2646             sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
   2647         }
   2648 
   2649         InputMethodManager imm = InputMethodManager.peekInstance();
   2650         if (!gainFocus) {
   2651             if (isPressed()) {
   2652                 setPressed(false);
   2653             }
   2654             if (imm != null && mAttachInfo != null
   2655                     && mAttachInfo.mHasWindowFocus) {
   2656                 imm.focusOut(this);
   2657             }
   2658             onFocusLost();
   2659         } else if (imm != null && mAttachInfo != null
   2660                 && mAttachInfo.mHasWindowFocus) {
   2661             imm.focusIn(this);
   2662         }
   2663 
   2664         invalidate();
   2665         if (mOnFocusChangeListener != null) {
   2666             mOnFocusChangeListener.onFocusChange(this, gainFocus);
   2667         }
   2668 
   2669         if (mAttachInfo != null) {
   2670             mAttachInfo.mKeyDispatchState.reset(this);
   2671         }
   2672     }
   2673 
   2674     /**
   2675      * {@inheritDoc}
   2676      */
   2677     public void sendAccessibilityEvent(int eventType) {
   2678         if (AccessibilityManager.getInstance(mContext).isEnabled()) {
   2679             sendAccessibilityEventUnchecked(AccessibilityEvent.obtain(eventType));
   2680         }
   2681     }
   2682 
   2683     /**
   2684      * {@inheritDoc}
   2685      */
   2686     public void sendAccessibilityEventUnchecked(AccessibilityEvent event) {
   2687         event.setClassName(getClass().getName());
   2688         event.setPackageName(getContext().getPackageName());
   2689         event.setEnabled(isEnabled());
   2690         event.setContentDescription(mContentDescription);
   2691 
   2692         if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_FOCUSED && mAttachInfo != null) {
   2693             ArrayList<View> focusablesTempList = mAttachInfo.mFocusablesTempList;
   2694             getRootView().addFocusables(focusablesTempList, View.FOCUS_FORWARD, FOCUSABLES_ALL);
   2695             event.setItemCount(focusablesTempList.size());
   2696             event.setCurrentItemIndex(focusablesTempList.indexOf(this));
   2697             focusablesTempList.clear();
   2698         }
   2699 
   2700         dispatchPopulateAccessibilityEvent(event);
   2701 
   2702         AccessibilityManager.getInstance(mContext).sendAccessibilityEvent(event);
   2703     }
   2704 
   2705     /**
   2706      * Dispatches an {@link AccessibilityEvent} to the {@link View} children
   2707      * to be populated.
   2708      *
   2709      * @param event The event.
   2710      *
   2711      * @return True if the event population was completed.
   2712      */
   2713     public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
   2714         return false;
   2715     }
   2716 
   2717     /**
   2718      * Gets the {@link View} description. It briefly describes the view and is
   2719      * primarily used for accessibility support. Set this property to enable
   2720      * better accessibility support for your application. This is especially
   2721      * true for views that do not have textual representation (For example,
   2722      * ImageButton).
   2723      *
   2724      * @return The content descriptiopn.
   2725      *
   2726      * @attr ref android.R.styleable#View_contentDescription
   2727      */
   2728     public CharSequence getContentDescription() {
   2729         return mContentDescription;
   2730     }
   2731 
   2732     /**
   2733      * Sets the {@link View} description. It briefly describes the view and is
   2734      * primarily used for accessibility support. Set this property to enable
   2735      * better accessibility support for your application. This is especially
   2736      * true for views that do not have textual representation (For example,
   2737      * ImageButton).
   2738      *
   2739      * @param contentDescription The content description.
   2740      *
   2741      * @attr ref android.R.styleable#View_contentDescription
   2742      */
   2743     public void setContentDescription(CharSequence contentDescription) {
   2744         mContentDescription = contentDescription;
   2745     }
   2746 
   2747     /**
   2748      * Invoked whenever this view loses focus, either by losing window focus or by losing
   2749      * focus within its window. This method can be used to clear any state tied to the
   2750      * focus. For instance, if a button is held pressed with the trackball and the window
   2751      * loses focus, this method can be used to cancel the press.
   2752      *
   2753      * Subclasses of View overriding this method should always call super.onFocusLost().
   2754      *
   2755      * @see #onFocusChanged(boolean, int, android.graphics.Rect)
   2756      * @see #onWindowFocusChanged(boolean)
   2757      *
   2758      * @hide pending API council approval
   2759      */
   2760     protected void onFocusLost() {
   2761         resetPressedState();
   2762     }
   2763 
   2764     private void resetPressedState() {
   2765         if ((mViewFlags & ENABLED_MASK) == DISABLED) {
   2766             return;
   2767         }
   2768 
   2769         if (isPressed()) {
   2770             setPressed(false);
   2771 
   2772             if (!mHasPerformedLongPress) {
   2773                 removeLongPressCallback();
   2774             }
   2775         }
   2776     }
   2777 
   2778     /**
   2779      * Returns true if this view has focus
   2780      *
   2781      * @return True if this view has focus, false otherwise.
   2782      */
   2783     @ViewDebug.ExportedProperty
   2784     public boolean isFocused() {
   2785         return (mPrivateFlags & FOCUSED) != 0;
   2786     }
   2787 
   2788     /**
   2789      * Find the view in the hierarchy rooted at this view that currently has
   2790      * focus.
   2791      *
   2792      * @return The view that currently has focus, or null if no focused view can
   2793      *         be found.
   2794      */
   2795     public View findFocus() {
   2796         return (mPrivateFlags & FOCUSED) != 0 ? this : null;
   2797     }
   2798 
   2799     /**
   2800      * Change whether this view is one of the set of scrollable containers in
   2801      * its window.  This will be used to determine whether the window can
   2802      * resize or must pan when a soft input area is open -- scrollable
   2803      * containers allow the window to use resize mode since the container
   2804      * will appropriately shrink.
   2805      */
   2806     public void setScrollContainer(boolean isScrollContainer) {
   2807         if (isScrollContainer) {
   2808             if (mAttachInfo != null && (mPrivateFlags&SCROLL_CONTAINER_ADDED) == 0) {
   2809                 mAttachInfo.mScrollContainers.add(this);
   2810                 mPrivateFlags |= SCROLL_CONTAINER_ADDED;
   2811             }
   2812             mPrivateFlags |= SCROLL_CONTAINER;
   2813         } else {
   2814             if ((mPrivateFlags&SCROLL_CONTAINER_ADDED) != 0) {
   2815                 mAttachInfo.mScrollContainers.remove(this);
   2816             }
   2817             mPrivateFlags &= ~(SCROLL_CONTAINER|SCROLL_CONTAINER_ADDED);
   2818         }
   2819     }
   2820 
   2821     /**
   2822      * Returns the quality of the drawing cache.
   2823      *
   2824      * @return One of {@link #DRAWING_CACHE_QUALITY_AUTO},
   2825      *         {@link #DRAWING_CACHE_QUALITY_LOW}, or {@link #DRAWING_CACHE_QUALITY_HIGH}
   2826      *
   2827      * @see #setDrawingCacheQuality(int)
   2828      * @see #setDrawingCacheEnabled(boolean)
   2829      * @see #isDrawingCacheEnabled()
   2830      *
   2831      * @attr ref android.R.styleable#View_drawingCacheQuality
   2832      */
   2833     public int getDrawingCacheQuality() {
   2834         return mViewFlags & DRAWING_CACHE_QUALITY_MASK;
   2835     }
   2836 
   2837     /**
   2838      * Set the drawing cache quality of this view. This value is used only when the
   2839      * drawing cache is enabled
   2840      *
   2841      * @param quality One of {@link #DRAWING_CACHE_QUALITY_AUTO},
   2842      *        {@link #DRAWING_CACHE_QUALITY_LOW}, or {@link #DRAWING_CACHE_QUALITY_HIGH}
   2843      *
   2844      * @see #getDrawingCacheQuality()
   2845      * @see #setDrawingCacheEnabled(boolean)
   2846      * @see #isDrawingCacheEnabled()
   2847      *
   2848      * @attr ref android.R.styleable#View_drawingCacheQuality
   2849      */
   2850     public void setDrawingCacheQuality(int quality) {
   2851         setFlags(quality, DRAWING_CACHE_QUALITY_MASK);
   2852     }
   2853 
   2854     /**
   2855      * Returns whether the screen should remain on, corresponding to the current
   2856      * value of {@link #KEEP_SCREEN_ON}.
   2857      *
   2858      * @return Returns true if {@link #KEEP_SCREEN_ON} is set.
   2859      *
   2860      * @see #setKeepScreenOn(boolean)
   2861      *
   2862      * @attr ref android.R.styleable#View_keepScreenOn
   2863      */
   2864     public boolean getKeepScreenOn() {
   2865         return (mViewFlags & KEEP_SCREEN_ON) != 0;
   2866     }
   2867 
   2868     /**
   2869      * Controls whether the screen should remain on, modifying the
   2870      * value of {@link #KEEP_SCREEN_ON}.
   2871      *
   2872      * @param keepScreenOn Supply true to set {@link #KEEP_SCREEN_ON}.
   2873      *
   2874      * @see #getKeepScreenOn()
   2875      *
   2876      * @attr ref android.R.styleable#View_keepScreenOn
   2877      */
   2878     public void setKeepScreenOn(boolean keepScreenOn) {
   2879         setFlags(keepScreenOn ? KEEP_SCREEN_ON : 0, KEEP_SCREEN_ON);
   2880     }
   2881 
   2882     /**
   2883      * @return The user specified next focus ID.
   2884      *
   2885      * @attr ref android.R.styleable#View_nextFocusLeft
   2886      */
   2887     public int getNextFocusLeftId() {
   2888         return mNextFocusLeftId;
   2889     }
   2890 
   2891     /**
   2892      * Set the id of the view to use for the next focus
   2893      *
   2894      * @param nextFocusLeftId
   2895      *
   2896      * @attr ref android.R.styleable#View_nextFocusLeft
   2897      */
   2898     public void setNextFocusLeftId(int nextFocusLeftId) {
   2899         mNextFocusLeftId = nextFocusLeftId;
   2900     }
   2901 
   2902     /**
   2903      * @return The user specified next focus ID.
   2904      *
   2905      * @attr ref android.R.styleable#View_nextFocusRight
   2906      */
   2907     public int getNextFocusRightId() {
   2908         return mNextFocusRightId;
   2909     }
   2910 
   2911     /**
   2912      * Set the id of the view to use for the next focus
   2913      *
   2914      * @param nextFocusRightId
   2915      *
   2916      * @attr ref android.R.styleable#View_nextFocusRight
   2917      */
   2918     public void setNextFocusRightId(int nextFocusRightId) {
   2919         mNextFocusRightId = nextFocusRightId;
   2920     }
   2921 
   2922     /**
   2923      * @return The user specified next focus ID.
   2924      *
   2925      * @attr ref android.R.styleable#View_nextFocusUp
   2926      */
   2927     public int getNextFocusUpId() {
   2928         return mNextFocusUpId;
   2929     }
   2930 
   2931     /**
   2932      * Set the id of the view to use for the next focus
   2933      *
   2934      * @param nextFocusUpId
   2935      *
   2936      * @attr ref android.R.styleable#View_nextFocusUp
   2937      */
   2938     public void setNextFocusUpId(int nextFocusUpId) {
   2939         mNextFocusUpId = nextFocusUpId;
   2940     }
   2941 
   2942     /**
   2943      * @return The user specified next focus ID.
   2944      *
   2945      * @attr ref android.R.styleable#View_nextFocusDown
   2946      */
   2947     public int getNextFocusDownId() {
   2948         return mNextFocusDownId;
   2949     }
   2950 
   2951     /**
   2952      * Set the id of the view to use for the next focus
   2953      *
   2954      * @param nextFocusDownId
   2955      *
   2956      * @attr ref android.R.styleable#View_nextFocusDown
   2957      */
   2958     public void setNextFocusDownId(int nextFocusDownId) {
   2959         mNextFocusDownId = nextFocusDownId;
   2960     }
   2961 
   2962     /**
   2963      * Returns the visibility of this view and all of its ancestors
   2964      *
   2965      * @return True if this view and all of its ancestors are {@link #VISIBLE}
   2966      */
   2967     public boolean isShown() {
   2968         View current = this;
   2969         //noinspection ConstantConditions
   2970         do {
   2971             if ((current.mViewFlags & VISIBILITY_MASK) != VISIBLE) {
   2972                 return false;
   2973             }
   2974             ViewParent parent = current.mParent;
   2975             if (parent == null) {
   2976                 return false; // We are not attached to the view root
   2977             }
   2978             if (!(parent instanceof View)) {
   2979                 return true;
   2980             }
   2981             current = (View) parent;
   2982         } while (current != null);
   2983 
   2984         return false;
   2985     }
   2986 
   2987     /**
   2988      * Apply the insets for system windows to this view, if the FITS_SYSTEM_WINDOWS flag
   2989      * is set
   2990      *
   2991      * @param insets Insets for system windows
   2992      *
   2993      * @return True if this view applied the insets, false otherwise
   2994      */
   2995     protected boolean fitSystemWindows(Rect insets) {
   2996         if ((mViewFlags & FITS_SYSTEM_WINDOWS) == FITS_SYSTEM_WINDOWS) {
   2997             mPaddingLeft = insets.left;
   2998             mPaddingTop = insets.top;
   2999             mPaddingRight = insets.right;
   3000             mPaddingBottom = insets.bottom;
   3001             requestLayout();
   3002             return true;
   3003         }
   3004         return false;
   3005     }
   3006 
   3007     /**
   3008      * Returns the visibility status for this view.
   3009      *
   3010      * @return One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
   3011      * @attr ref android.R.styleable#View_visibility
   3012      */
   3013     @ViewDebug.ExportedProperty(mapping = {
   3014         @ViewDebug.IntToString(from = VISIBLE,   to = "VISIBLE"),
   3015         @ViewDebug.IntToString(from = INVISIBLE, to = "INVISIBLE"),
   3016         @ViewDebug.IntToString(from = GONE,      to = "GONE")
   3017     })
   3018     public int getVisibility() {
   3019         return mViewFlags & VISIBILITY_MASK;
   3020     }
   3021 
   3022     /**
   3023      * Set the enabled state of this view.
   3024      *
   3025      * @param visibility One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
   3026      * @attr ref android.R.styleable#View_visibility
   3027      */
   3028     @RemotableViewMethod
   3029     public void setVisibility(int visibility) {
   3030         setFlags(visibility, VISIBILITY_MASK);
   3031         if (mBGDrawable != null) mBGDrawable.setVisible(visibility == VISIBLE, false);
   3032     }
   3033 
   3034     /**
   3035      * Returns the enabled status for this view. The interpretation of the
   3036      * enabled state varies by subclass.
   3037      *
   3038      * @return True if this view is enabled, false otherwise.
   3039      */
   3040     @ViewDebug.ExportedProperty
   3041     public boolean isEnabled() {
   3042         return (mViewFlags & ENABLED_MASK) == ENABLED;
   3043     }
   3044 
   3045     /**
   3046      * Set the enabled state of this view. The interpretation of the enabled
   3047      * state varies by subclass.
   3048      *
   3049      * @param enabled True if this view is enabled, false otherwise.
   3050      */
   3051     @RemotableViewMethod
   3052     public void setEnabled(boolean enabled) {
   3053         if (enabled == isEnabled()) return;
   3054 
   3055         setFlags(enabled ? ENABLED : DISABLED, ENABLED_MASK);
   3056 
   3057         /*
   3058          * The View most likely has to change its appearance, so refresh
   3059          * the drawable state.
   3060          */
   3061         refreshDrawableState();
   3062 
   3063         // Invalidate too, since the default behavior for views is to be
   3064         // be drawn at 50% alpha rather than to change the drawable.
   3065         invalidate();
   3066     }
   3067 
   3068     /**
   3069      * Set whether this view can receive the focus.
   3070      *
   3071      * Setting this to false will also ensure that this view is not focusable
   3072      * in touch mode.
   3073      *
   3074      * @param focusable If true, this view can receive the focus.
   3075      *
   3076      * @see #setFocusableInTouchMode(boolean)
   3077      * @attr ref android.R.styleable#View_focusable
   3078      */
   3079     public void setFocusable(boolean focusable) {
   3080         if (!focusable) {
   3081             setFlags(0, FOCUSABLE_IN_TOUCH_MODE);
   3082         }
   3083         setFlags(focusable ? FOCUSABLE : NOT_FOCUSABLE, FOCUSABLE_MASK);
   3084     }
   3085 
   3086     /**
   3087      * Set whether this view can receive focus while in touch mode.
   3088      *
   3089      * Setting this to true will also ensure that this view is focusable.
   3090      *
   3091      * @param focusableInTouchMode If true, this view can receive the focus while
   3092      *   in touch mode.
   3093      *
   3094      * @see #setFocusable(boolean)
   3095      * @attr ref android.R.styleable#View_focusableInTouchMode
   3096      */
   3097     public void setFocusableInTouchMode(boolean focusableInTouchMode) {
   3098         // Focusable in touch mode should always be set before the focusable flag
   3099         // otherwise, setting the focusable flag will trigger a focusableViewAvailable()
   3100         // which, in touch mode, will not successfully request focus on this view
   3101         // because the focusable in touch mode flag is not set
   3102         setFlags(focusableInTouchMode ? FOCUSABLE_IN_TOUCH_MODE : 0, FOCUSABLE_IN_TOUCH_MODE);
   3103         if (focusableInTouchMode) {
   3104             setFlags(FOCUSABLE, FOCUSABLE_MASK);
   3105         }
   3106     }
   3107 
   3108     /**
   3109      * Set whether this view should have sound effects enabled for events such as
   3110      * clicking and touching.
   3111      *
   3112      * <p>You may wish to disable sound effects for a view if you already play sounds,
   3113      * for instance, a dial key that plays dtmf tones.
   3114      *
   3115      * @param soundEffectsEnabled whether sound effects are enabled for this view.
   3116      * @see #isSoundEffectsEnabled()
   3117      * @see #playSoundEffect(int)
   3118      * @attr ref android.R.styleable#View_soundEffectsEnabled
   3119      */
   3120     public void setSoundEffectsEnabled(boolean soundEffectsEnabled) {
   3121         setFlags(soundEffectsEnabled ? SOUND_EFFECTS_ENABLED: 0, SOUND_EFFECTS_ENABLED);
   3122     }
   3123 
   3124     /**
   3125      * @return whether this view should have sound effects enabled for events such as
   3126      *     clicking and touching.
   3127      *
   3128      * @see #setSoundEffectsEnabled(boolean)
   3129      * @see #playSoundEffect(int)
   3130      * @attr ref android.R.styleable#View_soundEffectsEnabled
   3131      */
   3132     @ViewDebug.ExportedProperty
   3133     public boolean isSoundEffectsEnabled() {
   3134         return SOUND_EFFECTS_ENABLED == (mViewFlags & SOUND_EFFECTS_ENABLED);
   3135     }
   3136 
   3137     /**
   3138      * Set whether this view should have haptic feedback for events such as
   3139      * long presses.
   3140      *
   3141      * <p>You may wish to disable haptic feedback if your view already controls
   3142      * its own haptic feedback.
   3143      *
   3144      * @param hapticFeedbackEnabled whether haptic feedback enabled for this view.
   3145      * @see #isHapticFeedbackEnabled()
   3146      * @see #performHapticFeedback(int)
   3147      * @attr ref android.R.styleable#View_hapticFeedbackEnabled
   3148      */
   3149     public void setHapticFeedbackEnabled(boolean hapticFeedbackEnabled) {
   3150         setFlags(hapticFeedbackEnabled ? HAPTIC_FEEDBACK_ENABLED: 0, HAPTIC_FEEDBACK_ENABLED);
   3151     }
   3152 
   3153     /**
   3154      * @return whether this view should have haptic feedback enabled for events
   3155      * long presses.
   3156      *
   3157      * @see #setHapticFeedbackEnabled(boolean)
   3158      * @see #performHapticFeedback(int)
   3159      * @attr ref android.R.styleable#View_hapticFeedbackEnabled
   3160      */
   3161     @ViewDebug.ExportedProperty
   3162     public boolean isHapticFeedbackEnabled() {
   3163         return HAPTIC_FEEDBACK_ENABLED == (mViewFlags & HAPTIC_FEEDBACK_ENABLED);
   3164     }
   3165 
   3166     /**
   3167      * If this view doesn't do any drawing on its own, set this flag to
   3168      * allow further optimizations. By default, this flag is not set on
   3169      * View, but could be set on some View subclasses such as ViewGroup.
   3170      *
   3171      * Typically, if you override {@link #onDraw} you should clear this flag.
   3172      *
   3173      * @param willNotDraw whether or not this View draw on its own
   3174      */
   3175     public void setWillNotDraw(boolean willNotDraw) {
   3176         setFlags(willNotDraw ? WILL_NOT_DRAW : 0, DRAW_MASK);
   3177     }
   3178 
   3179     /**
   3180      * Returns whether or not this View draws on its own.
   3181      *
   3182      * @return true if this view has nothing to draw, false otherwise
   3183      */
   3184     @ViewDebug.ExportedProperty
   3185     public boolean willNotDraw() {
   3186         return (mViewFlags & DRAW_MASK) == WILL_NOT_DRAW;
   3187     }
   3188 
   3189     /**
   3190      * When a View's drawing cache is enabled, drawing is redirected to an
   3191      * offscreen bitmap. Some views, like an ImageView, must be able to
   3192      * bypass this mechanism if they already draw a single bitmap, to avoid
   3193      * unnecessary usage of the memory.
   3194      *
   3195      * @param willNotCacheDrawing true if this view does not cache its
   3196      *        drawing, false otherwise
   3197      */
   3198     public void setWillNotCacheDrawing(boolean willNotCacheDrawing) {
   3199         setFlags(willNotCacheDrawing ? WILL_NOT_CACHE_DRAWING : 0, WILL_NOT_CACHE_DRAWING);
   3200     }
   3201 
   3202     /**
   3203      * Returns whether or not this View can cache its drawing or not.
   3204      *
   3205      * @return true if this view does not cache its drawing, false otherwise
   3206      */
   3207     @ViewDebug.ExportedProperty
   3208     public boolean willNotCacheDrawing() {
   3209         return (mViewFlags & WILL_NOT_CACHE_DRAWING) == WILL_NOT_CACHE_DRAWING;
   3210     }
   3211 
   3212     /**
   3213      * Indicates whether this view reacts to click events or not.
   3214      *
   3215      * @return true if the view is clickable, false otherwise
   3216      *
   3217      * @see #setClickable(boolean)
   3218      * @attr ref android.R.styleable#View_clickable
   3219      */
   3220     @ViewDebug.ExportedProperty
   3221     public boolean isClickable() {
   3222         return (mViewFlags & CLICKABLE) == CLICKABLE;
   3223     }
   3224 
   3225     /**
   3226      * Enables or disables click events for this view. When a view
   3227      * is clickable it will change its state to "pressed" on every click.
   3228      * Subclasses should set the view clickable to visually react to
   3229      * user's clicks.
   3230      *
   3231      * @param clickable true to make the view clickable, false otherwise
   3232      *
   3233      * @see #isClickable()
   3234      * @attr ref android.R.styleable#View_clickable
   3235      */
   3236     public void setClickable(boolean clickable) {
   3237         setFlags(clickable ? CLICKABLE : 0, CLICKABLE);
   3238     }
   3239 
   3240     /**
   3241      * Indicates whether this view reacts to long click events or not.
   3242      *
   3243      * @return true if the view is long clickable, false otherwise
   3244      *
   3245      * @see #setLongClickable(boolean)
   3246      * @attr ref android.R.styleable#View_longClickable
   3247      */
   3248     public boolean isLongClickable() {
   3249         return (mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE;
   3250     }
   3251 
   3252     /**
   3253      * Enables or disables long click events for this view. When a view is long
   3254      * clickable it reacts to the user holding down the button for a longer
   3255      * duration than a tap. This event can either launch the listener or a
   3256      * context menu.
   3257      *
   3258      * @param longClickable true to make the view long clickable, false otherwise
   3259      * @see #isLongClickable()
   3260      * @attr ref android.R.styleable#View_longClickable
   3261      */
   3262     public void setLongClickable(boolean longClickable) {
   3263         setFlags(longClickable ? LONG_CLICKABLE : 0, LONG_CLICKABLE);
   3264     }
   3265 
   3266     /**
   3267      * Sets the pressed that for this view.
   3268      *
   3269      * @see #isClickable()
   3270      * @see #setClickable(boolean)
   3271      *
   3272      * @param pressed Pass true to set the View's internal state to "pressed", or false to reverts
   3273      *        the View's internal state from a previously set "pressed" state.
   3274      */
   3275     public void setPressed(boolean pressed) {
   3276         if (pressed) {
   3277             mPrivateFlags |= PRESSED;
   3278         } else {
   3279             mPrivateFlags &= ~PRESSED;
   3280         }
   3281         refreshDrawableState();
   3282         dispatchSetPressed(pressed);
   3283     }
   3284 
   3285     /**
   3286      * Dispatch setPressed to all of this View's children.
   3287      *
   3288      * @see #setPressed(boolean)
   3289      *
   3290      * @param pressed The new pressed state
   3291      */
   3292     protected void dispatchSetPressed(boolean pressed) {
   3293     }
   3294 
   3295     /**
   3296      * Indicates whether the view is currently in pressed state. Unless
   3297      * {@link #setPressed(boolean)} is explicitly called, only clickable views can enter
   3298      * the pressed state.
   3299      *
   3300      * @see #setPressed
   3301      * @see #isClickable()
   3302      * @see #setClickable(boolean)
   3303      *
   3304      * @return true if the view is currently pressed, false otherwise
   3305      */
   3306     public boolean isPressed() {
   3307         return (mPrivateFlags & PRESSED) == PRESSED;
   3308     }
   3309 
   3310     /**
   3311      * Indicates whether this view will save its state (that is,
   3312      * whether its {@link #onSaveInstanceState} method will be called).
   3313      *
   3314      * @return Returns true if the view state saving is enabled, else false.
   3315      *
   3316      * @see #setSaveEnabled(boolean)
   3317      * @attr ref android.R.styleable#View_saveEnabled
   3318      */
   3319     public boolean isSaveEnabled() {
   3320         return (mViewFlags & SAVE_DISABLED_MASK) != SAVE_DISABLED;
   3321     }
   3322 
   3323     /**
   3324      * Controls whether the saving of this view's state is
   3325      * enabled (that is, whether its {@link #onSaveInstanceState} method
   3326      * will be called).  Note that even if freezing is enabled, the
   3327      * view still must have an id assigned to it (via {@link #setId setId()})
   3328      * for its state to be saved.  This flag can only disable the
   3329      * saving of this view; any child views may still have their state saved.
   3330      *
   3331      * @param enabled Set to false to <em>disable</em> state saving, or true
   3332      * (the default) to allow it.
   3333      *
   3334      * @see #isSaveEnabled()
   3335      * @see #setId(int)
   3336      * @see #onSaveInstanceState()
   3337      * @attr ref android.R.styleable#View_saveEnabled
   3338      */
   3339     public void setSaveEnabled(boolean enabled) {
   3340         setFlags(enabled ? 0 : SAVE_DISABLED, SAVE_DISABLED_MASK);
   3341     }
   3342 
   3343 
   3344     /**
   3345      * Returns whether this View is able to take focus.
   3346      *
   3347      * @return True if this view can take focus, or false otherwise.
   3348      * @attr ref android.R.styleable#View_focusable
   3349      */
   3350     @ViewDebug.ExportedProperty
   3351     public final boolean isFocusable() {
   3352         return FOCUSABLE == (mViewFlags & FOCUSABLE_MASK);
   3353     }
   3354 
   3355     /**
   3356      * When a view is focusable, it may not want to take focus when in touch mode.
   3357      * For example, a button would like focus when the user is navigating via a D-pad
   3358      * so that the user can click on it, but once the user starts touching the screen,
   3359      * the button shouldn't take focus
   3360      * @return Whether the view is focusable in touch mode.
   3361      * @attr ref android.R.styleable#View_focusableInTouchMode
   3362      */
   3363     @ViewDebug.ExportedProperty
   3364     public final boolean isFocusableInTouchMode() {
   3365         return FOCUSABLE_IN_TOUCH_MODE == (mViewFlags & FOCUSABLE_IN_TOUCH_MODE);
   3366     }
   3367 
   3368     /**
   3369      * Find the nearest view in the specified direction that can take focus.
   3370      * This does not actually give focus to that view.
   3371      *
   3372      * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
   3373      *
   3374      * @return The nearest focusable in the specified direction, or null if none
   3375      *         can be found.
   3376      */
   3377     public View focusSearch(int direction) {
   3378         if (mParent != null) {
   3379             return mParent.focusSearch(this, direction);
   3380         } else {
   3381             return null;
   3382         }
   3383     }
   3384 
   3385     /**
   3386      * This method is the last chance for the focused view and its ancestors to
   3387      * respond to an arrow key. This is called when the focused view did not
   3388      * consume the key internally, nor could the view system find a new view in
   3389      * the requested direction to give focus to.
   3390      *
   3391      * @param focused The currently focused view.
   3392      * @param direction The direction focus wants to move. One of FOCUS_UP,
   3393      *        FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT.
   3394      * @return True if the this view consumed this unhandled move.
   3395      */
   3396     public boolean dispatchUnhandledMove(View focused, int direction) {
   3397         return false;
   3398     }
   3399 
   3400     /**
   3401      * If a user manually specified the next view id for a particular direction,
   3402      * use the root to look up the view.  Once a view is found, it is cached
   3403      * for future lookups.
   3404      * @param root The root view of the hierarchy containing this view.
   3405      * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
   3406      * @return The user specified next view, or null if there is none.
   3407      */
   3408     View findUserSetNextFocus(View root, int direction) {
   3409         switch (direction) {
   3410             case FOCUS_LEFT:
   3411                 if (mNextFocusLeftId == View.NO_ID) return null;
   3412                 return findViewShouldExist(root, mNextFocusLeftId);
   3413             case FOCUS_RIGHT:
   3414                 if (mNextFocusRightId == View.NO_ID) return null;
   3415                 return findViewShouldExist(root, mNextFocusRightId);
   3416             case FOCUS_UP:
   3417                 if (mNextFocusUpId == View.NO_ID) return null;
   3418                 return findViewShouldExist(root, mNextFocusUpId);
   3419             case FOCUS_DOWN:
   3420                 if (mNextFocusDownId == View.NO_ID) return null;
   3421                 return findViewShouldExist(root, mNextFocusDownId);
   3422         }
   3423         return null;
   3424     }
   3425 
   3426     private static View findViewShouldExist(View root, int childViewId) {
   3427         View result = root.findViewById(childViewId);
   3428         if (result == null) {
   3429             Log.w(VIEW_LOG_TAG, "couldn't find next focus view specified "
   3430                     + "by user for id " + childViewId);
   3431         }
   3432         return result;
   3433     }
   3434 
   3435     /**
   3436      * Find and return all focusable views that are descendants of this view,
   3437      * possibly including this view if it is focusable itself.
   3438      *
   3439      * @param direction The direction of the focus
   3440      * @return A list of focusable views
   3441      */
   3442     public ArrayList<View> getFocusables(int direction) {
   3443         ArrayList<View> result = new ArrayList<View>(24);
   3444         addFocusables(result, direction);
   3445         return result;
   3446     }
   3447 
   3448     /**
   3449      * Add any focusable views that are descendants of this view (possibly
   3450      * including this view if it is focusable itself) to views.  If we are in touch mode,
   3451      * only add views that are also focusable in touch mode.
   3452      *
   3453      * @param views Focusable views found so far
   3454      * @param direction The direction of the focus
   3455      */
   3456     public void addFocusables(ArrayList<View> views, int direction) {
   3457         addFocusables(views, direction, FOCUSABLES_TOUCH_MODE);
   3458     }
   3459 
   3460     /**
   3461      * Adds any focusable views that are descendants of this view (possibly
   3462      * including this view if it is focusable itself) to views. This method
   3463      * adds all focusable views regardless if we are in touch mode or
   3464      * only views focusable in touch mode if we are in touch mode depending on
   3465      * the focusable mode paramater.
   3466      *
   3467      * @param views Focusable views found so far or null if all we are interested is
   3468      *        the number of focusables.
   3469      * @param direction The direction of the focus.
   3470      * @param focusableMode The type of focusables to be added.
   3471      *
   3472      * @see #FOCUSABLES_ALL
   3473      * @see #FOCUSABLES_TOUCH_MODE
   3474      */
   3475     public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
   3476         if (!isFocusable()) {
   3477             return;
   3478         }
   3479 
   3480         if ((focusableMode & FOCUSABLES_TOUCH_MODE) == FOCUSABLES_TOUCH_MODE &&
   3481                 isInTouchMode() && !isFocusableInTouchMode()) {
   3482             return;
   3483         }
   3484 
   3485         if (views != null) {
   3486             views.add(this);
   3487         }
   3488     }
   3489 
   3490     /**
   3491      * Find and return all touchable views that are descendants of this view,
   3492      * possibly including this view if it is touchable itself.
   3493      *
   3494      * @return A list of touchable views
   3495      */
   3496     public ArrayList<View> getTouchables() {
   3497         ArrayList<View> result = new ArrayList<View>();
   3498         addTouchables(result);
   3499         return result;
   3500     }
   3501 
   3502     /**
   3503      * Add any touchable views that are descendants of this view (possibly
   3504      * including this view if it is touchable itself) to views.
   3505      *
   3506      * @param views Touchable views found so far
   3507      */
   3508     public void addTouchables(ArrayList<View> views) {
   3509         final int viewFlags = mViewFlags;
   3510 
   3511         if (((viewFlags & CLICKABLE) == CLICKABLE || (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)
   3512                 && (viewFlags & ENABLED_MASK) == ENABLED) {
   3513             views.add(this);
   3514         }
   3515     }
   3516 
   3517     /**
   3518      * Call this to try to give focus to a specific view or to one of its
   3519      * descendants.
   3520      *
   3521      * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns false),
   3522      * or if it is focusable and it is not focusable in touch mode ({@link #isFocusableInTouchMode})
   3523      * while the device is in touch mode.
   3524      *
   3525      * See also {@link #focusSearch}, which is what you call to say that you
   3526      * have focus, and you want your parent to look for the next one.
   3527      *
   3528      * This is equivalent to calling {@link #requestFocus(int, Rect)} with arguments
   3529      * {@link #FOCUS_DOWN} and <code>null</code>.
   3530      *
   3531      * @return Whether this view or one of its descendants actually took focus.
   3532      */
   3533     public final boolean requestFocus() {
   3534         return requestFocus(View.FOCUS_DOWN);
   3535     }
   3536 
   3537 
   3538     /**
   3539      * Call this to try to give focus to a specific view or to one of its
   3540      * descendants and give it a hint about what direction focus is heading.
   3541      *
   3542      * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns false),
   3543      * or if it is focusable and it is not focusable in touch mode ({@link #isFocusableInTouchMode})
   3544      * while the device is in touch mode.
   3545      *
   3546      * See also {@link #focusSearch}, which is what you call to say that you
   3547      * have focus, and you want your parent to look for the next one.
   3548      *
   3549      * This is equivalent to calling {@link #requestFocus(int, Rect)} with
   3550      * <code>null</code> set for the previously focused rectangle.
   3551      *
   3552      * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
   3553      * @return Whether this view or one of its descendants actually took focus.
   3554      */
   3555     public final boolean requestFocus(int direction) {
   3556         return requestFocus(direction, null);
   3557     }
   3558 
   3559     /**
   3560      * Call this to try to give focus to a specific view or to one of its descendants
   3561      * and give it hints about the direction and a specific rectangle that the focus
   3562      * is coming from.  The rectangle can help give larger views a finer grained hint
   3563      * about where focus is coming from, and therefore, where to show selection, or
   3564      * forward focus change internally.
   3565      *
   3566      * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns false),
   3567      * or if it is focusable and it is not focusable in touch mode ({@link #isFocusableInTouchMode})
   3568      * while the device is in touch mode.
   3569      *
   3570      * A View will not take focus if it is not visible.
   3571      *
   3572      * A View will not take focus if one of its parents has {@link android.view.ViewGroup#getDescendantFocusability()}
   3573      * equal to {@link ViewGroup#FOCUS_BLOCK_DESCENDANTS}.
   3574      *
   3575      * See also {@link #focusSearch}, which is what you call to say that you
   3576      * have focus, and you want your parent to look for the next one.
   3577      *
   3578      * You may wish to override this method if your custom {@link View} has an internal
   3579      * {@link View} that it wishes to forward the request to.
   3580      *
   3581      * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
   3582      * @param previouslyFocusedRect The rectangle (in this View's coordinate system)
   3583      *        to give a finer grained hint about where focus is coming from.  May be null
   3584      *        if there is no hint.
   3585      * @return Whether this view or one of its descendants actually took focus.
   3586      */
   3587     public boolean requestFocus(int direction, Rect previouslyFocusedRect) {
   3588         // need to be focusable
   3589         if ((mViewFlags & FOCUSABLE_MASK) != FOCUSABLE ||
   3590                 (mViewFlags & VISIBILITY_MASK) != VISIBLE) {
   3591             return false;
   3592         }
   3593 
   3594         // need to be focusable in touch mode if in touch mode
   3595         if (isInTouchMode() &&
   3596                 (FOCUSABLE_IN_TOUCH_MODE != (mViewFlags & FOCUSABLE_IN_TOUCH_MODE))) {
   3597             return false;
   3598         }
   3599 
   3600         // need to not have any parents blocking us
   3601         if (hasAncestorThatBlocksDescendantFocus()) {
   3602             return false;
   3603         }
   3604 
   3605         handleFocusGainInternal(direction, previouslyFocusedRect);
   3606         return true;
   3607     }
   3608 
   3609     /**
   3610      * Call this to try to give focus to a specific view or to one of its descendants. This is a
   3611      * special variant of {@link #requestFocus() } that will allow views that are not focuable in
   3612      * touch mode to request focus when they are touched.
   3613      *
   3614      * @return Whether this view or one of its descendants actually took focus.
   3615      *
   3616      * @see #isInTouchMode()
   3617      *
   3618      */
   3619     public final boolean requestFocusFromTouch() {
   3620         // Leave touch mode if we need to
   3621         if (isInTouchMode()) {
   3622             View root = getRootView();
   3623             if (root != null) {
   3624                ViewRoot viewRoot = (ViewRoot)root.getParent();
   3625                if (viewRoot != null) {
   3626                    viewRoot.ensureTouchMode(false);
   3627                }
   3628             }
   3629         }
   3630         return requestFocus(View.FOCUS_DOWN);
   3631     }
   3632 
   3633     /**
   3634      * @return Whether any ancestor of this view blocks descendant focus.
   3635      */
   3636     private boolean hasAncestorThatBlocksDescendantFocus() {
   3637         ViewParent ancestor = mParent;
   3638         while (ancestor instanceof ViewGroup) {
   3639             final ViewGroup vgAncestor = (ViewGroup) ancestor;
   3640             if (vgAncestor.getDescendantFocusability() == ViewGroup.FOCUS_BLOCK_DESCENDANTS) {
   3641                 return true;
   3642             } else {
   3643                 ancestor = vgAncestor.getParent();
   3644             }
   3645         }
   3646         return false;
   3647     }
   3648 
   3649     /**
   3650      * @hide
   3651      */
   3652     public void dispatchStartTemporaryDetach() {
   3653         onStartTemporaryDetach();
   3654     }
   3655 
   3656     /**
   3657      * This is called when a container is going to temporarily detach a child, with
   3658      * {@link ViewGroup#detachViewFromParent(View) ViewGroup.detachViewFromParent}.
   3659      * It will either be followed by {@link #onFinishTemporaryDetach()} or
   3660      * {@link #onDetachedFromWindow()} when the container is done.
   3661      */
   3662     public void onStartTemporaryDetach() {
   3663         removeUnsetPressCallback();
   3664         mPrivateFlags |= CANCEL_NEXT_UP_EVENT;
   3665     }
   3666 
   3667     /**
   3668      * @hide
   3669      */
   3670     public void dispatchFinishTemporaryDetach() {
   3671         onFinishTemporaryDetach();
   3672     }
   3673 
   3674     /**
   3675      * Called after {@link #onStartTemporaryDetach} when the container is done
   3676      * changing the view.
   3677      */
   3678     public void onFinishTemporaryDetach() {
   3679     }
   3680 
   3681     /**
   3682      * capture information of this view for later analysis: developement only
   3683      * check dynamic switch to make sure we only dump view
   3684      * when ViewDebug.SYSTEM_PROPERTY_CAPTURE_VIEW) is set
   3685      */
   3686     private static void captureViewInfo(String subTag, View v) {
   3687         if (v == null || SystemProperties.getInt(ViewDebug.SYSTEM_PROPERTY_CAPTURE_VIEW, 0) == 0) {
   3688             return;
   3689         }
   3690         ViewDebug.dumpCapturedView(subTag, v);
   3691     }
   3692 
   3693     /**
   3694      * Return the global {@link KeyEvent.DispatcherState KeyEvent.DispatcherState}
   3695      * for this view's window.  Returns null if the view is not currently attached
   3696      * to the window.  Normally you will not need to use this directly, but
   3697      * just use the standard high-level event callbacks like {@link #onKeyDown}.
   3698      */
   3699     public KeyEvent.DispatcherState getKeyDispatcherState() {
   3700         return mAttachInfo != null ? mAttachInfo.mKeyDispatchState : null;
   3701     }
   3702 
   3703     /**
   3704      * Dispatch a key event before it is processed by any input method
   3705      * associated with the view hierarchy.  This can be used to intercept
   3706      * key events in special situations before the IME consumes them; a
   3707      * typical example would be handling the BACK key to update the application's
   3708      * UI instead of allowing the IME to see it and close itself.
   3709      *
   3710      * @param event The key event to be dispatched.
   3711      * @return True if the event was handled, false otherwise.
   3712      */
   3713     public boolean dispatchKeyEventPreIme(KeyEvent event) {
   3714         return onKeyPreIme(event.getKeyCode(), event);
   3715     }
   3716 
   3717     /**
   3718      * Dispatch a key event to the next view on the focus path. This path runs
   3719      * from the top of the view tree down to the currently focused view. If this
   3720      * view has focus, it will dispatch to itself. Otherwise it will dispatch
   3721      * the next node down the focus path. This method also fires any key
   3722      * listeners.
   3723      *
   3724      * @param event The key event to be dispatched.
   3725      * @return True if the event was handled, false otherwise.
   3726      */
   3727     public boolean dispatchKeyEvent(KeyEvent event) {
   3728         // If any attached key listener a first crack at the event.
   3729         //noinspection SimplifiableIfStatement
   3730 
   3731         if (android.util.Config.LOGV) {
   3732             captureViewInfo("captureViewKeyEvent", this);
   3733         }
   3734 
   3735         if (mOnKeyListener != null && (mViewFlags & ENABLED_MASK) == ENABLED
   3736                 && mOnKeyListener.onKey(this, event.getKeyCode(), event)) {
   3737             return true;
   3738         }
   3739 
   3740         return event.dispatch(this, mAttachInfo != null
   3741                 ? mAttachInfo.mKeyDispatchState : null, this);
   3742     }
   3743 
   3744     /**
   3745      * Dispatches a key shortcut event.
   3746      *
   3747      * @param event The key event to be dispatched.
   3748      * @return True if the event was handled by the view, false otherwise.
   3749      */
   3750     public boolean dispatchKeyShortcutEvent(KeyEvent event) {
   3751         return onKeyShortcut(event.getKeyCode(), event);
   3752     }
   3753 
   3754     /**
   3755      * Pass the touch screen motion event down to the target view, or this
   3756      * view if it is the target.
   3757      *
   3758      * @param event The motion event to be dispatched.
   3759      * @return True if the event was handled by the view, false otherwise.
   3760      */
   3761     public boolean dispatchTouchEvent(MotionEvent event) {
   3762         if (mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED &&
   3763                 mOnTouchListener.onTouch(this, event)) {
   3764             return true;
   3765         }
   3766         return onTouchEvent(event);
   3767     }
   3768 
   3769     /**
   3770      * Pass a trackball motion event down to the focused view.
   3771      *
   3772      * @param event The motion event to be dispatched.
   3773      * @return True if the event was handled by the view, false otherwise.
   3774      */
   3775     public boolean dispatchTrackballEvent(MotionEvent event) {
   3776         //Log.i("view", "view=" + this + ", " + event.toString());
   3777         return onTrackballEvent(event);
   3778     }
   3779 
   3780     /**
   3781      * Called when the window containing this view gains or loses window focus.
   3782      * ViewGroups should override to route to their children.
   3783      *
   3784      * @param hasFocus True if the window containing this view now has focus,
   3785      *        false otherwise.
   3786      */
   3787     public void dispatchWindowFocusChanged(boolean hasFocus) {
   3788         onWindowFocusChanged(hasFocus);
   3789     }
   3790 
   3791     /**
   3792      * Called when the window containing this view gains or loses focus.  Note
   3793      * that this is separate from view focus: to receive key events, both
   3794      * your view and its window must have focus.  If a window is displayed
   3795      * on top of yours that takes input focus, then your own window will lose
   3796      * focus but the view focus will remain unchanged.
   3797      *
   3798      * @param hasWindowFocus True if the window containing this view now has
   3799      *        focus, false otherwise.
   3800      */
   3801     public void onWindowFocusChanged(boolean hasWindowFocus) {
   3802         InputMethodManager imm = InputMethodManager.peekInstance();
   3803         if (!hasWindowFocus) {
   3804             if (isPressed()) {
   3805                 setPressed(false);
   3806             }
   3807             if (imm != null && (mPrivateFlags & FOCUSED) != 0) {
   3808                 imm.focusOut(this);
   3809             }
   3810             removeLongPressCallback();
   3811             onFocusLost();
   3812         } else if (imm != null && (mPrivateFlags & FOCUSED) != 0) {
   3813             imm.focusIn(this);
   3814         }
   3815         refreshDrawableState();
   3816     }
   3817 
   3818     /**
   3819      * Returns true if this view is in a window that currently has window focus.
   3820      * Note that this is not the same as the view itself having focus.
   3821      *
   3822      * @return True if this view is in a window that currently has window focus.
   3823      */
   3824     public boolean hasWindowFocus() {
   3825         return mAttachInfo != null && mAttachInfo.mHasWindowFocus;
   3826     }
   3827 
   3828     /**
   3829      * Dispatch a view visibility change down the view hierarchy.
   3830      * ViewGroups should override to route to their children.
   3831      * @param changedView The view whose visibility changed. Could be 'this' or
   3832      * an ancestor view.
   3833      * @param visibility The new visibility of changedView: {@link #VISIBLE},
   3834      * {@link #INVISIBLE} or {@link #GONE}.
   3835      */
   3836     protected void dispatchVisibilityChanged(View changedView, int visibility) {
   3837         onVisibilityChanged(changedView, visibility);
   3838     }
   3839 
   3840     /**
   3841      * Called when the visibility of the view or an ancestor of the view is changed.
   3842      * @param changedView The view whose visibility changed. Could be 'this' or
   3843      * an ancestor view.
   3844      * @param visibility The new visibility of changedView: {@link #VISIBLE},
   3845      * {@link #INVISIBLE} or {@link #GONE}.
   3846      */
   3847     protected void onVisibilityChanged(View changedView, int visibility) {
   3848         if (visibility == VISIBLE) {
   3849             if (mAttachInfo != null) {
   3850                 initialAwakenScrollBars();
   3851             } else {
   3852                 mPrivateFlags |= AWAKEN_SCROLL_BARS_ON_ATTACH;
   3853             }
   3854         }
   3855     }
   3856 
   3857     /**
   3858      * Dispatch a hint about whether this view is displayed. For instance, when
   3859      * a View moves out of the screen, it might receives a display hint indicating
   3860      * the view is not displayed. Applications should not <em>rely</em> on this hint
   3861      * as there is no guarantee that they will receive one.
   3862      *
   3863      * @param hint A hint about whether or not this view is displayed:
   3864      * {@link #VISIBLE} or {@link #INVISIBLE}.
   3865      */
   3866     public void dispatchDisplayHint(int hint) {
   3867         onDisplayHint(hint);
   3868     }
   3869 
   3870     /**
   3871      * Gives this view a hint about whether is displayed or not. For instance, when
   3872      * a View moves out of the screen, it might receives a display hint indicating
   3873      * the view is not displayed. Applications should not <em>rely</em> on this hint
   3874      * as there is no guarantee that they will receive one.
   3875      *
   3876      * @param hint A hint about whether or not this view is displayed:
   3877      * {@link #VISIBLE} or {@link #INVISIBLE}.
   3878      */
   3879     protected void onDisplayHint(int hint) {
   3880     }
   3881 
   3882     /**
   3883      * Dispatch a window visibility change down the view hierarchy.
   3884      * ViewGroups should override to route to their children.
   3885      *
   3886      * @param visibility The new visibility of the window.
   3887      *
   3888      * @see #onWindowVisibilityChanged
   3889      */
   3890     public void dispatchWindowVisibilityChanged(int visibility) {
   3891         onWindowVisibilityChanged(visibility);
   3892     }
   3893 
   3894     /**
   3895      * Called when the window containing has change its visibility
   3896      * (between {@link #GONE}, {@link #INVISIBLE}, and {@link #VISIBLE}).  Note
   3897      * that this tells you whether or not your window is being made visible
   3898      * to the window manager; this does <em>not</em> tell you whether or not
   3899      * your window is obscured by other windows on the screen, even if it
   3900      * is itself visible.
   3901      *
   3902      * @param visibility The new visibility of the window.
   3903      */
   3904     protected void onWindowVisibilityChanged(int visibility) {
   3905         if (visibility == VISIBLE) {
   3906             initialAwakenScrollBars();
   3907         }
   3908     }
   3909 
   3910     /**
   3911      * Returns the current visibility of the window this view is attached to
   3912      * (either {@link #GONE}, {@link #INVISIBLE}, or {@link #VISIBLE}).
   3913      *
   3914      * @return Returns the current visibility of the view's window.
   3915      */
   3916     public int getWindowVisibility() {
   3917         return mAttachInfo != null ? mAttachInfo.mWindowVisibility : GONE;
   3918     }
   3919 
   3920     /**
   3921      * Retrieve the overall visible display size in which the window this view is
   3922      * attached to has been positioned in.  This takes into account screen
   3923      * decorations above the window, for both cases where the window itself
   3924      * is being position inside of them or the window is being placed under
   3925      * then and covered insets are used for the window to position its content
   3926      * inside.  In effect, this tells you the available area where content can
   3927      * be placed and remain visible to users.
   3928      *
   3929      * <p>This function requires an IPC back to the window manager to retrieve
   3930      * the requested information, so should not be used in performance critical
   3931      * code like drawing.
   3932      *
   3933      * @param outRect Filled in with the visible display frame.  If the view
   3934      * is not attached to a window, this is simply the raw display size.
   3935      */
   3936     public void getWindowVisibleDisplayFrame(Rect outRect) {
   3937         if (mAttachInfo != null) {
   3938             try {
   3939                 mAttachInfo.mSession.getDisplayFrame(mAttachInfo.mWindow, outRect);
   3940             } catch (RemoteException e) {
   3941                 return;
   3942             }
   3943             // XXX This is really broken, and probably all needs to be done
   3944             // in the window manager, and we need to know more about whether
   3945             // we want the area behind or in front of the IME.
   3946             final Rect insets = mAttachInfo.mVisibleInsets;
   3947             outRect.left += insets.left;
   3948             outRect.top += insets.top;
   3949             outRect.right -= insets.right;
   3950             outRect.bottom -= insets.bottom;
   3951             return;
   3952         }
   3953         Display d = WindowManagerImpl.getDefault().getDefaultDisplay();
   3954         outRect.set(0, 0, d.getWidth(), d.getHeight());
   3955     }
   3956 
   3957     /**
   3958      * Dispatch a notification about a resource configuration change down
   3959      * the view hierarchy.
   3960      * ViewGroups should override to route to their children.
   3961      *
   3962      * @param newConfig The new resource configuration.
   3963      *
   3964      * @see #onConfigurationChanged
   3965      */
   3966     public void dispatchConfigurationChanged(Configuration newConfig) {
   3967         onConfigurationChanged(newConfig);
   3968     }
   3969 
   3970     /**
   3971      * Called when the current configuration of the resources being used
   3972      * by the application have changed.  You can use this to decide when
   3973      * to reload resources that can changed based on orientation and other
   3974      * configuration characterstics.  You only need to use this if you are
   3975      * not relying on the normal {@link android.app.Activity} mechanism of
   3976      * recreating the activity instance upon a configuration change.
   3977      *
   3978      * @param newConfig The new resource configuration.
   3979      */
   3980     protected void onConfigurationChanged(Configuration newConfig) {
   3981     }
   3982 
   3983     /**
   3984      * Private function to aggregate all per-view attributes in to the view
   3985      * root.
   3986      */
   3987     void dispatchCollectViewAttributes(int visibility) {
   3988         performCollectViewAttributes(visibility);
   3989     }
   3990 
   3991     void performCollectViewAttributes(int visibility) {
   3992         //noinspection PointlessBitwiseExpression
   3993         if (((visibility | mViewFlags) & (VISIBILITY_MASK | KEEP_SCREEN_ON))
   3994                 == (VISIBLE | KEEP_SCREEN_ON)) {
   3995             mAttachInfo.mKeepScreenOn = true;
   3996         }
   3997     }
   3998 
   3999     void needGlobalAttributesUpdate(boolean force) {
   4000         AttachInfo ai = mAttachInfo;
   4001         if (ai != null) {
   4002             if (ai.mKeepScreenOn || force) {
   4003                 ai.mRecomputeGlobalAttributes = true;
   4004             }
   4005         }
   4006     }
   4007 
   4008     /**
   4009      * Returns whether the device is currently in touch mode.  Touch mode is entered
   4010      * once the user begins interacting with the device by touch, and affects various
   4011      * things like whether focus is always visible to the user.
   4012      *
   4013      * @return Whether the device is in touch mode.
   4014      */
   4015     @ViewDebug.ExportedProperty
   4016     public boolean isInTouchMode() {
   4017         if (mAttachInfo != null) {
   4018             return mAttachInfo.mInTouchMode;
   4019         } else {
   4020             return ViewRoot.isInTouchMode();
   4021         }
   4022     }
   4023 
   4024     /**
   4025      * Returns the context the view is running in, through which it can
   4026      * access the current theme, resources, etc.
   4027      *
   4028      * @return The view's Context.
   4029      */
   4030     @ViewDebug.CapturedViewProperty
   4031     public final Context getContext() {
   4032         return mContext;
   4033     }
   4034 
   4035     /**
   4036      * Handle a key event before it is processed by any input method
   4037      * associated with the view hierarchy.  This can be used to intercept
   4038      * key events in special situations before the IME consumes them; a
   4039      * typical example would be handling the BACK key to update the application's
   4040      * UI instead of allowing the IME to see it and close itself.
   4041      *
   4042      * @param keyCode The value in event.getKeyCode().
   4043      * @param event Description of the key event.
   4044      * @return If you handled the event, return true. If you want to allow the
   4045      *         event to be handled by the next receiver, return false.
   4046      */
   4047     public boolean onKeyPreIme(int keyCode, KeyEvent event) {
   4048         return false;
   4049     }
   4050 
   4051     /**
   4052      * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)
   4053      * KeyEvent.Callback.onKeyMultiple()}: perform press of the view
   4054      * when {@link KeyEvent#KEYCODE_DPAD_CENTER} or {@link KeyEvent#KEYCODE_ENTER}
   4055      * is released, if the view is enabled and clickable.
   4056      *
   4057      * @param keyCode A key code that represents the button pressed, from
   4058      *                {@link android.view.KeyEvent}.
   4059      * @param event   The KeyEvent object that defines the button action.
   4060      */
   4061     public boolean onKeyDown(int keyCode, KeyEvent event) {
   4062         boolean result = false;
   4063 
   4064         switch (keyCode) {
   4065             case KeyEvent.KEYCODE_DPAD_CENTER:
   4066             case KeyEvent.KEYCODE_ENTER: {
   4067                 if ((mViewFlags & ENABLED_MASK) == DISABLED) {
   4068                     return true;
   4069                 }
   4070                 // Long clickable items don't necessarily have to be clickable
   4071                 if (((mViewFlags & CLICKABLE) == CLICKABLE ||
   4072                         (mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) &&
   4073                         (event.getRepeatCount() == 0)) {
   4074                     setPressed(true);
   4075                     if ((mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) {
   4076                         postCheckForLongClick(0);
   4077                     }
   4078                     return true;
   4079                 }
   4080                 break;
   4081             }
   4082         }
   4083         return result;
   4084     }
   4085 
   4086     /**
   4087      * Default implementation of {@link KeyEvent.Callback#onKeyLongPress(int, KeyEvent)
   4088      * KeyEvent.Callback.onKeyLongPress()}: always returns false (doesn't handle
   4089      * the event).
   4090      */
   4091     public boolean onKeyLongPress(int keyCode, KeyEvent event) {
   4092         return false;
   4093     }
   4094 
   4095     /**
   4096      * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)
   4097      * KeyEvent.Callback.onKeyMultiple()}: perform clicking of the view
   4098      * when {@link KeyEvent#KEYCODE_DPAD_CENTER} or
   4099      * {@link KeyEvent#KEYCODE_ENTER} is released.
   4100      *
   4101      * @param keyCode A key code that represents the button pressed, from
   4102      *                {@link android.view.KeyEvent}.
   4103      * @param event   The KeyEvent object that defines the button action.
   4104      */
   4105     public boolean onKeyUp(int keyCode, KeyEvent event) {
   4106         boolean result = false;
   4107 
   4108         switch (keyCode) {
   4109             case KeyEvent.KEYCODE_DPAD_CENTER:
   4110             case KeyEvent.KEYCODE_ENTER: {
   4111                 if ((mViewFlags & ENABLED_MASK) == DISABLED) {
   4112                     return true;
   4113                 }
   4114                 if ((mViewFlags & CLICKABLE) == CLICKABLE && isPressed()) {
   4115                     setPressed(false);
   4116 
   4117                     if (!mHasPerformedLongPress) {
   4118                         // This is a tap, so remove the longpress check
   4119                         removeLongPressCallback();
   4120 
   4121                         result = performClick();
   4122                     }
   4123                 }
   4124                 break;
   4125             }
   4126         }
   4127         return result;
   4128     }
   4129 
   4130     /**
   4131      * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)
   4132      * KeyEvent.Callback.onKeyMultiple()}: always returns false (doesn't handle
   4133      * the event).
   4134      *
   4135      * @param keyCode     A key code that represents the button pressed, from
   4136      *                    {@link android.view.KeyEvent}.
   4137      * @param repeatCount The number of times the action was made.
   4138      * @param event       The KeyEvent object that defines the button action.
   4139      */
   4140     public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) {
   4141         return false;
   4142     }
   4143 
   4144     /**
   4145      * Called when an unhandled key shortcut event occurs.
   4146      *
   4147      * @param keyCode The value in event.getKeyCode().
   4148      * @param event Description of the key event.
   4149      * @return If you handled the event, return true. If you want to allow the
   4150      *         event to be handled by the next receiver, return false.
   4151      */
   4152     public boolean onKeyShortcut(int keyCode, KeyEvent event) {
   4153         return false;
   4154     }
   4155 
   4156     /**
   4157      * Check whether the called view is a text editor, in which case it
   4158      * would make sense to automatically display a soft input window for
   4159      * it.  Subclasses should override this if they implement
   4160      * {@link #onCreateInputConnection(EditorInfo)} to return true if
   4161      * a call on that method would return a non-null InputConnection, and
   4162      * they are really a first-class editor that the user would normally
   4163      * start typing on when the go into a window containing your view.
   4164      *
   4165      * <p>The default implementation always returns false.  This does
   4166      * <em>not</em> mean that its {@link #onCreateInputConnection(EditorInfo)}
   4167      * will not be called or the user can not otherwise perform edits on your
   4168      * view; it is just a hint to the system that this is not the primary
   4169      * purpose of this view.
   4170      *
   4171      * @return Returns true if this view is a text editor, else false.
   4172      */
   4173     public boolean onCheckIsTextEditor() {
   4174         return false;
   4175     }
   4176 
   4177     /**
   4178      * Create a new InputConnection for an InputMethod to interact
   4179      * with the view.  The default implementation returns null, since it doesn't
   4180      * support input methods.  You can override this to implement such support.
   4181      * This is only needed for views that take focus and text input.
   4182      *
   4183      * <p>When implementing this, you probably also want to implement
   4184      * {@link #onCheckIsTextEditor()} to indicate you will return a
   4185      * non-null InputConnection.
   4186      *
   4187      * @param outAttrs Fill in with attribute information about the connection.
   4188      */
   4189     public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
   4190         return null;
   4191     }
   4192 
   4193     /**
   4194      * Called by the {@link android.view.inputmethod.InputMethodManager}
   4195      * when a view who is not the current
   4196      * input connection target is trying to make a call on the manager.  The
   4197      * default implementation returns false; you can override this to return
   4198      * true for certain views if you are performing InputConnection proxying
   4199      * to them.
   4200      * @param view The View that is making the InputMethodManager call.
   4201      * @return Return true to allow the call, false to reject.
   4202      */
   4203     public boolean checkInputConnectionProxy(View view) {
   4204         return false;
   4205     }
   4206 
   4207     /**
   4208      * Show the context menu for this view. It is not safe to hold on to the
   4209      * menu after returning from this method.
   4210      *
   4211      * @param menu The context menu to populate
   4212      */
   4213     public void createContextMenu(ContextMenu menu) {
   4214         ContextMenuInfo menuInfo = getContextMenuInfo();
   4215 
   4216         // Sets the current menu info so all items added to menu will have
   4217         // my extra info set.
   4218         ((MenuBuilder)menu).setCurrentMenuInfo(menuInfo);
   4219 
   4220         onCreateContextMenu(menu);
   4221         if (mOnCreateContextMenuListener != null) {
   4222             mOnCreateContextMenuListener.onCreateContextMenu(menu, this, menuInfo);
   4223         }
   4224 
   4225         // Clear the extra information so subsequent items that aren't mine don't
   4226         // have my extra info.
   4227         ((MenuBuilder)menu).setCurrentMenuInfo(null);
   4228 
   4229         if (mParent != null) {
   4230             mParent.createContextMenu(menu);
   4231         }
   4232     }
   4233 
   4234     /**
   4235      * Views should implement this if they have extra information to associate
   4236      * with the context menu. The return result is supplied as a parameter to
   4237      * the {@link OnCreateContextMenuListener#onCreateContextMenu(ContextMenu, View, ContextMenuInfo)}
   4238      * callback.
   4239      *
   4240      * @return Extra information about the item for which the context menu
   4241      *         should be shown. This information will vary across different
   4242      *         subclasses of View.
   4243      */
   4244     protected ContextMenuInfo getContextMenuInfo() {
   4245         return null;
   4246     }
   4247 
   4248     /**
   4249      * Views should implement this if the view itself is going to add items to
   4250      * the context menu.
   4251      *
   4252      * @param menu the context menu to populate
   4253      */
   4254     protected void onCreateContextMenu(ContextMenu menu) {
   4255     }
   4256 
   4257     /**
   4258      * Implement this method to handle trackball motion events.  The
   4259      * <em>relative</em> movement of the trackball since the last event
   4260      * can be retrieve with {@link MotionEvent#getX MotionEvent.getX()} and
   4261      * {@link MotionEvent#getY MotionEvent.getY()}.  These are normalized so
   4262      * that a movement of 1 corresponds to the user pressing one DPAD key (so
   4263      * they will often be fractional values, representing the more fine-grained
   4264      * movement information available from a trackball).
   4265      *
   4266      * @param event The motion event.
   4267      * @return True if the event was handled, false otherwise.
   4268      */
   4269     public boolean onTrackballEvent(MotionEvent event) {
   4270         return false;
   4271     }
   4272 
   4273     /**
   4274      * Implement this method to handle touch screen motion events.
   4275      *
   4276      * @param event The motion event.
   4277      * @return True if the event was handled, false otherwise.
   4278      */
   4279     public boolean onTouchEvent(MotionEvent event) {
   4280         final int viewFlags = mViewFlags;
   4281 
   4282         if ((viewFlags & ENABLED_MASK) == DISABLED) {
   4283             // A disabled view that is clickable still consumes the touch
   4284             // events, it just doesn't respond to them.
   4285             return (((viewFlags & CLICKABLE) == CLICKABLE ||
   4286                     (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE));
   4287         }
   4288 
   4289         if (mTouchDelegate != null) {
   4290             if (mTouchDelegate.onTouchEvent(event)) {
   4291                 return true;
   4292             }
   4293         }
   4294 
   4295         if (((viewFlags & CLICKABLE) == CLICKABLE ||
   4296                 (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)) {
   4297             switch (event.getAction()) {
   4298                 case MotionEvent.ACTION_UP:
   4299                     boolean prepressed = (mPrivateFlags & PREPRESSED) != 0;
   4300                     if ((mPrivateFlags & PRESSED) != 0 || prepressed) {
   4301                         // take focus if we don't have it already and we should in
   4302                         // touch mode.
   4303                         boolean focusTaken = false;
   4304                         if (isFocusable() && isFocusableInTouchMode() && !isFocused()) {
   4305                             focusTaken = requestFocus();
   4306                         }
   4307 
   4308                         if (!mHasPerformedLongPress) {
   4309                             // This is a tap, so remove the longpress check
   4310                             removeLongPressCallback();
   4311 
   4312                             // Only perform take click actions if we were in the pressed state
   4313                             if (!focusTaken) {
   4314                                 // Use a Runnable and post this rather than calling
   4315                                 // performClick directly. This lets other visual state
   4316                                 // of the view update before click actions start.
   4317                                 if (mPerformClick == null) {
   4318                                     mPerformClick = new PerformClick();
   4319                                 }
   4320                                 if (!post(mPerformClick)) {
   4321                                     performClick();
   4322                                 }
   4323                             }
   4324                         }
   4325 
   4326                         if (mUnsetPressedState == null) {
   4327                             mUnsetPressedState = new UnsetPressedState();
   4328                         }
   4329 
   4330                         if (prepressed) {
   4331                             mPrivateFlags |= PRESSED;
   4332                             refreshDrawableState();
   4333                             postDelayed(mUnsetPressedState,
   4334                                     ViewConfiguration.getPressedStateDuration());
   4335                         } else if (!post(mUnsetPressedState)) {
   4336                             // If the post failed, unpress right now
   4337                             mUnsetPressedState.run();
   4338                         }
   4339                         removeTapCallback();
   4340                     }
   4341                     break;
   4342 
   4343                 case MotionEvent.ACTION_DOWN:
   4344                     if (mPendingCheckForTap == null) {
   4345                         mPendingCheckForTap = new CheckForTap();
   4346                     }
   4347                     mPrivateFlags |= PREPRESSED;
   4348                     mHasPerformedLongPress = false;
   4349                     postDelayed(mPendingCheckForTap, ViewConfiguration.getTapTimeout());
   4350                     break;
   4351 
   4352                 case MotionEvent.ACTION_CANCEL:
   4353                     mPrivateFlags &= ~PRESSED;
   4354                     refreshDrawableState();
   4355                     removeTapCallback();
   4356                     break;
   4357 
   4358                 case MotionEvent.ACTION_MOVE:
   4359                     final int x = (int) event.getX();
   4360                     final int y = (int) event.getY();
   4361 
   4362                     // Be lenient about moving outside of buttons
   4363                     int slop = mTouchSlop;
   4364                     if ((x < 0 - slop) || (x >= getWidth() + slop) ||
   4365                             (y < 0 - slop) || (y >= getHeight() + slop)) {
   4366                         // Outside button
   4367                         removeTapCallback();
   4368                         if ((mPrivateFlags & PRESSED) != 0) {
   4369                             // Remove any future long press/tap checks
   4370                             removeLongPressCallback();
   4371 
   4372                             // Need to switch from pressed to not pressed
   4373                             mPrivateFlags &= ~PRESSED;
   4374                             refreshDrawableState();
   4375                         }
   4376                     }
   4377                     break;
   4378             }
   4379             return true;
   4380         }
   4381 
   4382         return false;
   4383     }
   4384 
   4385     /**
   4386      * Remove the longpress detection timer.
   4387      */
   4388     private void removeLongPressCallback() {
   4389         if (mPendingCheckForLongPress != null) {
   4390           removeCallbacks(mPendingCheckForLongPress);
   4391         }
   4392     }
   4393 
   4394     /**
   4395      * Remove the prepress detection timer.
   4396      */
   4397     private void removeUnsetPressCallback() {
   4398         if ((mPrivateFlags & PRESSED) != 0 && mUnsetPressedState != null) {
   4399             setPressed(false);
   4400             removeCallbacks(mUnsetPressedState);
   4401         }
   4402     }
   4403 
   4404     /**
   4405      * Remove the tap detection timer.
   4406      */
   4407     private void removeTapCallback() {
   4408         if (mPendingCheckForTap != null) {
   4409             mPrivateFlags &= ~PREPRESSED;
   4410             removeCallbacks(mPendingCheckForTap);
   4411         }
   4412     }
   4413 
   4414     /**
   4415      * Cancels a pending long press.  Your subclass can use this if you
   4416      * want the context menu to come up if the user presses and holds
   4417      * at the same place, but you don't want it to come up if they press
   4418      * and then move around enough to cause scrolling.
   4419      */
   4420     public void cancelLongPress() {
   4421         removeLongPressCallback();
   4422 
   4423         /*
   4424          * The prepressed state handled by the tap callback is a display
   4425          * construct, but the tap callback will post a long press callback
   4426          * less its own timeout. Remove it here.
   4427          */
   4428         removeTapCallback();
   4429     }
   4430 
   4431     /**
   4432      * Sets the TouchDelegate for this View.
   4433      */
   4434     public void setTouchDelegate(TouchDelegate delegate) {
   4435         mTouchDelegate = delegate;
   4436     }
   4437 
   4438     /**
   4439      * Gets the TouchDelegate for this View.
   4440      */
   4441     public TouchDelegate getTouchDelegate() {
   4442         return mTouchDelegate;
   4443     }
   4444 
   4445     /**
   4446      * Set flags controlling behavior of this view.
   4447      *
   4448      * @param flags Constant indicating the value which should be set
   4449      * @param mask Constant indicating the bit range that should be changed
   4450      */
   4451     void setFlags(int flags, int mask) {
   4452         int old = mViewFlags;
   4453         mViewFlags = (mViewFlags & ~mask) | (flags & mask);
   4454 
   4455         int changed = mViewFlags ^ old;
   4456         if (changed == 0) {
   4457             return;
   4458         }
   4459         int privateFlags = mPrivateFlags;
   4460 
   4461         /* Check if the FOCUSABLE bit has changed */
   4462         if (((changed & FOCUSABLE_MASK) != 0) &&
   4463                 ((privateFlags & HAS_BOUNDS) !=0)) {
   4464             if (((old & FOCUSABLE_MASK) == FOCUSABLE)
   4465                     && ((privateFlags & FOCUSED) != 0)) {
   4466                 /* Give up focus if we are no longer focusable */
   4467                 clearFocus();
   4468             } else if (((old & FOCUSABLE_MASK) == NOT_FOCUSABLE)
   4469                     && ((privateFlags & FOCUSED) == 0)) {
   4470                 /*
   4471                  * Tell the view system that we are now available to take focus
   4472                  * if no one else already has it.
   4473                  */
   4474                 if (mParent != null) mParent.focusableViewAvailable(this);
   4475             }
   4476         }
   4477 
   4478         if ((flags & VISIBILITY_MASK) == VISIBLE) {
   4479             if ((changed & VISIBILITY_MASK) != 0) {
   4480                 /*
   4481                  * If this view is becoming visible, set the DRAWN flag so that
   4482                  * the next invalidate() will not be skipped.
   4483                  */
   4484                 mPrivateFlags |= DRAWN;
   4485 
   4486                 needGlobalAttributesUpdate(true);
   4487 
   4488                 // a view becoming visible is worth notifying the parent
   4489                 // about in case nothing has focus.  even if this specific view
   4490                 // isn't focusable, it may contain something that is, so let
   4491                 // the root view try to give this focus if nothing else does.
   4492                 if ((mParent != null) && (mBottom > mTop) && (mRight > mLeft)) {
   4493                     mParent.focusableViewAvailable(this);
   4494                 }
   4495             }
   4496         }
   4497 
   4498         /* Check if the GONE bit has changed */
   4499         if ((changed & GONE) != 0) {
   4500             needGlobalAttributesUpdate(false);
   4501             requestLayout();
   4502             invalidate();
   4503 
   4504             if (((mViewFlags & VISIBILITY_MASK) == GONE)) {
   4505                 if (hasFocus()) clearFocus();
   4506                 destroyDrawingCache();
   4507             }
   4508             if (mAttachInfo != null) {
   4509                 mAttachInfo.mViewVisibilityChanged = true;
   4510             }
   4511         }
   4512 
   4513         /* Check if the VISIBLE bit has changed */
   4514         if ((changed & INVISIBLE) != 0) {
   4515             needGlobalAttributesUpdate(false);
   4516             invalidate();
   4517 
   4518             if (((mViewFlags & VISIBILITY_MASK) == INVISIBLE) && hasFocus()) {
   4519                 // root view becoming invisible shouldn't clear focus
   4520                 if (getRootView() != this) {
   4521                     clearFocus();
   4522                 }
   4523             }
   4524             if (mAttachInfo != null) {
   4525                 mAttachInfo.mViewVisibilityChanged = true;
   4526             }
   4527         }
   4528 
   4529         if ((changed & VISIBILITY_MASK) != 0) {
   4530             dispatchVisibilityChanged(this, (flags & VISIBILITY_MASK));
   4531         }
   4532 
   4533         if ((changed & WILL_NOT_CACHE_DRAWING) != 0) {
   4534             destroyDrawingCache();
   4535         }
   4536 
   4537         if ((changed & DRAWING_CACHE_ENABLED) != 0) {
   4538             destroyDrawingCache();
   4539             mPrivateFlags &= ~DRAWING_CACHE_VALID;
   4540         }
   4541 
   4542         if ((changed & DRAWING_CACHE_QUALITY_MASK) != 0) {
   4543             destroyDrawingCache();
   4544             mPrivateFlags &= ~DRAWING_CACHE_VALID;
   4545         }
   4546 
   4547         if ((changed & DRAW_MASK) != 0) {
   4548             if ((mViewFlags & WILL_NOT_DRAW) != 0) {
   4549                 if (mBGDrawable != null) {
   4550                     mPrivateFlags &= ~SKIP_DRAW;
   4551                     mPrivateFlags |= ONLY_DRAWS_BACKGROUND;
   4552                 } else {
   4553                     mPrivateFlags |= SKIP_DRAW;
   4554                 }
   4555             } else {
   4556                 mPrivateFlags &= ~SKIP_DRAW;
   4557             }
   4558             requestLayout();
   4559             invalidate();
   4560         }
   4561 
   4562         if ((changed & KEEP_SCREEN_ON) != 0) {
   4563             if (mParent != null) {
   4564                 mParent.recomputeViewAttributes(this);
   4565             }
   4566         }
   4567     }
   4568 
   4569     /**
   4570      * Change the view's z order in the tree, so it's on top of other sibling
   4571      * views
   4572      */
   4573     public void bringToFront() {
   4574         if (mParent != null) {
   4575             mParent.bringChildToFront(this);
   4576         }
   4577     }
   4578 
   4579     /**
   4580      * This is called in response to an internal scroll in this view (i.e., the
   4581      * view scrolled its own contents). This is typically as a result of
   4582      * {@link #scrollBy(int, int)} or {@link #scrollTo(int, int)} having been
   4583      * called.
   4584      *
   4585      * @param l Current horizontal scroll origin.
   4586      * @param t Current vertical scroll origin.
   4587      * @param oldl Previous horizontal scroll origin.
   4588      * @param oldt Previous vertical scroll origin.
   4589      */
   4590     protected void onScrollChanged(int l, int t, int oldl, int oldt) {
   4591         mBackgroundSizeChanged = true;
   4592 
   4593         final AttachInfo ai = mAttachInfo;
   4594         if (ai != null) {
   4595             ai.mViewScrollChanged = true;
   4596         }
   4597     }
   4598 
   4599     /**
   4600      * This is called during layout when the size of this view has changed. If
   4601      * you were just added to the view hierarchy, you're called with the old
   4602      * values of 0.
   4603      *
   4604      * @param w Current width of this view.
   4605      * @param h Current height of this view.
   4606      * @param oldw Old width of this view.
   4607      * @param oldh Old height of this view.
   4608      */
   4609     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
   4610     }
   4611 
   4612     /**
   4613      * Called by draw to draw the child views. This may be overridden
   4614      * by derived classes to gain control just before its children are drawn
   4615      * (but after its own view has been drawn).
   4616      * @param canvas the canvas on which to draw the view
   4617      */
   4618     protected void dispatchDraw(Canvas canvas) {
   4619     }
   4620 
   4621     /**
   4622      * Gets the parent of this view. Note that the parent is a
   4623      * ViewParent and not necessarily a View.
   4624      *
   4625      * @return Parent of this view.
   4626      */
   4627     public final ViewParent getParent() {
   4628         return mParent;
   4629     }
   4630 
   4631     /**
   4632      * Return the scrolled left position of this view. This is the left edge of
   4633      * the displayed part of your view. You do not need to draw any pixels
   4634      * farther left, since those are outside of the frame of your view on
   4635      * screen.
   4636      *
   4637      * @return The left edge of the displayed part of your view, in pixels.
   4638      */
   4639     public final int getScrollX() {
   4640         return mScrollX;
   4641     }
   4642 
   4643     /**
   4644      * Return the scrolled top position of this view. This is the top edge of
   4645      * the displayed part of your view. You do not need to draw any pixels above
   4646      * it, since those are outside of the frame of your view on screen.
   4647      *
   4648      * @return The top edge of the displayed part of your view, in pixels.
   4649      */
   4650     public final int getScrollY() {
   4651         return mScrollY;
   4652     }
   4653 
   4654     /**
   4655      * Return the width of the your view.
   4656      *
   4657      * @return The width of your view, in pixels.
   4658      */
   4659     @ViewDebug.ExportedProperty
   4660     public final int getWidth() {
   4661         return mRight - mLeft;
   4662     }
   4663 
   4664     /**
   4665      * Return the height of your view.
   4666      *
   4667      * @return The height of your view, in pixels.
   4668      */
   4669     @ViewDebug.ExportedProperty
   4670     public final int getHeight() {
   4671         return mBottom - mTop;
   4672     }
   4673 
   4674     /**
   4675      * Return the visible drawing bounds of your view. Fills in the output
   4676      * rectangle with the values from getScrollX(), getScrollY(),
   4677      * getWidth(), and getHeight().
   4678      *
   4679      * @param outRect The (scrolled) drawing bounds of the view.
   4680      */
   4681     public void getDrawingRect(Rect outRect) {
   4682         outRect.left = mScrollX;
   4683         outRect.top = mScrollY;
   4684         outRect.right = mScrollX + (mRight - mLeft);
   4685         outRect.bottom = mScrollY + (mBottom - mTop);
   4686     }
   4687 
   4688     /**
   4689      * The width of this view as measured in the most recent call to measure().
   4690      * This should be used during measurement and layout calculations only. Use
   4691      * {@link #getWidth()} to see how wide a view is after layout.
   4692      *
   4693      * @return The measured width of this view.
   4694      */
   4695     public final int getMeasuredWidth() {
   4696         return mMeasuredWidth;
   4697     }
   4698 
   4699     /**
   4700      * The height of this view as measured in the most recent call to measure().
   4701      * This should be used during measurement and layout calculations only. Use
   4702      * {@link #getHeight()} to see how tall a view is after layout.
   4703      *
   4704      * @return The measured height of this view.
   4705      */
   4706     public final int getMeasuredHeight() {
   4707         return mMeasuredHeight;
   4708     }
   4709 
   4710     /**
   4711      * Top position of this view relative to its parent.
   4712      *
   4713      * @return The top of this view, in pixels.
   4714      */
   4715     @ViewDebug.CapturedViewProperty
   4716     public final int getTop() {
   4717         return mTop;
   4718     }
   4719 
   4720     /**
   4721      * Bottom position of this view relative to its parent.
   4722      *
   4723      * @return The bottom of this view, in pixels.
   4724      */
   4725     @ViewDebug.CapturedViewProperty
   4726     public final int getBottom() {
   4727         return mBottom;
   4728     }
   4729 
   4730     /**
   4731      * Left position of this view relative to its parent.
   4732      *
   4733      * @return The left edge of this view, in pixels.
   4734      */
   4735     @ViewDebug.CapturedViewProperty
   4736     public final int getLeft() {
   4737         return mLeft;
   4738     }
   4739 
   4740     /**
   4741      * Right position of this view relative to its parent.
   4742      *
   4743      * @return The right edge of this view, in pixels.
   4744      */
   4745     @ViewDebug.CapturedViewProperty
   4746     public final int getRight() {
   4747         return mRight;
   4748     }
   4749 
   4750     /**
   4751      * Hit rectangle in parent's coordinates
   4752      *
   4753      * @param outRect The hit rectangle of the view.
   4754      */
   4755     public void getHitRect(Rect outRect) {
   4756         outRect.set(mLeft, mTop, mRight, mBottom);
   4757     }
   4758 
   4759     /**
   4760      * When a view has focus and the user navigates away from it, the next view is searched for
   4761      * starting from the rectangle filled in by this method.
   4762      *
   4763      * By default, the rectange is the {@link #getDrawingRect})of the view.  However, if your
   4764      * view maintains some idea of internal selection, such as a cursor, or a selected row
   4765      * or column, you should override this method and fill in a more specific rectangle.
   4766      *
   4767      * @param r The rectangle to fill in, in this view's coordinates.
   4768      */
   4769     public void getFocusedRect(Rect r) {
   4770         getDrawingRect(r);
   4771     }
   4772 
   4773     /**
   4774      * If some part of this view is not clipped by any of its parents, then
   4775      * return that area in r in global (root) coordinates. To convert r to local
   4776      * coordinates, offset it by -globalOffset (e.g. r.offset(-globalOffset.x,
   4777      * -globalOffset.y)) If the view is completely clipped or translated out,
   4778      * return false.
   4779      *
   4780      * @param r If true is returned, r holds the global coordinates of the
   4781      *        visible portion of this view.
   4782      * @param globalOffset If true is returned, globalOffset holds the dx,dy
   4783      *        between this view and its root. globalOffet may be null.
   4784      * @return true if r is non-empty (i.e. part of the view is visible at the
   4785      *         root level.
   4786      */
   4787     public boolean getGlobalVisibleRect(Rect r, Point globalOffset) {
   4788         int width = mRight - mLeft;
   4789         int height = mBottom - mTop;
   4790         if (width > 0 && height > 0) {
   4791             r.set(0, 0, width, height);
   4792             if (globalOffset != null) {
   4793                 globalOffset.set(-mScrollX, -mScrollY);
   4794             }
   4795             return mParent == null || mParent.getChildVisibleRect(this, r, globalOffset);
   4796         }
   4797         return false;
   4798     }
   4799 
   4800     public final boolean getGlobalVisibleRect(Rect r) {
   4801         return getGlobalVisibleRect(r, null);
   4802     }
   4803 
   4804     public final boolean getLocalVisibleRect(Rect r) {
   4805         Point offset = new Point();
   4806         if (getGlobalVisibleRect(r, offset)) {
   4807             r.offset(-offset.x, -offset.y); // make r local
   4808             return true;
   4809         }
   4810         return false;
   4811     }
   4812 
   4813     /**
   4814      * Offset this view's vertical location by the specified number of pixels.
   4815      *
   4816      * @param offset the number of pixels to offset the view by
   4817      */
   4818     public void offsetTopAndBottom(int offset) {
   4819         mTop += offset;
   4820         mBottom += offset;
   4821     }
   4822 
   4823     /**
   4824      * Offset this view's horizontal location by the specified amount of pixels.
   4825      *
   4826      * @param offset the numer of pixels to offset the view by
   4827      */
   4828     public void offsetLeftAndRight(int offset) {
   4829         mLeft += offset;
   4830         mRight += offset;
   4831     }
   4832 
   4833     /**
   4834      * Get the LayoutParams associated with this view. All views should have
   4835      * layout parameters. These supply parameters to the <i>parent</i> of this
   4836      * view specifying how it should be arranged. There are many subclasses of
   4837      * ViewGroup.LayoutParams, and these correspond to the different subclasses
   4838      * of ViewGroup that are responsible for arranging their children.
   4839      * @return The LayoutParams associated with this view
   4840      */
   4841     @ViewDebug.ExportedProperty(deepExport = true, prefix = "layout_")
   4842     public ViewGroup.LayoutParams getLayoutParams() {
   4843         return mLayoutParams;
   4844     }
   4845 
   4846     /**
   4847      * Set the layout parameters associated with this view. These supply
   4848      * parameters to the <i>parent</i> of this view specifying how it should be
   4849      * arranged. There are many subclasses of ViewGroup.LayoutParams, and these
   4850      * correspond to the different subclasses of ViewGroup that are responsible
   4851      * for arranging their children.
   4852      *
   4853      * @param params the layout parameters for this view
   4854      */
   4855     public void setLayoutParams(ViewGroup.LayoutParams params) {
   4856         if (params == null) {
   4857             throw new NullPointerException("params == null");
   4858         }
   4859         mLayoutParams = params;
   4860         requestLayout();
   4861     }
   4862 
   4863     /**
   4864      * Set the scrolled position of your view. This will cause a call to
   4865      * {@link #onScrollChanged(int, int, int, int)} and the view will be
   4866      * invalidated.
   4867      * @param x the x position to scroll to
   4868      * @param y the y position to scroll to
   4869      */
   4870     public void scrollTo(int x, int y) {
   4871         if (mScrollX != x || mScrollY != y) {
   4872             int oldX = mScrollX;
   4873             int oldY = mScrollY;
   4874             mScrollX = x;
   4875             mScrollY = y;
   4876             onScrollChanged(mScrollX, mScrollY, oldX, oldY);
   4877             if (!awakenScrollBars()) {
   4878                 invalidate();
   4879             }
   4880         }
   4881     }
   4882 
   4883     /**
   4884      * Move the scrolled position of your view. This will cause a call to
   4885      * {@link #onScrollChanged(int, int, int, int)} and the view will be
   4886      * invalidated.
   4887      * @param x the amount of pixels to scroll by horizontally
   4888      * @param y the amount of pixels to scroll by vertically
   4889      */
   4890     public void scrollBy(int x, int y) {
   4891         scrollTo(mScrollX + x, mScrollY + y);
   4892     }
   4893 
   4894     /**
   4895      * <p>Trigger the scrollbars to draw. When invoked this method starts an
   4896      * animation to fade the scrollbars out after a default delay. If a subclass
   4897      * provides animated scrolling, the start delay should equal the duration
   4898      * of the scrolling animation.</p>
   4899      *
   4900      * <p>The animation starts only if at least one of the scrollbars is
   4901      * enabled, as specified by {@link #isHorizontalScrollBarEnabled()} and
   4902      * {@link #isVerticalScrollBarEnabled()}. When the animation is started,
   4903      * this method returns true, and false otherwise. If the animation is
   4904      * started, this method calls {@link #invalidate()}; in that case the
   4905      * caller should not call {@link #invalidate()}.</p>
   4906      *
   4907      * <p>This method should be invoked every time a subclass directly updates
   4908      * the scroll parameters.</p>
   4909      *
   4910      * <p>This method is automatically invoked by {@link #scrollBy(int, int)}
   4911      * and {@link #scrollTo(int, int)}.</p>
   4912      *
   4913      * @return true if the animation is played, false otherwise
   4914      *
   4915      * @see #awakenScrollBars(int)
   4916      * @see #scrollBy(int, int)
   4917      * @see #scrollTo(int, int)
   4918      * @see #isHorizontalScrollBarEnabled()
   4919      * @see #isVerticalScrollBarEnabled()
   4920      * @see #setHorizontalScrollBarEnabled(boolean)
   4921      * @see #setVerticalScrollBarEnabled(boolean)
   4922      */
   4923     protected boolean awakenScrollBars() {
   4924         return mScrollCache != null &&
   4925                 awakenScrollBars(mScrollCache.scrollBarDefaultDelayBeforeFade, true);
   4926     }
   4927 
   4928     /**
   4929      * Trigger the scrollbars to draw.
   4930      * This method differs from awakenScrollBars() only in its default duration.
   4931      * initialAwakenScrollBars() will show the scroll bars for longer than
   4932      * usual to give the user more of a chance to notice them.
   4933      *
   4934      * @return true if the animation is played, false otherwise.
   4935      */
   4936     private boolean initialAwakenScrollBars() {
   4937         return mScrollCache != null &&
   4938                 awakenScrollBars(mScrollCache.scrollBarDefaultDelayBeforeFade * 4, true);
   4939     }
   4940 
   4941     /**
   4942      * <p>
   4943      * Trigger the scrollbars to draw. When invoked this method starts an
   4944      * animation to fade the scrollbars out after a fixed delay. If a subclass
   4945      * provides animated scrolling, the start delay should equal the duration of
   4946      * the scrolling animation.
   4947      * </p>
   4948      *
   4949      * <p>
   4950      * The animation starts only if at least one of the scrollbars is enabled,
   4951      * as specified by {@link #isHorizontalScrollBarEnabled()} and
   4952      * {@link #isVerticalScrollBarEnabled()}. When the animation is started,
   4953      * this method returns true, and false otherwise. If the animation is
   4954      * started, this method calls {@link #invalidate()}; in that case the caller
   4955      * should not call {@link #invalidate()}.
   4956      * </p>
   4957      *
   4958      * <p>
   4959      * This method should be invoked everytime a subclass directly updates the
   4960      * scroll parameters.
   4961      * </p>
   4962      *
   4963      * @param startDelay the delay, in milliseconds, after which the animation
   4964      *        should start; when the delay is 0, the animation starts
   4965      *        immediately
   4966      * @return true if the animation is played, false otherwise
   4967      *
   4968      * @see #scrollBy(int, int)
   4969      * @see #scrollTo(int, int)
   4970      * @see #isHorizontalScrollBarEnabled()
   4971      * @see #isVerticalScrollBarEnabled()
   4972      * @see #setHorizontalScrollBarEnabled(boolean)
   4973      * @see #setVerticalScrollBarEnabled(boolean)
   4974      */
   4975     protected boolean awakenScrollBars(int startDelay) {
   4976         return awakenScrollBars(startDelay, true);
   4977     }
   4978 
   4979     /**
   4980      * <p>
   4981      * Trigger the scrollbars to draw. When invoked this method starts an
   4982      * animation to fade the scrollbars out after a fixed delay. If a subclass
   4983      * provides animated scrolling, the start delay should equal the duration of
   4984      * the scrolling animation.
   4985      * </p>
   4986      *
   4987      * <p>
   4988      * The animation starts only if at least one of the scrollbars is enabled,
   4989      * as specified by {@link #isHorizontalScrollBarEnabled()} and
   4990      * {@link #isVerticalScrollBarEnabled()}. When the animation is started,
   4991      * this method returns true, and false otherwise. If the animation is
   4992      * started, this method calls {@link #invalidate()} if the invalidate parameter
   4993      * is set to true; in that case the caller
   4994      * should not call {@link #invalidate()}.
   4995      * </p>
   4996      *
   4997      * <p>
   4998      * This method should be invoked everytime a subclass directly updates the
   4999      * scroll parameters.
   5000      * </p>
   5001      *
   5002      * @param startDelay the delay, in milliseconds, after which the animation
   5003      *        should start; when the delay is 0, the animation starts
   5004      *        immediately
   5005      *
   5006      * @param invalidate Wheter this method should call invalidate
   5007      *
   5008      * @return true if the animation is played, false otherwise
   5009      *
   5010      * @see #scrollBy(int, int)
   5011      * @see #scrollTo(int, int)
   5012      * @see #isHorizontalScrollBarEnabled()
   5013      * @see #isVerticalScrollBarEnabled()
   5014      * @see #setHorizontalScrollBarEnabled(boolean)
   5015      * @see #setVerticalScrollBarEnabled(boolean)
   5016      */
   5017     protected boolean awakenScrollBars(int startDelay, boolean invalidate) {
   5018         final ScrollabilityCache scrollCache = mScrollCache;
   5019 
   5020         if (scrollCache == null || !scrollCache.fadeScrollBars) {
   5021             return false;
   5022         }
   5023 
   5024         if (scrollCache.scrollBar == null) {
   5025             scrollCache.scrollBar = new ScrollBarDrawable();
   5026         }
   5027 
   5028         if (isHorizontalScrollBarEnabled() || isVerticalScrollBarEnabled()) {
   5029 
   5030             if (invalidate) {
   5031                 // Invalidate to show the scrollbars
   5032                 invalidate();
   5033             }
   5034 
   5035             if (scrollCache.state == ScrollabilityCache.OFF) {
   5036                 // FIXME: this is copied from WindowManagerService.
   5037                 // We should get this value from the system when it
   5038                 // is possible to do so.
   5039                 final int KEY_REPEAT_FIRST_DELAY = 750;
   5040                 startDelay = Math.max(KEY_REPEAT_FIRST_DELAY, startDelay);
   5041             }
   5042 
   5043             // Tell mScrollCache when we should start fading. This may
   5044             // extend the fade start time if one was already scheduled
   5045             long fadeStartTime = AnimationUtils.currentAnimationTimeMillis() + startDelay;
   5046             scrollCache.fadeStartTime = fadeStartTime;
   5047             scrollCache.state = ScrollabilityCache.ON;
   5048 
   5049             // Schedule our fader to run, unscheduling any old ones first
   5050             if (mAttachInfo != null) {
   5051                 mAttachInfo.mHandler.removeCallbacks(scrollCache);
   5052                 mAttachInfo.mHandler.postAtTime(scrollCache, fadeStartTime);
   5053             }
   5054 
   5055             return true;
   5056         }
   5057 
   5058         return false;
   5059     }
   5060 
   5061     /**
   5062      * Mark the the area defined by dirty as needing to be drawn. If the view is
   5063      * visible, {@link #onDraw} will be called at some point in the future.
   5064      * This must be called from a UI thread. To call from a non-UI thread, call
   5065      * {@link #postInvalidate()}.
   5066      *
   5067      * WARNING: This method is destructive to dirty.
   5068      * @param dirty the rectangle representing the bounds of the dirty region
   5069      */
   5070     public void invalidate(Rect dirty) {
   5071         if (ViewDebug.TRACE_HIERARCHY) {
   5072             ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE);
   5073         }
   5074 
   5075         if ((mPrivateFlags & (DRAWN | HAS_BOUNDS)) == (DRAWN | HAS_BOUNDS)) {
   5076             mPrivateFlags &= ~DRAWING_CACHE_VALID;
   5077             final ViewParent p = mParent;
   5078             final AttachInfo ai = mAttachInfo;
   5079             if (p != null && ai != null) {
   5080                 final int scrollX = mScrollX;
   5081                 final int scrollY = mScrollY;
   5082                 final Rect r = ai.mTmpInvalRect;
   5083                 r.set(dirty.left - scrollX, dirty.top - scrollY,
   5084                         dirty.right - scrollX, dirty.bottom - scrollY);
   5085                 mParent.invalidateChild(this, r);
   5086             }
   5087         }
   5088     }
   5089 
   5090     /**
   5091      * Mark the the area defined by the rect (l,t,r,b) as needing to be drawn.
   5092      * The coordinates of the dirty rect are relative to the view.
   5093      * If the view is visible, {@link #onDraw} will be called at some point
   5094      * in the future. This must be called from a UI thread. To call
   5095      * from a non-UI thread, call {@link #postInvalidate()}.
   5096      * @param l the left position of the dirty region
   5097      * @param t the top position of the dirty region
   5098      * @param r the right position of the dirty region
   5099      * @param b the bottom position of the dirty region
   5100      */
   5101     public void invalidate(int l, int t, int r, int b) {
   5102         if (ViewDebug.TRACE_HIERARCHY) {
   5103             ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE);
   5104         }
   5105 
   5106         if ((mPrivateFlags & (DRAWN | HAS_BOUNDS)) == (DRAWN | HAS_BOUNDS)) {
   5107             mPrivateFlags &= ~DRAWING_CACHE_VALID;
   5108             final ViewParent p = mParent;
   5109             final AttachInfo ai = mAttachInfo;
   5110             if (p != null && ai != null && l < r && t < b) {
   5111                 final int scrollX = mScrollX;
   5112                 final int scrollY = mScrollY;
   5113                 final Rect tmpr = ai.mTmpInvalRect;
   5114                 tmpr.set(l - scrollX, t - scrollY, r - scrollX, b - scrollY);
   5115                 p.invalidateChild(this, tmpr);
   5116             }
   5117         }
   5118     }
   5119 
   5120     /**
   5121      * Invalidate the whole view. If the view is visible, {@link #onDraw} will
   5122      * be called at some point in the future. This must be called from a
   5123      * UI thread. To call from a non-UI thread, call {@link #postInvalidate()}.
   5124      */
   5125     public void invalidate() {
   5126         if (ViewDebug.TRACE_HIERARCHY) {
   5127             ViewDebug.trace(this, ViewDebug.HierarchyTraceType.INVALIDATE);
   5128         }
   5129 
   5130         if ((mPrivateFlags & (DRAWN | HAS_BOUNDS)) == (DRAWN | HAS_BOUNDS)) {
   5131             mPrivateFlags &= ~DRAWN & ~DRAWING_CACHE_VALID;
   5132             final ViewParent p = mParent;
   5133             final AttachInfo ai = mAttachInfo;
   5134             if (p != null && ai != null) {
   5135                 final Rect r = ai.mTmpInvalRect;
   5136                 r.set(0, 0, mRight - mLeft, mBottom - mTop);
   5137                 // Don't call invalidate -- we don't want to internally scroll
   5138                 // our own bounds
   5139                 p.invalidateChild(this, r);
   5140             }
   5141         }
   5142     }
   5143 
   5144     /**
   5145      * Indicates whether this View is opaque. An opaque View guarantees that it will
   5146      * draw all the pixels overlapping its bounds using a fully opaque color.
   5147      *
   5148      * Subclasses of View should override this method whenever possible to indicate
   5149      * whether an instance is opaque. Opaque Views are treated in a special way by
   5150      * the View hierarchy, possibly allowing it to perform optimizations during
   5151      * invalidate/draw passes.
   5152      *
   5153      * @return True if this View is guaranteed to be fully opaque, false otherwise.
   5154      */
   5155     @ViewDebug.ExportedProperty
   5156     public boolean isOpaque() {
   5157         return (mPrivateFlags & OPAQUE_MASK) == OPAQUE_MASK;
   5158     }
   5159 
   5160     private void computeOpaqueFlags() {
   5161         // Opaque if:
   5162         //   - Has a background
   5163         //   - Background is opaque
   5164         //   - Doesn't have scrollbars or scrollbars are inside overlay
   5165 
   5166         if (mBGDrawable != null && mBGDrawable.getOpacity() == PixelFormat.OPAQUE) {
   5167             mPrivateFlags |= OPAQUE_BACKGROUND;
   5168         } else {
   5169             mPrivateFlags &= ~OPAQUE_BACKGROUND;
   5170         }
   5171 
   5172         final int flags = mViewFlags;
   5173         if (((flags & SCROLLBARS_VERTICAL) == 0 && (flags & SCROLLBARS_HORIZONTAL) == 0) ||
   5174                 (flags & SCROLLBARS_STYLE_MASK) == SCROLLBARS_INSIDE_OVERLAY) {
   5175             mPrivateFlags |= OPAQUE_SCROLLBARS;
   5176         } else {
   5177             mPrivateFlags &= ~OPAQUE_SCROLLBARS;
   5178         }
   5179     }
   5180 
   5181     /**
   5182      * @hide
   5183      */
   5184     protected boolean hasOpaqueScrollbars() {
   5185         return (mPrivateFlags & OPAQUE_SCROLLBARS) == OPAQUE_SCROLLBARS;
   5186     }
   5187 
   5188     /**
   5189      * @return A handler associated with the thread running the View. This
   5190      * handler can be used to pump events in the UI events queue.
   5191      */
   5192     public Handler getHandler() {
   5193         if (mAttachInfo != null) {
   5194             return mAttachInfo.mHandler;
   5195         }
   5196         return null;
   5197     }
   5198 
   5199     /**
   5200      * Causes the Runnable to be added to the message queue.
   5201      * The runnable will be run on the user interface thread.
   5202      *
   5203      * @param action The Runnable that will be executed.
   5204      *
   5205      * @return Returns true if the Runnable was successfully placed in to the
   5206      *         message queue.  Returns false on failure, usually because the
   5207      *         looper processing the message queue is exiting.
   5208      */
   5209     public boolean post(Runnable action) {
   5210         Handler handler;
   5211         if (mAttachInfo != null) {
   5212             handler = mAttachInfo.mHandler;
   5213         } else {
   5214             // Assume that post will succeed later
   5215             ViewRoot.getRunQueue().post(action);
   5216             return true;
   5217         }
   5218 
   5219         return handler.post(action);
   5220     }
   5221 
   5222     /**
   5223      * Causes the Runnable to be added to the message queue, to be run
   5224      * after the specified amount of time elapses.
   5225      * The runnable will be run on the user interface thread.
   5226      *
   5227      * @param action The Runnable that will be executed.
   5228      * @param delayMillis The delay (in milliseconds) until the Runnable
   5229      *        will be executed.
   5230      *
   5231      * @return true if the Runnable was successfully placed in to the
   5232      *         message queue.  Returns false on failure, usually because the
   5233      *         looper processing the message queue is exiting.  Note that a
   5234      *         result of true does not mean the Runnable will be processed --
   5235      *         if the looper is quit before the delivery time of the message
   5236      *         occurs then the message will be dropped.
   5237      */
   5238     public boolean postDelayed(Runnable action, long delayMillis) {
   5239         Handler handler;
   5240         if (mAttachInfo != null) {
   5241             handler = mAttachInfo.mHandler;
   5242         } else {
   5243             // Assume that post will succeed later
   5244             ViewRoot.getRunQueue().postDelayed(action, delayMillis);
   5245             return true;
   5246         }
   5247 
   5248         return handler.postDelayed(action, delayMillis);
   5249     }
   5250 
   5251     /**
   5252      * Removes the specified Runnable from the message queue.
   5253      *
   5254      * @param action The Runnable to remove from the message handling queue
   5255      *
   5256      * @return true if this view could ask the Handler to remove the Runnable,
   5257      *         false otherwise. When the returned value is true, the Runnable
   5258      *         may or may not have been actually removed from the message queue
   5259      *         (for instance, if the Runnable was not in the queue already.)
   5260      */
   5261     public boolean removeCallbacks(Runnable action) {
   5262         Handler handler;
   5263         if (mAttachInfo != null) {
   5264             handler = mAttachInfo.mHandler;
   5265         } else {
   5266             // Assume that post will succeed later
   5267             ViewRoot.getRunQueue().removeCallbacks(action);
   5268             return true;
   5269         }
   5270 
   5271         handler.removeCallbacks(action);
   5272         return true;
   5273     }
   5274 
   5275     /**
   5276      * Cause an invalidate to happen on a subsequent cycle through the event loop.
   5277      * Use this to invalidate the View from a non-UI thread.
   5278      *
   5279      * @see #invalidate()
   5280      */
   5281     public void postInvalidate() {
   5282         postInvalidateDelayed(0);
   5283     }
   5284 
   5285     /**
   5286      * Cause an invalidate of the specified area to happen on a subsequent cycle
   5287      * through the event loop. Use this to invalidate the View from a non-UI thread.
   5288      *
   5289      * @param left The left coordinate of the rectangle to invalidate.
   5290      * @param top The top coordinate of the rectangle to invalidate.
   5291      * @param right The right coordinate of the rectangle to invalidate.
   5292      * @param bottom The bottom coordinate of the rectangle to invalidate.
   5293      *
   5294      * @see #invalidate(int, int, int, int)
   5295      * @see #invalidate(Rect)
   5296      */
   5297     public void postInvalidate(int left, int top, int right, int bottom) {
   5298         postInvalidateDelayed(0, left, top, right, bottom);
   5299     }
   5300 
   5301     /**
   5302      * Cause an invalidate to happen on a subsequent cycle through the event
   5303      * loop. Waits for the specified amount of time.
   5304      *
   5305      * @param delayMilliseconds the duration in milliseconds to delay the
   5306      *         invalidation by
   5307      */
   5308     public void postInvalidateDelayed(long delayMilliseconds) {
   5309         // We try only with the AttachInfo because there's no point in invalidating
   5310         // if we are not attached to our window
   5311         if (mAttachInfo != null) {
   5312             Message msg = Message.obtain();
   5313             msg.what = AttachInfo.INVALIDATE_MSG;
   5314             msg.obj = this;
   5315             mAttachInfo.mHandler.sendMessageDelayed(msg, delayMilliseconds);
   5316         }
   5317     }
   5318 
   5319     /**
   5320      * Cause an invalidate of the specified area to happen on a subsequent cycle
   5321      * through the event loop. Waits for the specified amount of time.
   5322      *
   5323      * @param delayMilliseconds the duration in milliseconds to delay the
   5324      *         invalidation by
   5325      * @param left The left coordinate of the rectangle to invalidate.
   5326      * @param top The top coordinate of the rectangle to invalidate.
   5327      * @param right The right coordinate of the rectangle to invalidate.
   5328      * @param bottom The bottom coordinate of the rectangle to invalidate.
   5329      */
   5330     public void postInvalidateDelayed(long delayMilliseconds, int left, int top,
   5331             int right, int bottom) {
   5332 
   5333         // We try only with the AttachInfo because there's no point in invalidating
   5334         // if we are not attached to our window
   5335         if (mAttachInfo != null) {
   5336             final AttachInfo.InvalidateInfo info = AttachInfo.InvalidateInfo.acquire();
   5337             info.target = this;
   5338             info.left = left;
   5339             info.top = top;
   5340             info.right = right;
   5341             info.bottom = bottom;
   5342 
   5343             final Message msg = Message.obtain();
   5344             msg.what = AttachInfo.INVALIDATE_RECT_MSG;
   5345             msg.obj = info;
   5346             mAttachInfo.mHandler.sendMessageDelayed(msg, delayMilliseconds);
   5347         }
   5348     }
   5349 
   5350     /**
   5351      * Called by a parent to request that a child update its values for mScrollX
   5352      * and mScrollY if necessary. This will typically be done if the child is
   5353      * animating a scroll using a {@link android.widget.Scroller Scroller}
   5354      * object.
   5355      */
   5356     public void computeScroll() {
   5357     }
   5358 
   5359     /**
   5360      * <p>Indicate whether the horizontal edges are faded when the view is
   5361      * scrolled horizontally.</p>
   5362      *
   5363      * @return true if the horizontal edges should are faded on scroll, false
   5364      *         otherwise
   5365      *
   5366      * @see #setHorizontalFadingEdgeEnabled(boolean)
   5367      * @attr ref android.R.styleable#View_fadingEdge
   5368      */
   5369     public boolean isHorizontalFadingEdgeEnabled() {
   5370         return (mViewFlags & FADING_EDGE_HORIZONTAL) == FADING_EDGE_HORIZONTAL;
   5371     }
   5372 
   5373     /**
   5374      * <p>Define whether the horizontal edges should be faded when this view
   5375      * is scrolled horizontally.</p>
   5376      *
   5377      * @param horizontalFadingEdgeEnabled true if the horizontal edges should
   5378      *                                    be faded when the view is scrolled
   5379      *                                    horizontally
   5380      *
   5381      * @see #isHorizontalFadingEdgeEnabled()
   5382      * @attr ref android.R.styleable#View_fadingEdge
   5383      */
   5384     public void setHorizontalFadingEdgeEnabled(boolean horizontalFadingEdgeEnabled) {
   5385         if (isHorizontalFadingEdgeEnabled() != horizontalFadingEdgeEnabled) {
   5386             if (horizontalFadingEdgeEnabled) {
   5387                 initScrollCache();
   5388             }
   5389 
   5390             mViewFlags ^= FADING_EDGE_HORIZONTAL;
   5391         }
   5392     }
   5393 
   5394     /**
   5395      * <p>Indicate whether the vertical edges are faded when the view is
   5396      * scrolled horizontally.</p>
   5397      *
   5398      * @return true if the vertical edges should are faded on scroll, false
   5399      *         otherwise
   5400      *
   5401      * @see #setVerticalFadingEdgeEnabled(boolean)
   5402      * @attr ref android.R.styleable#View_fadingEdge
   5403      */
   5404     public boolean isVerticalFadingEdgeEnabled() {
   5405         return (mViewFlags & FADING_EDGE_VERTICAL) == FADING_EDGE_VERTICAL;
   5406     }
   5407 
   5408     /**
   5409      * <p>Define whether the vertical edges should be faded when this view
   5410      * is scrolled vertically.</p>
   5411      *
   5412      * @param verticalFadingEdgeEnabled true if the vertical edges should
   5413      *                                  be faded when the view is scrolled
   5414      *                                  vertically
   5415      *
   5416      * @see #isVerticalFadingEdgeEnabled()
   5417      * @attr ref android.R.styleable#View_fadingEdge
   5418      */
   5419     public void setVerticalFadingEdgeEnabled(boolean verticalFadingEdgeEnabled) {
   5420         if (isVerticalFadingEdgeEnabled() != verticalFadingEdgeEnabled) {
   5421             if (verticalFadingEdgeEnabled) {
   5422                 initScrollCache();
   5423             }
   5424 
   5425             mViewFlags ^= FADING_EDGE_VERTICAL;
   5426         }
   5427     }
   5428 
   5429     /**
   5430      * Returns the strength, or intensity, of the top faded edge. The strength is
   5431      * a value between 0.0 (no fade) and 1.0 (full fade). The default implementation
   5432      * returns 0.0 or 1.0 but no value in between.
   5433      *
   5434      * Subclasses should override this method to provide a smoother fade transition
   5435      * when scrolling occurs.
   5436      *
   5437      * @return the intensity of the top fade as a float between 0.0f and 1.0f
   5438      */
   5439     protected float getTopFadingEdgeStrength() {
   5440         return computeVerticalScrollOffset() > 0 ? 1.0f : 0.0f;
   5441     }
   5442 
   5443     /**
   5444      * Returns the strength, or intensity, of the bottom faded edge. The strength is
   5445      * a value between 0.0 (no fade) and 1.0 (full fade). The default implementation
   5446      * returns 0.0 or 1.0 but no value in between.
   5447      *
   5448      * Subclasses should override this method to provide a smoother fade transition
   5449      * when scrolling occurs.
   5450      *
   5451      * @return the intensity of the bottom fade as a float between 0.0f and 1.0f
   5452      */
   5453     protected float getBottomFadingEdgeStrength() {
   5454         return computeVerticalScrollOffset() + computeVerticalScrollExtent() <
   5455                 computeVerticalScrollRange() ? 1.0f : 0.0f;
   5456     }
   5457 
   5458     /**
   5459      * Returns the strength, or intensity, of the left faded edge. The strength is
   5460      * a value between 0.0 (no fade) and 1.0 (full fade). The default implementation
   5461      * returns 0.0 or 1.0 but no value in between.
   5462      *
   5463      * Subclasses should override this method to provide a smoother fade transition
   5464      * when scrolling occurs.
   5465      *
   5466      * @return the intensity of the left fade as a float between 0.0f and 1.0f
   5467      */
   5468     protected float getLeftFadingEdgeStrength() {
   5469         return computeHorizontalScrollOffset() > 0 ? 1.0f : 0.0f;
   5470     }
   5471 
   5472     /**
   5473      * Returns the strength, or intensity, of the right faded edge. The strength is
   5474      * a value between 0.0 (no fade) and 1.0 (full fade). The default implementation
   5475      * returns 0.0 or 1.0 but no value in between.
   5476      *
   5477      * Subclasses should override this method to provide a smoother fade transition
   5478      * when scrolling occurs.
   5479      *
   5480      * @return the intensity of the right fade as a float between 0.0f and 1.0f
   5481      */
   5482     protected float getRightFadingEdgeStrength() {
   5483         return computeHorizontalScrollOffset() + computeHorizontalScrollExtent() <
   5484                 computeHorizontalScrollRange() ? 1.0f : 0.0f;
   5485     }
   5486 
   5487     /**
   5488      * <p>Indicate whether the horizontal scrollbar should be drawn or not. The
   5489      * scrollbar is not drawn by default.</p>
   5490      *
   5491      * @return true if the horizontal scrollbar should be painted, false
   5492      *         otherwise
   5493      *
   5494      * @see #setHorizontalScrollBarEnabled(boolean)
   5495      */
   5496     public boolean isHorizontalScrollBarEnabled() {
   5497         return (mViewFlags & SCROLLBARS_HORIZONTAL) == SCROLLBARS_HORIZONTAL;
   5498     }
   5499 
   5500     /**
   5501      * <p>Define whether the horizontal scrollbar should be drawn or not. The
   5502      * scrollbar is not drawn by default.</p>
   5503      *
   5504      * @param horizontalScrollBarEnabled true if the horizontal scrollbar should
   5505      *                                   be painted
   5506      *
   5507      * @see #isHorizontalScrollBarEnabled()
   5508      */
   5509     public void setHorizontalScrollBarEnabled(boolean horizontalScrollBarEnabled) {
   5510         if (isHorizontalScrollBarEnabled() != horizontalScrollBarEnabled) {
   5511             mViewFlags ^= SCROLLBARS_HORIZONTAL;
   5512             computeOpaqueFlags();
   5513             recomputePadding();
   5514         }
   5515     }
   5516 
   5517     /**
   5518      * <p>Indicate whether the vertical scrollbar should be drawn or not. The
   5519      * scrollbar is not drawn by default.</p>
   5520      *
   5521      * @return true if the vertical scrollbar should be painted, false
   5522      *         otherwise
   5523      *
   5524      * @see #setVerticalScrollBarEnabled(boolean)
   5525      */
   5526     public boolean isVerticalScrollBarEnabled() {
   5527         return (mViewFlags & SCROLLBARS_VERTICAL) == SCROLLBARS_VERTICAL;
   5528     }
   5529 
   5530     /**
   5531      * <p>Define whether the vertical scrollbar should be drawn or not. The
   5532      * scrollbar is not drawn by default.</p>
   5533      *
   5534      * @param verticalScrollBarEnabled true if the vertical scrollbar should
   5535      *                                 be painted
   5536      *
   5537      * @see #isVerticalScrollBarEnabled()
   5538      */
   5539     public void setVerticalScrollBarEnabled(boolean verticalScrollBarEnabled) {
   5540         if (isVerticalScrollBarEnabled() != verticalScrollBarEnabled) {
   5541             mViewFlags ^= SCROLLBARS_VERTICAL;
   5542             computeOpaqueFlags();
   5543             recomputePadding();
   5544         }
   5545     }
   5546 
   5547     private void recomputePadding() {
   5548         setPadding(mPaddingLeft, mPaddingTop, mUserPaddingRight, mUserPaddingBottom);
   5549     }
   5550 
   5551     /**
   5552      * Define whether scrollbars will fade when the view is not scrolling.
   5553      *
   5554      * @param fadeScrollbars wheter to enable fading
   5555      *
   5556      */
   5557     public void setScrollbarFadingEnabled(boolean fadeScrollbars) {
   5558         initScrollCache();
   5559         final ScrollabilityCache scrollabilityCache = mScrollCache;
   5560         scrollabilityCache.fadeScrollBars = fadeScrollbars;
   5561         if (fadeScrollbars) {
   5562             scrollabilityCache.state = ScrollabilityCache.OFF;
   5563         } else {
   5564             scrollabilityCache.state = ScrollabilityCache.ON;
   5565         }
   5566     }
   5567 
   5568     /**
   5569      *
   5570      * Returns true if scrollbars will fade when this view is not scrolling
   5571      *
   5572      * @return true if scrollbar fading is enabled
   5573      */
   5574     public boolean isScrollbarFadingEnabled() {
   5575         return mScrollCache != null && mScrollCache.fadeScrollBars;
   5576     }
   5577 
   5578     /**
   5579      * <p>Specify the style of the scrollbars. The scrollbars can be overlaid or
   5580      * inset. When inset, they add to the padding of the view. And the scrollbars
   5581      * can be drawn inside the padding area or on the edge of the view. For example,
   5582      * if a view has a background drawable and you want to draw the scrollbars
   5583      * inside the padding specified by the drawable, you can use
   5584      * SCROLLBARS_INSIDE_OVERLAY or SCROLLBARS_INSIDE_INSET. If you want them to
   5585      * appear at the edge of the view, ignoring the padding, then you can use
   5586      * SCROLLBARS_OUTSIDE_OVERLAY or SCROLLBARS_OUTSIDE_INSET.</p>
   5587      * @param style the style of the scrollbars. Should be one of
   5588      * SCROLLBARS_INSIDE_OVERLAY, SCROLLBARS_INSIDE_INSET,
   5589      * SCROLLBARS_OUTSIDE_OVERLAY or SCROLLBARS_OUTSIDE_INSET.
   5590      * @see #SCROLLBARS_INSIDE_OVERLAY
   5591      * @see #SCROLLBARS_INSIDE_INSET
   5592      * @see #SCROLLBARS_OUTSIDE_OVERLAY
   5593      * @see #SCROLLBARS_OUTSIDE_INSET
   5594      */
   5595     public void setScrollBarStyle(int style) {
   5596         if (style != (mViewFlags & SCROLLBARS_STYLE_MASK)) {
   5597             mViewFlags = (mViewFlags & ~SCROLLBARS_STYLE_MASK) | (style & SCROLLBARS_STYLE_MASK);
   5598             computeOpaqueFlags();
   5599             recomputePadding();
   5600         }
   5601     }
   5602 
   5603     /**
   5604      * <p>Returns the current scrollbar style.</p>
   5605      * @return the current scrollbar style
   5606      * @see #SCROLLBARS_INSIDE_OVERLAY
   5607      * @see #SCROLLBARS_INSIDE_INSET
   5608      * @see #SCROLLBARS_OUTSIDE_OVERLAY
   5609      * @see #SCROLLBARS_OUTSIDE_INSET
   5610      */
   5611     public int getScrollBarStyle() {
   5612         return mViewFlags & SCROLLBARS_STYLE_MASK;
   5613     }
   5614 
   5615     /**
   5616      * <p>Compute the horizontal range that the horizontal scrollbar
   5617      * represents.</p>
   5618      *
   5619      * <p>The range is expressed in arbitrary units that must be the same as the
   5620      * units used by {@link #computeHorizontalScrollExtent()} and
   5621      * {@link #computeHorizontalScrollOffset()}.</p>
   5622      *
   5623      * <p>The default range is the drawing width of this view.</p>
   5624      *
   5625      * @return the total horizontal range represented by the horizontal
   5626      *         scrollbar
   5627      *
   5628      * @see #computeHorizontalScrollExtent()
   5629      * @see #computeHorizontalScrollOffset()
   5630      * @see android.widget.ScrollBarDrawable
   5631      */
   5632     protected int computeHorizontalScrollRange() {
   5633         return getWidth();
   5634     }
   5635 
   5636     /**
   5637      * <p>Compute the horizontal offset of the horizontal scrollbar's thumb
   5638      * within the horizontal range. This value is used to compute the position
   5639      * of the thumb within the scrollbar's track.</p>
   5640      *
   5641      * <p>The range is expressed in arbitrary units that must be the same as the
   5642      * units used by {@link #computeHorizontalScrollRange()} and
   5643      * {@link #computeHorizontalScrollExtent()}.</p>
   5644      *
   5645      * <p>The default offset is the scroll offset of this view.</p>
   5646      *
   5647      * @return the horizontal offset of the scrollbar's thumb
   5648      *
   5649      * @see #computeHorizontalScrollRange()
   5650      * @see #computeHorizontalScrollExtent()
   5651      * @see android.widget.ScrollBarDrawable
   5652      */
   5653     protected int computeHorizontalScrollOffset() {
   5654         return mScrollX;
   5655     }
   5656 
   5657     /**
   5658      * <p>Compute the horizontal extent of the horizontal scrollbar's thumb
   5659      * within the horizontal range. This value is used to compute the length
   5660      * of the thumb within the scrollbar's track.</p>
   5661      *
   5662      * <p>The range is expressed in arbitrary units that must be the same as the
   5663      * units used by {@link #computeHorizontalScrollRange()} and
   5664      * {@link #computeHorizontalScrollOffset()}.</p>
   5665      *
   5666      * <p>The default extent is the drawing width of this view.</p>
   5667      *
   5668      * @return the horizontal extent of the scrollbar's thumb
   5669      *
   5670      * @see #computeHorizontalScrollRange()
   5671      * @see #computeHorizontalScrollOffset()
   5672      * @see android.widget.ScrollBarDrawable
   5673      */
   5674     protected int computeHorizontalScrollExtent() {
   5675         return getWidth();
   5676     }
   5677 
   5678     /**
   5679      * <p>Compute the vertical range that the vertical scrollbar represents.</p>
   5680      *
   5681      * <p>The range is expressed in arbitrary units that must be the same as the
   5682      * units used by {@link #computeVerticalScrollExtent()} and
   5683      * {@link #computeVerticalScrollOffset()}.</p>
   5684      *
   5685      * @return the total vertical range represented by the vertical scrollbar
   5686      *
   5687      * <p>The default range is the drawing height of this view.</p>
   5688      *
   5689      * @see #computeVerticalScrollExtent()
   5690      * @see #computeVerticalScrollOffset()
   5691      * @see android.widget.ScrollBarDrawable
   5692      */
   5693     protected int computeVerticalScrollRange() {
   5694         return getHeight();
   5695     }
   5696 
   5697     /**
   5698      * <p>Compute the vertical offset of the vertical scrollbar's thumb
   5699      * within the horizontal range. This value is used to compute the position
   5700      * of the thumb within the scrollbar's track.</p>
   5701      *
   5702      * <p>The range is expressed in arbitrary units that must be the same as the
   5703      * units used by {@link #computeVerticalScrollRange()} and
   5704      * {@link #computeVerticalScrollExtent()}.</p>
   5705      *
   5706      * <p>The default offset is the scroll offset of this view.</p>
   5707      *
   5708      * @return the vertical offset of the scrollbar's thumb
   5709      *
   5710      * @see #computeVerticalScrollRange()
   5711      * @see #computeVerticalScrollExtent()
   5712      * @see android.widget.ScrollBarDrawable
   5713      */
   5714     protected int computeVerticalScrollOffset() {
   5715         return mScrollY;
   5716     }
   5717 
   5718     /**
   5719      * <p>Compute the vertical extent of the horizontal scrollbar's thumb
   5720      * within the vertical range. This value is used to compute the length
   5721      * of the thumb within the scrollbar's track.</p>
   5722      *
   5723      * <p>The range is expressed in arbitrary units that must be the same as the
   5724      * units used by {@link #computeVerticalScrollRange()} and
   5725      * {@link #computeVerticalScrollOffset()}.</p>
   5726      *
   5727      * <p>The default extent is the drawing height of this view.</p>
   5728      *
   5729      * @return the vertical extent of the scrollbar's thumb
   5730      *
   5731      * @see #computeVerticalScrollRange()
   5732      * @see #computeVerticalScrollOffset()
   5733      * @see android.widget.ScrollBarDrawable
   5734      */
   5735     protected int computeVerticalScrollExtent() {
   5736         return getHeight();
   5737     }
   5738 
   5739     /**
   5740      * <p>Request the drawing of the horizontal and the vertical scrollbar. The
   5741      * scrollbars are painted only if they have been awakened first.</p>
   5742      *
   5743      * @param canvas the canvas on which to draw the scrollbars
   5744      *
   5745      * @see #awakenScrollBars(int)
   5746      */
   5747     protected final void onDrawScrollBars(Canvas canvas) {
   5748         // scrollbars are drawn only when the animation is running
   5749         final ScrollabilityCache cache = mScrollCache;
   5750         if (cache != null) {
   5751 
   5752             int state = cache.state;
   5753 
   5754             if (state == ScrollabilityCache.OFF) {
   5755                 return;
   5756             }
   5757 
   5758             boolean invalidate = false;
   5759 
   5760             if (state == ScrollabilityCache.FADING) {
   5761                 // We're fading -- get our fade interpolation
   5762                 if (cache.interpolatorValues == null) {
   5763                     cache.interpolatorValues = new float[1];
   5764                 }
   5765 
   5766                 float[] values = cache.interpolatorValues;
   5767 
   5768                 // Stops the animation if we're done
   5769                 if (cache.scrollBarInterpolator.timeToValues(values) ==
   5770                         Interpolator.Result.FREEZE_END) {
   5771                     cache.state = ScrollabilityCache.OFF;
   5772                 } else {
   5773                     cache.scrollBar.setAlpha(Math.round(values[0]));
   5774                 }
   5775 
   5776                 // This will make the scroll bars inval themselves after
   5777                 // drawing. We only want this when we're fading so that
   5778                 // we prevent excessive redraws
   5779                 invalidate = true;
   5780             } else {
   5781                 // We're just on -- but we may have been fading before so
   5782                 // reset alpha
   5783                 cache.scrollBar.setAlpha(255);
   5784             }
   5785 
   5786 
   5787             final int viewFlags = mViewFlags;
   5788 
   5789             final boolean drawHorizontalScrollBar =
   5790                 (viewFlags & SCROLLBARS_HORIZONTAL) == SCROLLBARS_HORIZONTAL;
   5791             final boolean drawVerticalScrollBar =
   5792                 (viewFlags & SCROLLBARS_VERTICAL) == SCROLLBARS_VERTICAL
   5793                 && !isVerticalScrollBarHidden();
   5794 
   5795             if (drawVerticalScrollBar || drawHorizontalScrollBar) {
   5796                 final int width = mRight - mLeft;
   5797                 final int height = mBottom - mTop;
   5798 
   5799                 final ScrollBarDrawable scrollBar = cache.scrollBar;
   5800                 int size = scrollBar.getSize(false);
   5801                 if (size <= 0) {
   5802                     size = cache.scrollBarSize;
   5803                 }
   5804 
   5805                 final int scrollX = mScrollX;
   5806                 final int scrollY = mScrollY;
   5807                 final int inside = (viewFlags & SCROLLBARS_OUTSIDE_MASK) == 0 ? ~0 : 0;
   5808 
   5809                 int left, top, right, bottom;
   5810 
   5811                 if (drawHorizontalScrollBar) {
   5812                     scrollBar.setParameters(computeHorizontalScrollRange(),
   5813                                             computeHorizontalScrollOffset(),
   5814                                             computeHorizontalScrollExtent(), false);
   5815                     final int verticalScrollBarGap = drawVerticalScrollBar ?
   5816                             getVerticalScrollbarWidth() : 0;
   5817                     top = scrollY + height - size - (mUserPaddingBottom & inside);
   5818                     left = scrollX + (mPaddingLeft & inside);
   5819                     right = scrollX + width - (mUserPaddingRight & inside) - verticalScrollBarGap;
   5820                     bottom = top + size;
   5821                     onDrawHorizontalScrollBar(canvas, scrollBar, left, top, right, bottom);
   5822                     if (invalidate) {
   5823                         invalidate(left, top, right, bottom);
   5824                     }
   5825                 }
   5826 
   5827                 if (drawVerticalScrollBar) {
   5828                     scrollBar.setParameters(computeVerticalScrollRange(),
   5829                                             computeVerticalScrollOffset(),
   5830                                             computeVerticalScrollExtent(), true);
   5831                     // TODO: Deal with RTL languages to position scrollbar on left
   5832                     left = scrollX + width - size - (mUserPaddingRight & inside);
   5833                     top = scrollY + (mPaddingTop & inside);
   5834                     right = left + size;
   5835                     bottom = scrollY + height - (mUserPaddingBottom & inside);
   5836                     onDrawVerticalScrollBar(canvas, scrollBar, left, top, right, bottom);
   5837                     if (invalidate) {
   5838                         invalidate(left, top, right, bottom);
   5839                     }
   5840                 }
   5841             }
   5842         }
   5843     }
   5844 
   5845     /**
   5846      * Override this if the vertical scrollbar needs to be hidden in a subclass, like when
   5847      * FastScroller is visible.
   5848      * @return whether to temporarily hide the vertical scrollbar
   5849      * @hide
   5850      */
   5851     protected boolean isVerticalScrollBarHidden() {
   5852         return false;
   5853     }
   5854 
   5855     /**
   5856      * <p>Draw the horizontal scrollbar if
   5857      * {@link #isHorizontalScrollBarEnabled()} returns true.</p>
   5858      *
   5859      * @param canvas the canvas on which to draw the scrollbar
   5860      * @param scrollBar the scrollbar's drawable
   5861      *
   5862      * @see #isHorizontalScrollBarEnabled()
   5863      * @see #computeHorizontalScrollRange()
   5864      * @see #computeHorizontalScrollExtent()
   5865      * @see #computeHorizontalScrollOffset()
   5866      * @see android.widget.ScrollBarDrawable
   5867      * @hide
   5868      */
   5869     protected void onDrawHorizontalScrollBar(Canvas canvas,
   5870                                              Drawable scrollBar,
   5871                                              int l, int t, int r, int b) {
   5872         scrollBar.setBounds(l, t, r, b);
   5873         scrollBar.draw(canvas);
   5874     }
   5875 
   5876     /**
   5877      * <p>Draw the vertical scrollbar if {@link #isVerticalScrollBarEnabled()}
   5878      * returns true.</p>
   5879      *
   5880      * @param canvas the canvas on which to draw the scrollbar
   5881      * @param scrollBar the scrollbar's drawable
   5882      *
   5883      * @see #isVerticalScrollBarEnabled()
   5884      * @see #computeVerticalScrollRange()
   5885      * @see #computeVerticalScrollExtent()
   5886      * @see #computeVerticalScrollOffset()
   5887      * @see android.widget.ScrollBarDrawable
   5888      * @hide
   5889      */
   5890     protected void onDrawVerticalScrollBar(Canvas canvas,
   5891                                            Drawable scrollBar,
   5892                                            int l, int t, int r, int b) {
   5893         scrollBar.setBounds(l, t, r, b);
   5894         scrollBar.draw(canvas);
   5895     }
   5896 
   5897     /**
   5898      * Implement this to do your drawing.
   5899      *
   5900      * @param canvas the canvas on which the background will be drawn
   5901      */
   5902     protected void onDraw(Canvas canvas) {
   5903     }
   5904 
   5905     /*
   5906      * Caller is responsible for calling requestLayout if necessary.
   5907      * (This allows addViewInLayout to not request a new layout.)
   5908      */
   5909     void assignParent(ViewParent parent) {
   5910         if (mParent == null) {
   5911             mParent = parent;
   5912         } else if (parent == null) {
   5913             mParent = null;
   5914         } else {
   5915             throw new RuntimeException("view " + this + " being added, but"
   5916                     + " it already has a parent");
   5917         }
   5918     }
   5919 
   5920     /**
   5921      * This is called when the view is attached to a window.  At this point it
   5922      * has a Surface and will start drawing.  Note that this function is
   5923      * guaranteed to be called before {@link #onDraw}, however it may be called
   5924      * any time before the first onDraw -- including before or after
   5925      * {@link #onMeasure}.
   5926      *
   5927      * @see #onDetachedFromWindow()
   5928      */
   5929     protected void onAttachedToWindow() {
   5930         if ((mPrivateFlags & REQUEST_TRANSPARENT_REGIONS) != 0) {
   5931             mParent.requestTransparentRegion(this);
   5932         }
   5933         if ((mPrivateFlags & AWAKEN_SCROLL_BARS_ON_ATTACH) != 0) {
   5934             initialAwakenScrollBars();
   5935             mPrivateFlags &= ~AWAKEN_SCROLL_BARS_ON_ATTACH;
   5936         }
   5937     }
   5938 
   5939     /**
   5940      * This is called when the view is detached from a window.  At this point it
   5941      * no longer has a surface for drawing.
   5942      *
   5943      * @see #onAttachedToWindow()
   5944      */
   5945     protected void onDetachedFromWindow() {
   5946         mPrivateFlags &= ~CANCEL_NEXT_UP_EVENT;
   5947         removeUnsetPressCallback();
   5948         removeLongPressCallback();
   5949         destroyDrawingCache();
   5950     }
   5951 
   5952     /**
   5953      * @return The number of times this view has been attached to a window
   5954      */
   5955     protected int getWindowAttachCount() {
   5956         return mWindowAttachCount;
   5957     }
   5958 
   5959     /**
   5960      * Retrieve a unique token identifying the window this view is attached to.
   5961      * @return Return the window's token for use in
   5962      * {@link WindowManager.LayoutParams#token WindowManager.LayoutParams.token}.
   5963      */
   5964     public IBinder getWindowToken() {
   5965         return mAttachInfo != null ? mAttachInfo.mWindowToken : null;
   5966     }
   5967 
   5968     /**
   5969      * Retrieve a unique token identifying the top-level "real" window of
   5970      * the window that this view is attached to.  That is, this is like
   5971      * {@link #getWindowToken}, except if the window this view in is a panel
   5972      * window (attached to another containing window), then the token of
   5973      * the containing window is returned instead.
   5974      *
   5975      * @return Returns the associated window token, either
   5976      * {@link #getWindowToken()} or the containing window's token.
   5977      */
   5978     public IBinder getApplicationWindowToken() {
   5979         AttachInfo ai = mAttachInfo;
   5980         if (ai != null) {
   5981             IBinder appWindowToken = ai.mPanelParentWindowToken;
   5982             if (appWindowToken == null) {
   5983                 appWindowToken = ai.mWindowToken;
   5984             }
   5985             return appWindowToken;
   5986         }
   5987         return null;
   5988     }
   5989 
   5990     /**
   5991      * Retrieve private session object this view hierarchy is using to
   5992      * communicate with the window manager.
   5993      * @return the session object to communicate with the window manager
   5994      */
   5995     /*package*/ IWindowSession getWindowSession() {
   5996         return mAttachInfo != null ? mAttachInfo.mSession : null;
   5997     }
   5998 
   5999     /**
   6000      * @param info the {@link android.view.View.AttachInfo} to associated with
   6001      *        this view
   6002      */
   6003     void dispatchAttachedToWindow(AttachInfo info, int visibility) {
   6004         //System.out.println("Attached! " + this);
   6005         mAttachInfo = info;
   6006         mWindowAttachCount++;
   6007         if (mFloatingTreeObserver != null) {
   6008             info.mTreeObserver.merge(mFloatingTreeObserver);
   6009             mFloatingTreeObserver = null;
   6010         }
   6011         if ((mPrivateFlags&SCROLL_CONTAINER) != 0) {
   6012             mAttachInfo.mScrollContainers.add(this);
   6013             mPrivateFlags |= SCROLL_CONTAINER_ADDED;
   6014         }
   6015         performCollectViewAttributes(visibility);
   6016         onAttachedToWindow();
   6017         int vis = info.mWindowVisibility;
   6018         if (vis != GONE) {
   6019             onWindowVisibilityChanged(vis);
   6020         }
   6021     }
   6022 
   6023     void dispatchDetachedFromWindow() {
   6024         //System.out.println("Detached! " + this);
   6025         AttachInfo info = mAttachInfo;
   6026         if (info != null) {
   6027             int vis = info.mWindowVisibility;
   6028             if (vis != GONE) {
   6029                 onWindowVisibilityChanged(GONE);
   6030             }
   6031         }
   6032 
   6033         onDetachedFromWindow();
   6034         if ((mPrivateFlags&SCROLL_CONTAINER_ADDED) != 0) {
   6035             mAttachInfo.mScrollContainers.remove(this);
   6036             mPrivateFlags &= ~SCROLL_CONTAINER_ADDED;
   6037         }
   6038         mAttachInfo = null;
   6039     }
   6040 
   6041     /**
   6042      * Store this view hierarchy's frozen state into the given container.
   6043      *
   6044      * @param container The SparseArray in which to save the view's state.
   6045      *
   6046      * @see #restoreHierarchyState
   6047      * @see #dispatchSaveInstanceState
   6048      * @see #onSaveInstanceState
   6049      */
   6050     public void saveHierarchyState(SparseArray<Parcelable> container) {
   6051         dispatchSaveInstanceState(container);
   6052     }
   6053 
   6054     /**
   6055      * Called by {@link #saveHierarchyState} to store the state for this view and its children.
   6056      * May be overridden to modify how freezing happens to a view's children; for example, some
   6057      * views may want to not store state for their children.
   6058      *
   6059      * @param container The SparseArray in which to save the view's state.
   6060      *
   6061      * @see #dispatchRestoreInstanceState
   6062      * @see #saveHierarchyState
   6063      * @see #onSaveInstanceState
   6064      */
   6065     protected void dispatchSaveInstanceState(SparseArray<Parcelable> container) {
   6066         if (mID != NO_ID && (mViewFlags & SAVE_DISABLED_MASK) == 0) {
   6067             mPrivateFlags &= ~SAVE_STATE_CALLED;
   6068             Parcelable state = onSaveInstanceState();
   6069             if ((mPrivateFlags & SAVE_STATE_CALLED) == 0) {
   6070                 throw new IllegalStateException(
   6071                         "Derived class did not call super.onSaveInstanceState()");
   6072             }
   6073             if (state != null) {
   6074                 // Log.i("View", "Freezing #" + Integer.toHexString(mID)
   6075                 // + ": " + state);
   6076                 container.put(mID, state);
   6077             }
   6078         }
   6079     }
   6080 
   6081     /**
   6082      * Hook allowing a view to generate a representation of its internal state
   6083      * that can later be used to create a new instance with that same state.
   6084      * This state should only contain information that is not persistent or can
   6085      * not be reconstructed later. For example, you will never store your
   6086      * current position on screen because that will be computed again when a
   6087      * new instance of the view is placed in its view hierarchy.
   6088      * <p>
   6089      * Some examples of things you may store here: the current cursor position
   6090      * in a text view (but usually not the text itself since that is stored in a
   6091      * content provider or other persistent storage), the currently selected
   6092      * item in a list view.
   6093      *
   6094      * @return Returns a Parcelable object containing the view's current dynamic
   6095      *         state, or null if there is nothing interesting to save. The
   6096      *         default implementation returns null.
   6097      * @see #onRestoreInstanceState
   6098      * @see #saveHierarchyState
   6099      * @see #dispatchSaveInstanceState
   6100      * @see #setSaveEnabled(boolean)
   6101      */
   6102     protected Parcelable onSaveInstanceState() {
   6103         mPrivateFlags |= SAVE_STATE_CALLED;
   6104         return BaseSavedState.EMPTY_STATE;
   6105     }
   6106 
   6107     /**
   6108      * Restore this view hierarchy's frozen state from the given container.
   6109      *
   6110      * @param container The SparseArray which holds previously frozen states.
   6111      *
   6112      * @see #saveHierarchyState
   6113      * @see #dispatchRestoreInstanceState
   6114      * @see #onRestoreInstanceState
   6115      */
   6116     public void restoreHierarchyState(SparseArray<Parcelable> container) {
   6117         dispatchRestoreInstanceState(container);
   6118     }
   6119 
   6120     /**
   6121      * Called by {@link #restoreHierarchyState} to retrieve the state for this view and its
   6122      * children. May be overridden to modify how restoreing happens to a view's children; for
   6123      * example, some views may want to not store state for their children.
   6124      *
   6125      * @param container The SparseArray which holds previously saved state.
   6126      *
   6127      * @see #dispatchSaveInstanceState
   6128      * @see #restoreHierarchyState
   6129      * @see #onRestoreInstanceState
   6130      */
   6131     protected void dispatchRestoreInstanceState(SparseArray<Parcelable> container) {
   6132         if (mID != NO_ID) {
   6133             Parcelable state = container.get(mID);
   6134             if (state != null) {
   6135                 // Log.i("View", "Restoreing #" + Integer.toHexString(mID)
   6136                 // + ": " + state);
   6137                 mPrivateFlags &= ~SAVE_STATE_CALLED;
   6138                 onRestoreInstanceState(state);
   6139                 if ((mPrivateFlags & SAVE_STATE_CALLED) == 0) {
   6140                     throw new IllegalStateException(
   6141                             "Derived class did not call super.onRestoreInstanceState()");
   6142                 }
   6143             }
   6144         }
   6145     }
   6146 
   6147     /**
   6148      * Hook allowing a view to re-apply a representation of its internal state that had previously
   6149      * been generated by {@link #onSaveInstanceState}. This function will never be called with a
   6150      * null state.
   6151      *
   6152      * @param state The frozen state that had previously been returned by
   6153      *        {@link #onSaveInstanceState}.
   6154      *
   6155      * @see #onSaveInstanceState
   6156      * @see #restoreHierarchyState
   6157      * @see #dispatchRestoreInstanceState
   6158      */
   6159     protected void onRestoreInstanceState(Parcelable state) {
   6160         mPrivateFlags |= SAVE_STATE_CALLED;
   6161         if (state != BaseSavedState.EMPTY_STATE && state != null) {
   6162             throw new IllegalArgumentException("Wrong state class, expecting View State but "
   6163                     + "received " + state.getClass().toString() + " instead. This usually happens "
   6164                     + "when two views of different type have the same id in the same hierarchy. "
   6165                     + "This view's id is " + ViewDebug.resolveId(mContext, getId()) + ". Make sure "
   6166                     + "other views do not use the same id.");
   6167         }
   6168     }
   6169 
   6170     /**
   6171      * <p>Return the time at which the drawing of the view hierarchy started.</p>
   6172      *
   6173      * @return the drawing start time in milliseconds
   6174      */
   6175     public long getDrawingTime() {
   6176         return mAttachInfo != null ? mAttachInfo.mDrawingTime : 0;
   6177     }
   6178 
   6179     /**
   6180      * <p>Enables or disables the duplication of the parent's state into this view. When
   6181      * duplication is enabled, this view gets its drawable state from its parent rather
   6182      * than from its own internal properties.</p>
   6183      *
   6184      * <p>Note: in the current implementation, setting this property to true after the
   6185      * view was added to a ViewGroup might have no effect at all. This property should
   6186      * always be used from XML or set to true before adding this view to a ViewGroup.</p>
   6187      *
   6188      * <p>Note: if this view's parent addStateFromChildren property is enabled and this
   6189      * property is enabled, an exception will be thrown.</p>
   6190      *
   6191      * @param enabled True to enable duplication of the parent's drawable state, false
   6192      *                to disable it.
   6193      *
   6194      * @see #getDrawableState()
   6195      * @see #isDuplicateParentStateEnabled()
   6196      */
   6197     public void setDuplicateParentStateEnabled(boolean enabled) {
   6198         setFlags(enabled ? DUPLICATE_PARENT_STATE : 0, DUPLICATE_PARENT_STATE);
   6199     }
   6200 
   6201     /**
   6202      * <p>Indicates whether this duplicates its drawable state from its parent.</p>
   6203      *
   6204      * @return True if this view's drawable state is duplicated from the parent,
   6205      *         false otherwise
   6206      *
   6207      * @see #getDrawableState()
   6208      * @see #setDuplicateParentStateEnabled(boolean)
   6209      */
   6210     public boolean isDuplicateParentStateEnabled() {
   6211         return (mViewFlags & DUPLICATE_PARENT_STATE) == DUPLICATE_PARENT_STATE;
   6212     }
   6213 
   6214     /**
   6215      * <p>Enables or disables the drawing cache. When the drawing cache is enabled, the next call
   6216      * to {@link #getDrawingCache()} or {@link #buildDrawingCache()} will draw the view in a
   6217      * bitmap. Calling {@link #draw(android.graphics.Canvas)} will not draw from the cache when
   6218      * the cache is enabled. To benefit from the cache, you must request the drawing cache by
   6219      * calling {@link #getDrawingCache()} and draw it on screen if the returned bitmap is not
   6220      * null.</p>
   6221      *
   6222      * @param enabled true to enable the drawing cache, false otherwise
   6223      *
   6224      * @see #isDrawingCacheEnabled()
   6225      * @see #getDrawingCache()
   6226      * @see #buildDrawingCache()
   6227      */
   6228     public void setDrawingCacheEnabled(boolean enabled) {
   6229         setFlags(enabled ? DRAWING_CACHE_ENABLED : 0, DRAWING_CACHE_ENABLED);
   6230     }
   6231 
   6232     /**
   6233      * <p>Indicates whether the drawing cache is enabled for this view.</p>
   6234      *
   6235      * @return true if the drawing cache is enabled
   6236      *
   6237      * @see #setDrawingCacheEnabled(boolean)
   6238      * @see #getDrawingCache()
   6239      */
   6240     @ViewDebug.ExportedProperty
   6241     public boolean isDrawingCacheEnabled() {
   6242         return (mViewFlags & DRAWING_CACHE_ENABLED) == DRAWING_CACHE_ENABLED;
   6243     }
   6244 
   6245     /**
   6246      * <p>Calling this method is equivalent to calling <code>getDrawingCache(false)</code>.</p>
   6247      *
   6248      * @return A non-scaled bitmap representing this view or null if cache is disabled.
   6249      *
   6250      * @see #getDrawingCache(boolean)
   6251      */
   6252     public Bitmap getDrawingCache() {
   6253         return getDrawingCache(false);
   6254     }
   6255 
   6256     /**
   6257      * <p>Returns the bitmap in which this view drawing is cached. The returned bitmap
   6258      * is null when caching is disabled. If caching is enabled and the cache is not ready,
   6259      * this method will create it. Calling {@link #draw(android.graphics.Canvas)} will not
   6260      * draw from the cache when the cache is enabled. To benefit from the cache, you must
   6261      * request the drawing cache by calling this method and draw it on screen if the
   6262      * returned bitmap is not null.</p>
   6263      *
   6264      * <p>Note about auto scaling in compatibility mode: When auto scaling is not enabled,
   6265      * this method will create a bitmap of the same size as this view. Because this bitmap
   6266      * will be drawn scaled by the parent ViewGroup, the result on screen might show
   6267      * scaling artifacts. To avoid such artifacts, you should call this method by setting
   6268      * the auto scaling to true. Doing so, however, will generate a bitmap of a different
   6269      * size than the view. This implies that your application must be able to handle this
   6270      * size.</p>
   6271      *
   6272      * @param autoScale Indicates whether the generated bitmap should be scaled based on
   6273      *        the current density of the screen when the application is in compatibility
   6274      *        mode.
   6275      *
   6276      * @return A bitmap representing this view or null if cache is disabled.
   6277      *
   6278      * @see #setDrawingCacheEnabled(boolean)
   6279      * @see #isDrawingCacheEnabled()
   6280      * @see #buildDrawingCache(boolean)
   6281      * @see #destroyDrawingCache()
   6282      */
   6283     public Bitmap getDrawingCache(boolean autoScale) {
   6284         if ((mViewFlags & WILL_NOT_CACHE_DRAWING) == WILL_NOT_CACHE_DRAWING) {
   6285             return null;
   6286         }
   6287         if ((mViewFlags & DRAWING_CACHE_ENABLED) == DRAWING_CACHE_ENABLED) {
   6288             buildDrawingCache(autoScale);
   6289         }
   6290         return autoScale ? (mDrawingCache == null ? null : mDrawingCache.get()) :
   6291                 (mUnscaledDrawingCache == null ? null : mUnscaledDrawingCache.get());
   6292     }
   6293 
   6294     /**
   6295      * <p>Frees the resources used by the drawing cache. If you call
   6296      * {@link #buildDrawingCache()} manually without calling
   6297      * {@link #setDrawingCacheEnabled(boolean) setDrawingCacheEnabled(true)}, you
   6298      * should cleanup the cache with this method afterwards.</p>
   6299      *
   6300      * @see #setDrawingCacheEnabled(boolean)
   6301      * @see #buildDrawingCache()
   6302      * @see #getDrawingCache()
   6303      */
   6304     public void destroyDrawingCache() {
   6305         if (mDrawingCache != null) {
   6306             final Bitmap bitmap = mDrawingCache.get();
   6307             if (bitmap != null) bitmap.recycle();
   6308             mDrawingCache = null;
   6309         }
   6310         if (mUnscaledDrawingCache != null) {
   6311             final Bitmap bitmap = mUnscaledDrawingCache.get();
   6312             if (bitmap != null) bitmap.recycle();
   6313             mUnscaledDrawingCache = null;
   6314         }
   6315     }
   6316 
   6317     /**
   6318      * Setting a solid background color for the drawing cache's bitmaps will improve
   6319      * perfromance and memory usage. Note, though that this should only be used if this
   6320      * view will always be drawn on top of a solid color.
   6321      *
   6322      * @param color The background color to use for the drawing cache's bitmap
   6323      *
   6324      * @see #setDrawingCacheEnabled(boolean)
   6325      * @see #buildDrawingCache()
   6326      * @see #getDrawingCache()
   6327      */
   6328     public void setDrawingCacheBackgroundColor(int color) {
   6329         if (color != mDrawingCacheBackgroundColor) {
   6330             mDrawingCacheBackgroundColor = color;
   6331             mPrivateFlags &= ~DRAWING_CACHE_VALID;
   6332         }
   6333     }
   6334 
   6335     /**
   6336      * @see #setDrawingCacheBackgroundColor(int)
   6337      *
   6338      * @return The background color to used for the drawing cache's bitmap
   6339      */
   6340     public int getDrawingCacheBackgroundColor() {
   6341         return mDrawingCacheBackgroundColor;
   6342     }
   6343 
   6344     /**
   6345      * <p>Calling this method is equivalent to calling <code>buildDrawingCache(false)</code>.</p>
   6346      *
   6347      * @see #buildDrawingCache(boolean)
   6348      */
   6349     public void buildDrawingCache() {
   6350         buildDrawingCache(false);
   6351     }
   6352 
   6353     /**
   6354      * <p>Forces the drawing cache to be built if the drawing cache is invalid.</p>
   6355      *
   6356      * <p>If you call {@link #buildDrawingCache()} manually without calling
   6357      * {@link #setDrawingCacheEnabled(boolean) setDrawingCacheEnabled(true)}, you
   6358      * should cleanup the cache by calling {@link #destroyDrawingCache()} afterwards.</p>
   6359      *
   6360      * <p>Note about auto scaling in compatibility mode: When auto scaling is not enabled,
   6361      * this method will create a bitmap of the same size as this view. Because this bitmap
   6362      * will be drawn scaled by the parent ViewGroup, the result on screen might show
   6363      * scaling artifacts. To avoid such artifacts, you should call this method by setting
   6364      * the auto scaling to true. Doing so, however, will generate a bitmap of a different
   6365      * size than the view. This implies that your application must be able to handle this
   6366      * size.</p>
   6367      *
   6368      * @see #getDrawingCache()
   6369      * @see #destroyDrawingCache()
   6370      */
   6371     public void buildDrawingCache(boolean autoScale) {
   6372         if ((mPrivateFlags & DRAWING_CACHE_VALID) == 0 || (autoScale ?
   6373                 (mDrawingCache == null || mDrawingCache.get() == null) :
   6374                 (mUnscaledDrawingCache == null || mUnscaledDrawingCache.get() == null))) {
   6375 
   6376             if (ViewDebug.TRACE_HIERARCHY) {
   6377                 ViewDebug.trace(this, ViewDebug.HierarchyTraceType.BUILD_CACHE);
   6378             }
   6379             if (Config.DEBUG && ViewDebug.profileDrawing) {
   6380                 EventLog.writeEvent(60002, hashCode());
   6381             }
   6382 
   6383             int width = mRight - mLeft;
   6384             int height = mBottom - mTop;
   6385 
   6386             final AttachInfo attachInfo = mAttachInfo;
   6387             final boolean scalingRequired = attachInfo != null && attachInfo.mScalingRequired;
   6388 
   6389             if (autoScale && scalingRequired) {
   6390                 width = (int) ((width * attachInfo.mApplicationScale) + 0.5f);
   6391                 height = (int) ((height * attachInfo.mApplicationScale) + 0.5f);
   6392             }
   6393 
   6394             final int drawingCacheBackgroundColor = mDrawingCacheBackgroundColor;
   6395             final boolean opaque = drawingCacheBackgroundColor != 0 || isOpaque();
   6396             final boolean translucentWindow = attachInfo != null && attachInfo.mTranslucentWindow;
   6397 
   6398             if (width <= 0 || height <= 0 ||
   6399                      // Projected bitmap size in bytes
   6400                     (width * height * (opaque && !translucentWindow ? 2 : 4) >
   6401                             ViewConfiguration.get(mContext).getScaledMaximumDrawingCacheSize())) {
   6402                 destroyDrawingCache();
   6403                 return;
   6404             }
   6405 
   6406             boolean clear = true;
   6407             Bitmap bitmap = autoScale ? (mDrawingCache == null ? null : mDrawingCache.get()) :
   6408                     (mUnscaledDrawingCache == null ? null : mUnscaledDrawingCache.get());
   6409 
   6410             if (bitmap == null || bitmap.getWidth() != width || bitmap.getHeight() != height) {
   6411                 Bitmap.Config quality;
   6412                 if (!opaque) {
   6413                     switch (mViewFlags & DRAWING_CACHE_QUALITY_MASK) {
   6414                         case DRAWING_CACHE_QUALITY_AUTO:
   6415                             quality = Bitmap.Config.ARGB_8888;
   6416                             break;
   6417                         case DRAWING_CACHE_QUALITY_LOW:
   6418                             quality = Bitmap.Config.ARGB_4444;
   6419                             break;
   6420                         case DRAWING_CACHE_QUALITY_HIGH:
   6421                             quality = Bitmap.Config.ARGB_8888;
   6422                             break;
   6423                         default:
   6424                             quality = Bitmap.Config.ARGB_8888;
   6425                             break;
   6426                     }
   6427                 } else {
   6428                     // Optimization for translucent windows
   6429                     // If the window is translucent, use a 32 bits bitmap to benefit from memcpy()
   6430                     quality = translucentWindow ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
   6431                 }
   6432 
   6433                 // Try to cleanup memory
   6434                 if (bitmap != null) bitmap.recycle();
   6435 
   6436                 try {
   6437                     bitmap = Bitmap.createBitmap(width, height, quality);
   6438                     bitmap.setDensity(getResources().getDisplayMetrics().densityDpi);
   6439                     if (autoScale) {
   6440                         mDrawingCache = new SoftReference<Bitmap>(bitmap);
   6441                     } else {
   6442                         mUnscaledDrawingCache = new SoftReference<Bitmap>(bitmap);
   6443                     }
   6444                     if (opaque && translucentWindow) bitmap.setHasAlpha(false);
   6445                 } catch (OutOfMemoryError e) {
   6446                     // If there is not enough memory to create the bitmap cache, just
   6447                     // ignore the issue as bitmap caches are not required to draw the
   6448                     // view hierarchy
   6449                     if (autoScale) {
   6450                         mDrawingCache = null;
   6451                     } else {
   6452                         mUnscaledDrawingCache = null;
   6453                     }
   6454                     return;
   6455                 }
   6456 
   6457                 clear = drawingCacheBackgroundColor != 0;
   6458             }
   6459 
   6460             Canvas canvas;
   6461             if (attachInfo != null) {
   6462                 canvas = attachInfo.mCanvas;
   6463                 if (canvas == null) {
   6464                     canvas = new Canvas();
   6465                 }
   6466                 canvas.setBitmap(bitmap);
   6467                 // Temporarily clobber the cached Canvas in case one of our children
   6468                 // is also using a drawing cache. Without this, the children would
   6469                 // steal the canvas by attaching their own bitmap to it and bad, bad
   6470                 // thing would happen (invisible views, corrupted drawings, etc.)
   6471                 attachInfo.mCanvas = null;
   6472             } else {
   6473                 // This case should hopefully never or seldom happen
   6474                 canvas = new Canvas(bitmap);
   6475             }
   6476 
   6477             if (clear) {
   6478                 bitmap.eraseColor(drawingCacheBackgroundColor);
   6479             }
   6480 
   6481             computeScroll();
   6482             final int restoreCount = canvas.save();
   6483 
   6484             if (autoScale && scalingRequired) {
   6485                 final float scale = attachInfo.mApplicationScale;
   6486                 canvas.scale(scale, scale);
   6487             }
   6488 
   6489             canvas.translate(-mScrollX, -mScrollY);
   6490 
   6491             mPrivateFlags |= DRAWN;
   6492             mPrivateFlags |= DRAWING_CACHE_VALID;
   6493 
   6494             // Fast path for layouts with no backgrounds
   6495             if ((mPrivateFlags & SKIP_DRAW) == SKIP_DRAW) {
   6496                 if (ViewDebug.TRACE_HIERARCHY) {
   6497                     ViewDebug.trace(this, ViewDebug.HierarchyTraceType.DRAW);
   6498                 }
   6499                 mPrivateFlags &= ~DIRTY_MASK;
   6500                 dispatchDraw(canvas);
   6501             } else {
   6502                 draw(canvas);
   6503             }
   6504 
   6505             canvas.restoreToCount(restoreCount);
   6506 
   6507             if (attachInfo != null) {
   6508                 // Restore the cached Canvas for our siblings
   6509                 attachInfo.mCanvas = canvas;
   6510             }
   6511         }
   6512     }
   6513 
   6514     /**
   6515      * Create a snapshot of the view into a bitmap.  We should probably make
   6516      * some form of this public, but should think about the API.
   6517      */
   6518     Bitmap createSnapshot(Bitmap.Config quality, int backgroundColor, boolean skipChildren) {
   6519         int width = mRight - mLeft;
   6520         int height = mBottom - mTop;
   6521 
   6522         final AttachInfo attachInfo = mAttachInfo;
   6523         final float scale = attachInfo != null ? attachInfo.mApplicationScale : 1.0f;
   6524         width = (int) ((width * scale) + 0.5f);
   6525         height = (int) ((height * scale) + 0.5f);
   6526 
   6527         Bitmap bitmap = Bitmap.createBitmap(width > 0 ? width : 1, height > 0 ? height : 1, quality);
   6528         if (bitmap == null) {
   6529             throw new OutOfMemoryError();
   6530         }
   6531 
   6532         bitmap.setDensity(getResources().getDisplayMetrics().densityDpi);
   6533 
   6534         Canvas canvas;
   6535         if (attachInfo != null) {
   6536             canvas = attachInfo.mCanvas;
   6537             if (canvas == null) {
   6538                 canvas = new Canvas();
   6539             }
   6540             canvas.setBitmap(bitmap);
   6541             // Temporarily clobber the cached Canvas in case one of our children
   6542             // is also using a drawing cache. Without this, the children would
   6543             // steal the canvas by attaching their own bitmap to it and bad, bad
   6544             // things would happen (invisible views, corrupted drawings, etc.)
   6545             attachInfo.mCanvas = null;
   6546         } else {
   6547             // This case should hopefully never or seldom happen
   6548             canvas = new Canvas(bitmap);
   6549         }
   6550 
   6551         if ((backgroundColor & 0xff000000) != 0) {
   6552             bitmap.eraseColor(backgroundColor);
   6553         }
   6554 
   6555         computeScroll();
   6556         final int restoreCount = canvas.save();
   6557         canvas.scale(scale, scale);
   6558         canvas.translate(-mScrollX, -mScrollY);
   6559 
   6560         // Temporarily remove the dirty mask
   6561         int flags = mPrivateFlags;
   6562         mPrivateFlags &= ~DIRTY_MASK;
   6563 
   6564         // Fast path for layouts with no backgrounds
   6565         if ((mPrivateFlags & SKIP_DRAW) == SKIP_DRAW) {
   6566             dispatchDraw(canvas);
   6567         } else {
   6568             draw(canvas);
   6569         }
   6570 
   6571         mPrivateFlags = flags;
   6572 
   6573         canvas.restoreToCount(restoreCount);
   6574 
   6575         if (attachInfo != null) {
   6576             // Restore the cached Canvas for our siblings
   6577             attachInfo.mCanvas = canvas;
   6578         }
   6579 
   6580         return bitmap;
   6581     }
   6582 
   6583     /**
   6584      * Indicates whether this View is currently in edit mode. A View is usually
   6585      * in edit mode when displayed within a developer tool. For instance, if
   6586      * this View is being drawn by a visual user interface builder, this method
   6587      * should return true.
   6588      *
   6589      * Subclasses should check the return value of this method to provide
   6590      * different behaviors if their normal behavior might interfere with the
   6591      * host environment. For instance: the class spawns a thread in its
   6592      * constructor, the drawing code relies on device-specific features, etc.
   6593      *
   6594      * This method is usually checked in the drawing code of custom widgets.
   6595      *
   6596      * @return True if this View is in edit mode, false otherwise.
   6597      */
   6598     public boolean isInEditMode() {
   6599         return false;
   6600     }
   6601 
   6602     /**
   6603      * If the View draws content inside its padding and enables fading edges,
   6604      * it needs to support padding offsets. Padding offsets are added to the
   6605      * fading edges to extend the length of the fade so that it covers pixels
   6606      * drawn inside the padding.
   6607      *
   6608      * Subclasses of this class should override this method if they need
   6609      * to draw content inside the padding.
   6610      *
   6611      * @return True if padding offset must be applied, false otherwise.
   6612      *
   6613      * @see #getLeftPaddingOffset()
   6614      * @see #getRightPaddingOffset()
   6615      * @see #getTopPaddingOffset()
   6616      * @see #getBottomPaddingOffset()
   6617      *
   6618      * @since CURRENT
   6619      */
   6620     protected boolean isPaddingOffsetRequired() {
   6621         return false;
   6622     }
   6623 
   6624     /**
   6625      * Amount by which to extend the left fading region. Called only when
   6626      * {@link #isPaddingOffsetRequired()} returns true.
   6627      *
   6628      * @return The left padding offset in pixels.
   6629      *
   6630      * @see #isPaddingOffsetRequired()
   6631      *
   6632      * @since CURRENT
   6633      */
   6634     protected int getLeftPaddingOffset() {
   6635         return 0;
   6636     }
   6637 
   6638     /**
   6639      * Amount by which to extend the right fading region. Called only when
   6640      * {@link #isPaddingOffsetRequired()} returns true.
   6641      *
   6642      * @return The right padding offset in pixels.
   6643      *
   6644      * @see #isPaddingOffsetRequired()
   6645      *
   6646      * @since CURRENT
   6647      */
   6648     protected int getRightPaddingOffset() {
   6649         return 0;
   6650     }
   6651 
   6652     /**
   6653      * Amount by which to extend the top fading region. Called only when
   6654      * {@link #isPaddingOffsetRequired()} returns true.
   6655      *
   6656      * @return The top padding offset in pixels.
   6657      *
   6658      * @see #isPaddingOffsetRequired()
   6659      *
   6660      * @since CURRENT
   6661      */
   6662     protected int getTopPaddingOffset() {
   6663         return 0;
   6664     }
   6665 
   6666     /**
   6667      * Amount by which to extend the bottom fading region. Called only when
   6668      * {@link #isPaddingOffsetRequired()} returns true.
   6669      *
   6670      * @return The bottom padding offset in pixels.
   6671      *
   6672      * @see #isPaddingOffsetRequired()
   6673      *
   6674      * @since CURRENT
   6675      */
   6676     protected int getBottomPaddingOffset() {
   6677         return 0;
   6678     }
   6679 
   6680     /**
   6681      * Manually render this view (and all of its children) to the given Canvas.
   6682      * The view must have already done a full layout before this function is
   6683      * called.  When implementing a view, do not override this method; instead,
   6684      * you should implement {@link #onDraw}.
   6685      *
   6686      * @param canvas The Canvas to which the View is rendered.
   6687      */
   6688     public void draw(Canvas canvas) {
   6689         if (ViewDebug.TRACE_HIERARCHY) {
   6690             ViewDebug.trace(this, ViewDebug.HierarchyTraceType.DRAW);
   6691         }
   6692 
   6693         final int privateFlags = mPrivateFlags;
   6694         final boolean dirtyOpaque = (privateFlags & DIRTY_MASK) == DIRTY_OPAQUE &&
   6695                 (mAttachInfo == null || !mAttachInfo.mIgnoreDirtyState);
   6696         mPrivateFlags = (privateFlags & ~DIRTY_MASK) | DRAWN;
   6697 
   6698         /*
   6699          * Draw traversal performs several drawing steps which must be executed
   6700          * in the appropriate order:
   6701          *
   6702          *      1. Draw the background
   6703          *      2. If necessary, save the canvas' layers to prepare for fading
   6704          *      3. Draw view's content
   6705          *      4. Draw children
   6706          *      5. If necessary, draw the fading edges and restore layers
   6707          *      6. Draw decorations (scrollbars for instance)
   6708          */
   6709 
   6710         // Step 1, draw the background, if needed
   6711         int saveCount;
   6712 
   6713         if (!dirtyOpaque) {
   6714             final Drawable background = mBGDrawable;
   6715             if (background != null) {
   6716                 final int scrollX = mScrollX;
   6717                 final int scrollY = mScrollY;
   6718 
   6719                 if (mBackgroundSizeChanged) {
   6720                     background.setBounds(0, 0,  mRight - mLeft, mBottom - mTop);
   6721                     mBackgroundSizeChanged = false;
   6722                 }
   6723 
   6724                 if ((scrollX | scrollY) == 0) {
   6725                     background.draw(canvas);
   6726                 } else {
   6727                     canvas.translate(scrollX, scrollY);
   6728                     background.draw(canvas);
   6729                     canvas.translate(-scrollX, -scrollY);
   6730                 }
   6731             }
   6732         }
   6733 
   6734         // skip step 2 & 5 if possible (common case)
   6735         final int viewFlags = mViewFlags;
   6736         boolean horizontalEdges = (viewFlags & FADING_EDGE_HORIZONTAL) != 0;
   6737         boolean verticalEdges = (viewFlags & FADING_EDGE_VERTICAL) != 0;
   6738         if (!verticalEdges && !horizontalEdges) {
   6739             // Step 3, draw the content
   6740             if (!dirtyOpaque) onDraw(canvas);
   6741 
   6742             // Step 4, draw the children
   6743             dispatchDraw(canvas);
   6744 
   6745             // Step 6, draw decorations (scrollbars)
   6746             onDrawScrollBars(canvas);
   6747 
   6748             // we're done...
   6749             return;
   6750         }
   6751 
   6752         /*
   6753          * Here we do the full fledged routine...
   6754          * (this is an uncommon case where speed matters less,
   6755          * this is why we repeat some of the tests that have been
   6756          * done above)
   6757          */
   6758 
   6759         boolean drawTop = false;
   6760         boolean drawBottom = false;
   6761         boolean drawLeft = false;
   6762         boolean drawRight = false;
   6763 
   6764         float topFadeStrength = 0.0f;
   6765         float bottomFadeStrength = 0.0f;
   6766         float leftFadeStrength = 0.0f;
   6767         float rightFadeStrength = 0.0f;
   6768 
   6769         // Step 2, save the canvas' layers
   6770         int paddingLeft = mPaddingLeft;
   6771         int paddingTop = mPaddingTop;
   6772 
   6773         final boolean offsetRequired = isPaddingOffsetRequired();
   6774         if (offsetRequired) {
   6775             paddingLeft += getLeftPaddingOffset();
   6776             paddingTop += getTopPaddingOffset();
   6777         }
   6778 
   6779         int left = mScrollX + paddingLeft;
   6780         int right = left + mRight - mLeft - mPaddingRight - paddingLeft;
   6781         int top = mScrollY + paddingTop;
   6782         int bottom = top + mBottom - mTop - mPaddingBottom - paddingTop;
   6783 
   6784         if (offsetRequired) {
   6785             right += getRightPaddingOffset();
   6786             bottom += getBottomPaddingOffset();
   6787         }
   6788 
   6789         final ScrollabilityCache scrollabilityCache = mScrollCache;
   6790         int length = scrollabilityCache.fadingEdgeLength;
   6791 
   6792         // clip the fade length if top and bottom fades overlap
   6793         // overlapping fades produce odd-looking artifacts
   6794         if (verticalEdges && (top + length > bottom - length)) {
   6795             length = (bottom - top) / 2;
   6796         }
   6797 
   6798         // also clip horizontal fades if necessary
   6799         if (horizontalEdges && (left + length > right - length)) {
   6800             length = (right - left) / 2;
   6801         }
   6802 
   6803         if (verticalEdges) {
   6804             topFadeStrength = Math.max(0.0f, Math.min(1.0f, getTopFadingEdgeStrength()));
   6805             drawTop = topFadeStrength >= 0.0f;
   6806             bottomFadeStrength = Math.max(0.0f, Math.min(1.0f, getBottomFadingEdgeStrength()));
   6807             drawBottom = bottomFadeStrength >= 0.0f;
   6808         }
   6809 
   6810         if (horizontalEdges) {
   6811             leftFadeStrength = Math.max(0.0f, Math.min(1.0f, getLeftFadingEdgeStrength()));
   6812             drawLeft = leftFadeStrength >= 0.0f;
   6813             rightFadeStrength = Math.max(0.0f, Math.min(1.0f, getRightFadingEdgeStrength()));
   6814             drawRight = rightFadeStrength >= 0.0f;
   6815         }
   6816 
   6817         saveCount = canvas.getSaveCount();
   6818 
   6819         int solidColor = getSolidColor();
   6820         if (solidColor == 0) {
   6821             final int flags = Canvas.HAS_ALPHA_LAYER_SAVE_FLAG;
   6822 
   6823             if (drawTop) {
   6824                 canvas.saveLayer(left, top, right, top + length, null, flags);
   6825             }
   6826 
   6827             if (drawBottom) {
   6828                 canvas.saveLayer(left, bottom - length, right, bottom, null, flags);
   6829             }
   6830 
   6831             if (drawLeft) {
   6832                 canvas.saveLayer(left, top, left + length, bottom, null, flags);
   6833             }
   6834 
   6835             if (drawRight) {
   6836                 canvas.saveLayer(right - length, top, right, bottom, null, flags);
   6837             }
   6838         } else {
   6839             scrollabilityCache.setFadeColor(solidColor);
   6840         }
   6841 
   6842         // Step 3, draw the content
   6843         if (!dirtyOpaque) onDraw(canvas);
   6844 
   6845         // Step 4, draw the children
   6846         dispatchDraw(canvas);
   6847 
   6848         // Step 5, draw the fade effect and restore layers
   6849         final Paint p = scrollabilityCache.paint;
   6850         final Matrix matrix = scrollabilityCache.matrix;
   6851         final Shader fade = scrollabilityCache.shader;
   6852         final float fadeHeight = scrollabilityCache.fadingEdgeLength;
   6853 
   6854         if (drawTop) {
   6855             matrix.setScale(1, fadeHeight * topFadeStrength);
   6856             matrix.postTranslate(left, top);
   6857             fade.setLocalMatrix(matrix);
   6858             canvas.drawRect(left, top, right, top + length, p);
   6859         }
   6860 
   6861         if (drawBottom) {
   6862             matrix.setScale(1, fadeHeight * bottomFadeStrength);
   6863             matrix.postRotate(180);
   6864             matrix.postTranslate(left, bottom);
   6865             fade.setLocalMatrix(matrix);
   6866             canvas.drawRect(left, bottom - length, right, bottom, p);
   6867         }
   6868 
   6869         if (drawLeft) {
   6870             matrix.setScale(1, fadeHeight * leftFadeStrength);
   6871             matrix.postRotate(-90);
   6872             matrix.postTranslate(left, top);
   6873             fade.setLocalMatrix(matrix);
   6874             canvas.drawRect(left, top, left + length, bottom, p);
   6875         }
   6876 
   6877         if (drawRight) {
   6878             matrix.setScale(1, fadeHeight * rightFadeStrength);
   6879             matrix.postRotate(90);
   6880             matrix.postTranslate(right, top);
   6881             fade.setLocalMatrix(matrix);
   6882             canvas.drawRect(right - length, top, right, bottom, p);
   6883         }
   6884 
   6885         canvas.restoreToCount(saveCount);
   6886 
   6887         // Step 6, draw decorations (scrollbars)
   6888         onDrawScrollBars(canvas);
   6889     }
   6890 
   6891     /**
   6892      * Override this if your view is known to always be drawn on top of a solid color background,
   6893      * and needs to draw fading edges. Returning a non-zero color enables the view system to
   6894      * optimize the drawing of the fading edges. If you do return a non-zero color, the alpha
   6895      * should be set to 0xFF.
   6896      *
   6897      * @see #setVerticalFadingEdgeEnabled
   6898      * @see #setHorizontalFadingEdgeEnabled
   6899      *
   6900      * @return The known solid color background for this view, or 0 if the color may vary
   6901      */
   6902     public int getSolidColor() {
   6903         return 0;
   6904     }
   6905 
   6906     /**
   6907      * Build a human readable string representation of the specified view flags.
   6908      *
   6909      * @param flags the view flags to convert to a string
   6910      * @return a String representing the supplied flags
   6911      */
   6912     private static String printFlags(int flags) {
   6913         String output = "";
   6914         int numFlags = 0;
   6915         if ((flags & FOCUSABLE_MASK) == FOCUSABLE) {
   6916             output += "TAKES_FOCUS";
   6917             numFlags++;
   6918         }
   6919 
   6920         switch (flags & VISIBILITY_MASK) {
   6921         case INVISIBLE:
   6922             if (numFlags > 0) {
   6923                 output += " ";
   6924             }
   6925             output += "INVISIBLE";
   6926             // USELESS HERE numFlags++;
   6927             break;
   6928         case GONE:
   6929             if (numFlags > 0) {
   6930                 output += " ";
   6931             }
   6932             output += "GONE";
   6933             // USELESS HERE numFlags++;
   6934             break;
   6935         default:
   6936             break;
   6937         }
   6938         return output;
   6939     }
   6940 
   6941     /**
   6942      * Build a human readable string representation of the specified private
   6943      * view flags.
   6944      *
   6945      * @param privateFlags the private view flags to convert to a string
   6946      * @return a String representing the supplied flags
   6947      */
   6948     private static String printPrivateFlags(int privateFlags) {
   6949         String output = "";
   6950         int numFlags = 0;
   6951 
   6952         if ((privateFlags & WANTS_FOCUS) == WANTS_FOCUS) {
   6953             output += "WANTS_FOCUS";
   6954             numFlags++;
   6955         }
   6956 
   6957         if ((privateFlags & FOCUSED) == FOCUSED) {
   6958             if (numFlags > 0) {
   6959                 output += " ";
   6960             }
   6961             output += "FOCUSED";
   6962             numFlags++;
   6963         }
   6964 
   6965         if ((privateFlags & SELECTED) == SELECTED) {
   6966             if (numFlags > 0) {
   6967                 output += " ";
   6968             }
   6969             output += "SELECTED";
   6970             numFlags++;
   6971         }
   6972 
   6973         if ((privateFlags & IS_ROOT_NAMESPACE) == IS_ROOT_NAMESPACE) {
   6974             if (numFlags > 0) {
   6975                 output += " ";
   6976             }
   6977             output += "IS_ROOT_NAMESPACE";
   6978             numFlags++;
   6979         }
   6980 
   6981         if ((privateFlags & HAS_BOUNDS) == HAS_BOUNDS) {
   6982             if (numFlags > 0) {
   6983                 output += " ";
   6984             }
   6985             output += "HAS_BOUNDS";
   6986             numFlags++;
   6987         }
   6988 
   6989         if ((privateFlags & DRAWN) == DRAWN) {
   6990             if (numFlags > 0) {
   6991                 output += " ";
   6992             }
   6993             output += "DRAWN";
   6994             // USELESS HERE numFlags++;
   6995         }
   6996         return output;
   6997     }
   6998 
   6999     /**
   7000      * <p>Indicates whether or not this view's layout will be requested during
   7001      * the next hierarchy layout pass.</p>
   7002      *
   7003      * @return true if the layout will be forced during next layout pass
   7004      */
   7005     public boolean isLayoutRequested() {
   7006         return (mPrivateFlags & FORCE_LAYOUT) == FORCE_LAYOUT;
   7007     }
   7008 
   7009     /**
   7010      * Assign a size and position to a view and all of its
   7011      * descendants
   7012      *
   7013      * <p>This is the second phase of the layout mechanism.
   7014      * (The first is measuring). In this phase, each parent calls
   7015      * layout on all of its children to position them.
   7016      * This is typically done using the child measurements
   7017      * that were stored in the measure pass().
   7018      *
   7019      * Derived classes with children should override
   7020      * onLayout. In that method, they should
   7021      * call layout on each of their their children.
   7022      *
   7023      * @param l Left position, relative to parent
   7024      * @param t Top position, relative to parent
   7025      * @param r Right position, relative to parent
   7026      * @param b Bottom position, relative to parent
   7027      */
   7028     public final void layout(int l, int t, int r, int b) {
   7029         boolean changed = setFrame(l, t, r, b);
   7030         if (changed || (mPrivateFlags & LAYOUT_REQUIRED) == LAYOUT_REQUIRED) {
   7031             if (ViewDebug.TRACE_HIERARCHY) {
   7032                 ViewDebug.trace(this, ViewDebug.HierarchyTraceType.ON_LAYOUT);
   7033             }
   7034 
   7035             onLayout(changed, l, t, r, b);
   7036             mPrivateFlags &= ~LAYOUT_REQUIRED;
   7037         }
   7038         mPrivateFlags &= ~FORCE_LAYOUT;
   7039     }
   7040 
   7041     /**
   7042      * Called from layout when this view should
   7043      * assign a size and position to each of its children.
   7044      *
   7045      * Derived classes with children should override
   7046      * this method and call layout on each of
   7047      * their their children.
   7048      * @param changed This is a new size or position for this view
   7049      * @param left Left position, relative to parent
   7050      * @param top Top position, relative to parent
   7051      * @param right Right position, relative to parent
   7052      * @param bottom Bottom position, relative to parent
   7053      */
   7054     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
   7055     }
   7056 
   7057     /**
   7058      * Assign a size and position to this view.
   7059      *
   7060      * This is called from layout.
   7061      *
   7062      * @param left Left position, relative to parent
   7063      * @param top Top position, relative to parent
   7064      * @param right Right position, relative to parent
   7065      * @param bottom Bottom position, relative to parent
   7066      * @return true if the new size and position are different than the
   7067      *         previous ones
   7068      * {@hide}
   7069      */
   7070     protected boolean setFrame(int left, int top, int right, int bottom) {
   7071         boolean changed = false;
   7072 
   7073         if (DBG) {
   7074             Log.d("View", this + " View.setFrame(" + left + "," + top + ","
   7075                     + right + "," + bottom + ")");
   7076         }
   7077 
   7078         if (mLeft != left || mRight != right || mTop != top || mBottom != bottom) {
   7079             changed = true;
   7080 
   7081             // Remember our drawn bit
   7082             int drawn = mPrivateFlags & DRAWN;
   7083 
   7084             // Invalidate our old position
   7085             invalidate();
   7086 
   7087 
   7088             int oldWidth = mRight - mLeft;
   7089             int oldHeight = mBottom - mTop;
   7090 
   7091             mLeft = left;
   7092             mTop = top;
   7093             mRight = right;
   7094             mBottom = bottom;
   7095 
   7096             mPrivateFlags |= HAS_BOUNDS;
   7097 
   7098             int newWidth = right - left;
   7099             int newHeight = bottom - top;
   7100 
   7101             if (newWidth != oldWidth || newHeight != oldHeight) {
   7102                 onSizeChanged(newWidth, newHeight, oldWidth, oldHeight);
   7103             }
   7104 
   7105             if ((mViewFlags & VISIBILITY_MASK) == VISIBLE) {
   7106                 // If we are visible, force the DRAWN bit to on so that
   7107                 // this invalidate will go through (at least to our parent).
   7108                 // This is because someone may have invalidated this view
   7109                 // before this call to setFrame came in, therby clearing
   7110                 // the DRAWN bit.
   7111                 mPrivateFlags |= DRAWN;
   7112                 invalidate();
   7113             }
   7114 
   7115             // Reset drawn bit to original value (invalidate turns it off)
   7116             mPrivateFlags |= drawn;
   7117 
   7118             mBackgroundSizeChanged = true;
   7119         }
   7120         return changed;
   7121     }
   7122 
   7123     /**
   7124      * Finalize inflating a view from XML.  This is called as the last phase
   7125      * of inflation, after all child views have been added.
   7126      *
   7127      * <p>Even if the subclass overrides onFinishInflate, they should always be
   7128      * sure to call the super method, so that we get called.
   7129      */
   7130     protected void onFinishInflate() {
   7131     }
   7132 
   7133     /**
   7134      * Returns the resources associated with this view.
   7135      *
   7136      * @return Resources object.
   7137      */
   7138     public Resources getResources() {
   7139         return mResources;
   7140     }
   7141 
   7142     /**
   7143      * Invalidates the specified Drawable.
   7144      *
   7145      * @param drawable the drawable to invalidate
   7146      */
   7147     public void invalidateDrawable(Drawable drawable) {
   7148         if (verifyDrawable(drawable)) {
   7149             final Rect dirty = drawable.getBounds();
   7150             final int scrollX = mScrollX;
   7151             final int scrollY = mScrollY;
   7152 
   7153             invalidate(dirty.left + scrollX, dirty.top + scrollY,
   7154                     dirty.right + scrollX, dirty.bottom + scrollY);
   7155         }
   7156     }
   7157 
   7158     /**
   7159      * Schedules an action on a drawable to occur at a specified time.
   7160      *
   7161      * @param who the recipient of the action
   7162      * @param what the action to run on the drawable
   7163      * @param when the time at which the action must occur. Uses the
   7164      *        {@link SystemClock#uptimeMillis} timebase.
   7165      */
   7166     public void scheduleDrawable(Drawable who, Runnable what, long when) {
   7167         if (verifyDrawable(who) && what != null && mAttachInfo != null) {
   7168             mAttachInfo.mHandler.postAtTime(what, who, when);
   7169         }
   7170     }
   7171 
   7172     /**
   7173      * Cancels a scheduled action on a drawable.
   7174      *
   7175      * @param who the recipient of the action
   7176      * @param what the action to cancel
   7177      */
   7178     public void unscheduleDrawable(Drawable who, Runnable what) {
   7179         if (verifyDrawable(who) && what != null && mAttachInfo != null) {
   7180             mAttachInfo.mHandler.removeCallbacks(what, who);
   7181         }
   7182     }
   7183 
   7184     /**
   7185      * Unschedule any events associated with the given Drawable.  This can be
   7186      * used when selecting a new Drawable into a view, so that the previous
   7187      * one is completely unscheduled.
   7188      *
   7189      * @param who The Drawable to unschedule.
   7190      *
   7191      * @see #drawableStateChanged
   7192      */
   7193     public void unscheduleDrawable(Drawable who) {
   7194         if (mAttachInfo != null) {
   7195             mAttachInfo.mHandler.removeCallbacksAndMessages(who);
   7196         }
   7197     }
   7198 
   7199     /**
   7200      * If your view subclass is displaying its own Drawable objects, it should
   7201      * override this function and return true for any Drawable it is
   7202      * displaying.  This allows animations for those drawables to be
   7203      * scheduled.
   7204      *
   7205      * <p>Be sure to call through to the super class when overriding this
   7206      * function.
   7207      *
   7208      * @param who The Drawable to verify.  Return true if it is one you are
   7209      *            displaying, else return the result of calling through to the
   7210      *            super class.
   7211      *
   7212      * @return boolean If true than the Drawable is being displayed in the
   7213      *         view; else false and it is not allowed to animate.
   7214      *
   7215      * @see #unscheduleDrawable
   7216      * @see #drawableStateChanged
   7217      */
   7218     protected boolean verifyDrawable(Drawable who) {
   7219         return who == mBGDrawable;
   7220     }
   7221 
   7222     /**
   7223      * This function is called whenever the state of the view changes in such
   7224      * a way that it impacts the state of drawables being shown.
   7225      *
   7226      * <p>Be sure to call through to the superclass when overriding this
   7227      * function.
   7228      *
   7229      * @see Drawable#setState
   7230      */
   7231     protected void drawableStateChanged() {
   7232         Drawable d = mBGDrawable;
   7233         if (d != null && d.isStateful()) {
   7234             d.setState(getDrawableState());
   7235         }
   7236     }
   7237 
   7238     /**
   7239      * Call this to force a view to update its drawable state. This will cause
   7240      * drawableStateChanged to be called on this view. Views that are interested
   7241      * in the new state should call getDrawableState.
   7242      *
   7243      * @see #drawableStateChanged
   7244      * @see #getDrawableState
   7245      */
   7246     public void refreshDrawableState() {
   7247         mPrivateFlags |= DRAWABLE_STATE_DIRTY;
   7248         drawableStateChanged();
   7249 
   7250         ViewParent parent = mParent;
   7251         if (parent != null) {
   7252             parent.childDrawableStateChanged(this);
   7253         }
   7254     }
   7255 
   7256     /**
   7257      * Return an array of resource IDs of the drawable states representing the
   7258      * current state of the view.
   7259      *
   7260      * @return The current drawable state
   7261      *
   7262      * @see Drawable#setState
   7263      * @see #drawableStateChanged
   7264      * @see #onCreateDrawableState
   7265      */
   7266     public final int[] getDrawableState() {
   7267         if ((mDrawableState != null) && ((mPrivateFlags & DRAWABLE_STATE_DIRTY) == 0)) {
   7268             return mDrawableState;
   7269         } else {
   7270             mDrawableState = onCreateDrawableState(0);
   7271             mPrivateFlags &= ~DRAWABLE_STATE_DIRTY;
   7272             return mDrawableState;
   7273         }
   7274     }
   7275 
   7276     /**
   7277      * Generate the new {@link android.graphics.drawable.Drawable} state for
   7278      * this view. This is called by the view
   7279      * system when the cached Drawable state is determined to be invalid.  To
   7280      * retrieve the current state, you should use {@link #getDrawableState}.
   7281      *
   7282      * @param extraSpace if non-zero, this is the number of extra entries you
   7283      * would like in the returned array in which you can place your own
   7284      * states.
   7285      *
   7286      * @return Returns an array holding the current {@link Drawable} state of
   7287      * the view.
   7288      *
   7289      * @see #mergeDrawableStates
   7290      */
   7291     protected int[] onCreateDrawableState(int extraSpace) {
   7292         if ((mViewFlags & DUPLICATE_PARENT_STATE) == DUPLICATE_PARENT_STATE &&
   7293                 mParent instanceof View) {
   7294             return ((View) mParent).onCreateDrawableState(extraSpace);
   7295         }
   7296 
   7297         int[] drawableState;
   7298 
   7299         int privateFlags = mPrivateFlags;
   7300 
   7301         int viewStateIndex = (((privateFlags & PRESSED) != 0) ? 1 : 0);
   7302 
   7303         viewStateIndex = (viewStateIndex << 1)
   7304                 + (((mViewFlags & ENABLED_MASK) == ENABLED) ? 1 : 0);
   7305 
   7306         viewStateIndex = (viewStateIndex << 1) + (isFocused() ? 1 : 0);
   7307 
   7308         viewStateIndex = (viewStateIndex << 1)
   7309                 + (((privateFlags & SELECTED) != 0) ? 1 : 0);
   7310 
   7311         final boolean hasWindowFocus = hasWindowFocus();
   7312         viewStateIndex = (viewStateIndex << 1) + (hasWindowFocus ? 1 : 0);
   7313 
   7314         drawableState = VIEW_STATE_SETS[viewStateIndex];
   7315 
   7316         //noinspection ConstantIfStatement
   7317         if (false) {
   7318             Log.i("View", "drawableStateIndex=" + viewStateIndex);
   7319             Log.i("View", toString()
   7320                     + " pressed=" + ((privateFlags & PRESSED) != 0)
   7321                     + " en=" + ((mViewFlags & ENABLED_MASK) == ENABLED)
   7322                     + " fo=" + hasFocus()
   7323                     + " sl=" + ((privateFlags & SELECTED) != 0)
   7324                     + " wf=" + hasWindowFocus
   7325                     + ": " + Arrays.toString(drawableState));
   7326         }
   7327 
   7328         if (extraSpace == 0) {
   7329             return drawableState;
   7330         }
   7331 
   7332         final int[] fullState;
   7333         if (drawableState != null) {
   7334             fullState = new int[drawableState.length + extraSpace];
   7335             System.arraycopy(drawableState, 0, fullState, 0, drawableState.length);
   7336         } else {
   7337             fullState = new int[extraSpace];
   7338         }
   7339 
   7340         return fullState;
   7341     }
   7342 
   7343     /**
   7344      * Merge your own state values in <var>additionalState</var> into the base
   7345      * state values <var>baseState</var> that were returned by
   7346      * {@link #onCreateDrawableState}.
   7347      *
   7348      * @param baseState The base state values returned by
   7349      * {@link #onCreateDrawableState}, which will be modified to also hold your
   7350      * own additional state values.
   7351      *
   7352      * @param additionalState The additional state values you would like
   7353      * added to <var>baseState</var>; this array is not modified.
   7354      *
   7355      * @return As a convenience, the <var>baseState</var> array you originally
   7356      * passed into the function is returned.
   7357      *
   7358      * @see #onCreateDrawableState
   7359      */
   7360     protected static int[] mergeDrawableStates(int[] baseState, int[] additionalState) {
   7361         final int N = baseState.length;
   7362         int i = N - 1;
   7363         while (i >= 0 && baseState[i] == 0) {
   7364             i--;
   7365         }
   7366         System.arraycopy(additionalState, 0, baseState, i + 1, additionalState.length);
   7367         return baseState;
   7368     }
   7369 
   7370     /**
   7371      * Sets the background color for this view.
   7372      * @param color the color of the background
   7373      */
   7374     @RemotableViewMethod
   7375     public void setBackgroundColor(int color) {
   7376         setBackgroundDrawable(new ColorDrawable(color));
   7377     }
   7378 
   7379     /**
   7380      * Set the background to a given resource. The resource should refer to
   7381      * a Drawable object or 0 to remove the background.
   7382      * @param resid The identifier of the resource.
   7383      * @attr ref android.R.styleable#View_background
   7384      */
   7385     @RemotableViewMethod
   7386     public void setBackgroundResource(int resid) {
   7387         if (resid != 0 && resid == mBackgroundResource) {
   7388             return;
   7389         }
   7390 
   7391         Drawable d= null;
   7392         if (resid != 0) {
   7393             d = mResources.getDrawable(resid);
   7394         }
   7395         setBackgroundDrawable(d);
   7396 
   7397         mBackgroundResource = resid;
   7398     }
   7399 
   7400     /**
   7401      * Set the background to a given Drawable, or remove the background. If the
   7402      * background has padding, this View's padding is set to the background's
   7403      * padding. However, when a background is removed, this View's padding isn't
   7404      * touched. If setting the padding is desired, please use
   7405      * {@link #setPadding(int, int, int, int)}.
   7406      *
   7407      * @param d The Drawable to use as the background, or null to remove the
   7408      *        background
   7409      */
   7410     public void setBackgroundDrawable(Drawable d) {
   7411         boolean requestLayout = false;
   7412 
   7413         mBackgroundResource = 0;
   7414 
   7415         /*
   7416          * Regardless of whether we're setting a new background or not, we want
   7417          * to clear the previous drawable.
   7418          */
   7419         if (mBGDrawable != null) {
   7420             mBGDrawable.setCallback(null);
   7421             unscheduleDrawable(mBGDrawable);
   7422         }
   7423 
   7424         if (d != null) {
   7425             Rect padding = sThreadLocal.get();
   7426             if (padding == null) {
   7427                 padding = new Rect();
   7428                 sThreadLocal.set(padding);
   7429             }
   7430             if (d.getPadding(padding)) {
   7431                 setPadding(padding.left, padding.top, padding.right, padding.bottom);
   7432             }
   7433 
   7434             // Compare the minimum sizes of the old Drawable and the new.  If there isn't an old or
   7435             // if it has a different minimum size, we should layout again
   7436             if (mBGDrawable == null || mBGDrawable.getMinimumHeight() != d.getMinimumHeight() ||
   7437                     mBGDrawable.getMinimumWidth() != d.getMinimumWidth()) {
   7438                 requestLayout = true;
   7439             }
   7440 
   7441             d.setCallback(this);
   7442             if (d.isStateful()) {
   7443                 d.setState(getDrawableState());
   7444             }
   7445             d.setVisible(getVisibility() == VISIBLE, false);
   7446             mBGDrawable = d;
   7447 
   7448             if ((mPrivateFlags & SKIP_DRAW) != 0) {
   7449                 mPrivateFlags &= ~SKIP_DRAW;
   7450                 mPrivateFlags |= ONLY_DRAWS_BACKGROUND;
   7451                 requestLayout = true;
   7452             }
   7453         } else {
   7454             /* Remove the background */
   7455             mBGDrawable = null;
   7456 
   7457             if ((mPrivateFlags & ONLY_DRAWS_BACKGROUND) != 0) {
   7458                 /*
   7459                  * This view ONLY drew the background before and we're removing
   7460                  * the background, so now it won't draw anything
   7461                  * (hence we SKIP_DRAW)
   7462                  */
   7463                 mPrivateFlags &= ~ONLY_DRAWS_BACKGROUND;
   7464                 mPrivateFlags |= SKIP_DRAW;
   7465             }
   7466 
   7467             /*
   7468              * When the background is set, we try to apply its padding to this
   7469              * View. When the background is removed, we don't touch this View's
   7470              * padding. This is noted in the Javadocs. Hence, we don't need to
   7471              * requestLayout(), the invalidate() below is sufficient.
   7472              */
   7473 
   7474             // The old background's minimum size could have affected this
   7475             // View's layout, so let's requestLayout
   7476             requestLayout = true;
   7477         }
   7478 
   7479         computeOpaqueFlags();
   7480 
   7481         if (requestLayout) {
   7482             requestLayout();
   7483         }
   7484 
   7485         mBackgroundSizeChanged = true;
   7486         invalidate();
   7487     }
   7488 
   7489     /**
   7490      * Gets the background drawable
   7491      * @return The drawable used as the background for this view, if any.
   7492      */
   7493     public Drawable getBackground() {
   7494         return mBGDrawable;
   7495     }
   7496 
   7497     /**
   7498      * Sets the padding. The view may add on the space required to display
   7499      * the scrollbars, depending on the style and visibility of the scrollbars.
   7500      * So the values returned from {@link #getPaddingLeft}, {@link #getPaddingTop},
   7501      * {@link #getPaddingRight} and {@link #getPaddingBottom} may be different
   7502      * from the values set in this call.
   7503      *
   7504      * @attr ref android.R.styleable#View_padding
   7505      * @attr ref android.R.styleable#View_paddingBottom
   7506      * @attr ref android.R.styleable#View_paddingLeft
   7507      * @attr ref android.R.styleable#View_paddingRight
   7508      * @attr ref android.R.styleable#View_paddingTop
   7509      * @param left the left padding in pixels
   7510      * @param top the top padding in pixels
   7511      * @param right the right padding in pixels
   7512      * @param bottom the bottom padding in pixels
   7513      */
   7514     public void setPadding(int left, int top, int right, int bottom) {
   7515         boolean changed = false;
   7516 
   7517         mUserPaddingRight = right;
   7518         mUserPaddingBottom = bottom;
   7519 
   7520         final int viewFlags = mViewFlags;
   7521 
   7522         // Common case is there are no scroll bars.
   7523         if ((viewFlags & (SCROLLBARS_VERTICAL|SCROLLBARS_HORIZONTAL)) != 0) {
   7524             // TODO: Deal with RTL languages to adjust left padding instead of right.
   7525             if ((viewFlags & SCROLLBARS_VERTICAL) != 0) {
   7526                 right += (viewFlags & SCROLLBARS_INSET_MASK) == 0
   7527                         ? 0 : getVerticalScrollbarWidth();
   7528             }
   7529             if ((viewFlags & SCROLLBARS_HORIZONTAL) == 0) {
   7530                 bottom += (viewFlags & SCROLLBARS_INSET_MASK) == 0
   7531                         ? 0 : getHorizontalScrollbarHeight();
   7532             }
   7533         }
   7534 
   7535         if (mPaddingLeft != left) {
   7536             changed = true;
   7537             mPaddingLeft = left;
   7538         }
   7539         if (mPaddingTop != top) {
   7540             changed = true;
   7541             mPaddingTop = top;
   7542         }
   7543         if (mPaddingRight != right) {
   7544             changed = true;
   7545             mPaddingRight = right;
   7546         }
   7547         if (mPaddingBottom != bottom) {
   7548             changed = true;
   7549             mPaddingBottom = bottom;
   7550         }
   7551 
   7552         if (changed) {
   7553             requestLayout();
   7554         }
   7555     }
   7556 
   7557     /**
   7558      * Returns the top padding of this view.
   7559      *
   7560      * @return the top padding in pixels
   7561      */
   7562     public int getPaddingTop() {
   7563         return mPaddingTop;
   7564     }
   7565 
   7566     /**
   7567      * Returns the bottom padding of this view. If there are inset and enabled
   7568      * scrollbars, this value may include the space required to display the
   7569      * scrollbars as well.
   7570      *
   7571      * @return the bottom padding in pixels
   7572      */
   7573     public int getPaddingBottom() {
   7574         return mPaddingBottom;
   7575     }
   7576 
   7577     /**
   7578      * Returns the left padding of this view. If there are inset and enabled
   7579      * scrollbars, this value may include the space required to display the
   7580      * scrollbars as well.
   7581      *
   7582      * @return the left padding in pixels
   7583      */
   7584     public int getPaddingLeft() {
   7585         return mPaddingLeft;
   7586     }
   7587 
   7588     /**
   7589      * Returns the right padding of this view. If there are inset and enabled
   7590      * scrollbars, this value may include the space required to display the
   7591      * scrollbars as well.
   7592      *
   7593      * @return the right padding in pixels
   7594      */
   7595     public int getPaddingRight() {
   7596         return mPaddingRight;
   7597     }
   7598 
   7599     /**
   7600      * Changes the selection state of this view. A view can be selected or not.
   7601      * Note that selection is not the same as focus. Views are typically
   7602      * selected in the context of an AdapterView like ListView or GridView;
   7603      * the selected view is the view that is highlighted.
   7604      *
   7605      * @param selected true if the view must be selected, false otherwise
   7606      */
   7607     public void setSelected(boolean selected) {
   7608         if (((mPrivateFlags & SELECTED) != 0) != selected) {
   7609             mPrivateFlags = (mPrivateFlags & ~SELECTED) | (selected ? SELECTED : 0);
   7610             if (!selected) resetPressedState();
   7611             invalidate();
   7612             refreshDrawableState();
   7613             dispatchSetSelected(selected);
   7614         }
   7615     }
   7616 
   7617     /**
   7618      * Dispatch setSelected to all of this View's children.
   7619      *
   7620      * @see #setSelected(boolean)
   7621      *
   7622      * @param selected The new selected state
   7623      */
   7624     protected void dispatchSetSelected(boolean selected) {
   7625     }
   7626 
   7627     /**
   7628      * Indicates the selection state of this view.
   7629      *
   7630      * @return true if the view is selected, false otherwise
   7631      */
   7632     @ViewDebug.ExportedProperty
   7633     public boolean isSelected() {
   7634         return (mPrivateFlags & SELECTED) != 0;
   7635     }
   7636 
   7637     /**
   7638      * Returns the ViewTreeObserver for this view's hierarchy. The view tree
   7639      * observer can be used to get notifications when global events, like
   7640      * layout, happen.
   7641      *
   7642      * The returned ViewTreeObserver observer is not guaranteed to remain
   7643      * valid for the lifetime of this View. If the caller of this method keeps
   7644      * a long-lived reference to ViewTreeObserver, it should always check for
   7645      * the return value of {@link ViewTreeObserver#isAlive()}.
   7646      *
   7647      * @return The ViewTreeObserver for this view's hierarchy.
   7648      */
   7649     public ViewTreeObserver getViewTreeObserver() {
   7650         if (mAttachInfo != null) {
   7651             return mAttachInfo.mTreeObserver;
   7652         }
   7653         if (mFloatingTreeObserver == null) {
   7654             mFloatingTreeObserver = new ViewTreeObserver();
   7655         }
   7656         return mFloatingTreeObserver;
   7657     }
   7658 
   7659     /**
   7660      * <p>Finds the topmost view in the current view hierarchy.</p>
   7661      *
   7662      * @return the topmost view containing this view
   7663      */
   7664     public View getRootView() {
   7665         if (mAttachInfo != null) {
   7666             final View v = mAttachInfo.mRootView;
   7667             if (v != null) {
   7668                 return v;
   7669             }
   7670         }
   7671 
   7672         View parent = this;
   7673 
   7674         while (parent.mParent != null && parent.mParent instanceof View) {
   7675             parent = (View) parent.mParent;
   7676         }
   7677 
   7678         return parent;
   7679     }
   7680 
   7681     /**
   7682      * <p>Computes the coordinates of this view on the screen. The argument
   7683      * must be an array of two integers. After the method returns, the array
   7684      * contains the x and y location in that order.</p>
   7685      *
   7686      * @param location an array of two integers in which to hold the coordinates
   7687      */
   7688     public void getLocationOnScreen(int[] location) {
   7689         getLocationInWindow(location);
   7690 
   7691         final AttachInfo info = mAttachInfo;
   7692         if (info != null) {
   7693             location[0] += info.mWindowLeft;
   7694             location[1] += info.mWindowTop;
   7695         }
   7696     }
   7697 
   7698     /**
   7699      * <p>Computes the coordinates of this view in its window. The argument
   7700      * must be an array of two integers. After the method returns, the array
   7701      * contains the x and y location in that order.</p>
   7702      *
   7703      * @param location an array of two integers in which to hold the coordinates
   7704      */
   7705     public void getLocationInWindow(int[] location) {
   7706         if (location == null || location.length < 2) {
   7707             throw new IllegalArgumentException("location must be an array of "
   7708                     + "two integers");
   7709         }
   7710 
   7711         location[0] = mLeft;
   7712         location[1] = mTop;
   7713 
   7714         ViewParent viewParent = mParent;
   7715         while (viewParent instanceof View) {
   7716             final View view = (View)viewParent;
   7717             location[0] += view.mLeft - view.mScrollX;
   7718             location[1] += view.mTop - view.mScrollY;
   7719             viewParent = view.mParent;
   7720         }
   7721 
   7722         if (viewParent instanceof ViewRoot) {
   7723             // *cough*
   7724             final ViewRoot vr = (ViewRoot)viewParent;
   7725             location[1] -= vr.mCurScrollY;
   7726         }
   7727     }
   7728 
   7729     /**
   7730      * {@hide}
   7731      * @param id the id of the view to be found
   7732      * @return the view of the specified id, null if cannot be found
   7733      */
   7734     protected View findViewTraversal(int id) {
   7735         if (id == mID) {
   7736             return this;
   7737         }
   7738         return null;
   7739     }
   7740 
   7741     /**
   7742      * {@hide}
   7743      * @param tag the tag of the view to be found
   7744      * @return the view of specified tag, null if cannot be found
   7745      */
   7746     protected View findViewWithTagTraversal(Object tag) {
   7747         if (tag != null && tag.equals(mTag)) {
   7748             return this;
   7749         }
   7750         return null;
   7751     }
   7752 
   7753     /**
   7754      * Look for a child view with the given id.  If this view has the given
   7755      * id, return this view.
   7756      *
   7757      * @param id The id to search for.
   7758      * @return The view that has the given id in the hierarchy or null
   7759      */
   7760     public final View findViewById(int id) {
   7761         if (id < 0) {
   7762             return null;
   7763         }
   7764         return findViewTraversal(id);
   7765     }
   7766 
   7767     /**
   7768      * Look for a child view with the given tag.  If this view has the given
   7769      * tag, return this view.
   7770      *
   7771      * @param tag The tag to search for, using "tag.equals(getTag())".
   7772      * @return The View that has the given tag in the hierarchy or null
   7773      */
   7774     public final View findViewWithTag(Object tag) {
   7775         if (tag == null) {
   7776             return null;
   7777         }
   7778         return findViewWithTagTraversal(tag);
   7779     }
   7780 
   7781     /**
   7782      * Sets the identifier for this view. The identifier does not have to be
   7783      * unique in this view's hierarchy. The identifier should be a positive
   7784      * number.
   7785      *
   7786      * @see #NO_ID
   7787      * @see #getId
   7788      * @see #findViewById
   7789      *
   7790      * @param id a number used to identify the view
   7791      *
   7792      * @attr ref android.R.styleable#View_id
   7793      */
   7794     public void setId(int id) {
   7795         mID = id;
   7796     }
   7797 
   7798     /**
   7799      * {@hide}
   7800      *
   7801      * @param isRoot true if the view belongs to the root namespace, false
   7802      *        otherwise
   7803      */
   7804     public void setIsRootNamespace(boolean isRoot) {
   7805         if (isRoot) {
   7806             mPrivateFlags |= IS_ROOT_NAMESPACE;
   7807         } else {
   7808             mPrivateFlags &= ~IS_ROOT_NAMESPACE;
   7809         }
   7810     }
   7811 
   7812     /**
   7813      * {@hide}
   7814      *
   7815      * @return true if the view belongs to the root namespace, false otherwise
   7816      */
   7817     public boolean isRootNamespace() {
   7818         return (mPrivateFlags&IS_ROOT_NAMESPACE) != 0;
   7819     }
   7820 
   7821     /**
   7822      * Returns this view's identifier.
   7823      *
   7824      * @return a positive integer used to identify the view or {@link #NO_ID}
   7825      *         if the view has no ID
   7826      *
   7827      * @see #setId
   7828      * @see #findViewById
   7829      * @attr ref android.R.styleable#View_id
   7830      */
   7831     @ViewDebug.CapturedViewProperty
   7832     public int getId() {
   7833         return mID;
   7834     }
   7835 
   7836     /**
   7837      * Returns this view's tag.
   7838      *
   7839      * @return the Object stored in this view as a tag
   7840      *
   7841      * @see #setTag(Object)
   7842      * @see #getTag(int)
   7843      */
   7844     @ViewDebug.ExportedProperty
   7845     public Object getTag() {
   7846         return mTag;
   7847     }
   7848 
   7849     /**
   7850      * Sets the tag associated with this view. A tag can be used to mark
   7851      * a view in its hierarchy and does not have to be unique within the
   7852      * hierarchy. Tags can also be used to store data within a view without
   7853      * resorting to another data structure.
   7854      *
   7855      * @param tag an Object to tag the view with
   7856      *
   7857      * @see #getTag()
   7858      * @see #setTag(int, Object)
   7859      */
   7860     public void setTag(final Object tag) {
   7861         mTag = tag;
   7862     }
   7863 
   7864     /**
   7865      * Returns the tag associated with this view and the specified key.
   7866      *
   7867      * @param key The key identifying the tag
   7868      *
   7869      * @return the Object stored in this view as a tag
   7870      *
   7871      * @see #setTag(int, Object)
   7872      * @see #getTag()
   7873      */
   7874     public Object getTag(int key) {
   7875         SparseArray<Object> tags = null;
   7876         synchronized (sTagsLock) {
   7877             if (sTags != null) {
   7878                 tags = sTags.get(this);
   7879             }
   7880         }
   7881 
   7882         if (tags != null) return tags.get(key);
   7883         return null;
   7884     }
   7885 
   7886     /**
   7887      * Sets a tag associated with this view and a key. A tag can be used
   7888      * to mark a view in its hierarchy and does not have to be unique within
   7889      * the hierarchy. Tags can also be used to store data within a view
   7890      * without resorting to another data structure.
   7891      *
   7892      * The specified key should be an id declared in the resources of the
   7893      * application to ensure it is unique. Keys identified as belonging to
   7894      * the Android framework or not associated with any package will cause
   7895      * an {@link IllegalArgumentException} to be thrown.
   7896      *
   7897      * @param key The key identifying the tag
   7898      * @param tag An Object to tag the view with
   7899      *
   7900      * @throws IllegalArgumentException If they specified key is not valid
   7901      *
   7902      * @see #setTag(Object)
   7903      * @see #getTag(int)
   7904      */
   7905     public void setTag(int key, final Object tag) {
   7906         // If the package id is 0x00 or 0x01, it's either an undefined package
   7907         // or a framework id
   7908         if ((key >>> 24) < 2) {
   7909             throw new IllegalArgumentException("The key must be an application-specific "
   7910                     + "resource id.");
   7911         }
   7912 
   7913         setTagInternal(this, key, tag);
   7914     }
   7915 
   7916     /**
   7917      * Variation of {@link #setTag(int, Object)} that enforces the key to be a
   7918      * framework id.
   7919      *
   7920      * @hide
   7921      */
   7922     public void setTagInternal(int key, Object tag) {
   7923         if ((key >>> 24) != 0x1) {
   7924             throw new IllegalArgumentException("The key must be a framework-specific "
   7925                     + "resource id.");
   7926         }
   7927 
   7928         setTagInternal(this, key, tag);
   7929     }
   7930 
   7931     private static void setTagInternal(View view, int key, Object tag) {
   7932         SparseArray<Object> tags = null;
   7933         synchronized (sTagsLock) {
   7934             if (sTags == null) {
   7935                 sTags = new WeakHashMap<View, SparseArray<Object>>();
   7936             } else {
   7937                 tags = sTags.get(view);
   7938             }
   7939         }
   7940 
   7941         if (tags == null) {
   7942             tags = new SparseArray<Object>(2);
   7943             synchronized (sTagsLock) {
   7944                 sTags.put(view, tags);
   7945             }
   7946         }
   7947 
   7948         tags.put(key, tag);
   7949     }
   7950 
   7951     /**
   7952      * @param consistency The type of consistency. See ViewDebug for more information.
   7953      *
   7954      * @hide
   7955      */
   7956     protected boolean dispatchConsistencyCheck(int consistency) {
   7957         return onConsistencyCheck(consistency);
   7958     }
   7959 
   7960     /**
   7961      * Method that subclasses should implement to check their consistency. The type of
   7962      * consistency check is indicated by the bit field passed as a parameter.
   7963      *
   7964      * @param consistency The type of consistency. See ViewDebug for more information.
   7965      *
   7966      * @throws IllegalStateException if the view is in an inconsistent state.
   7967      *
   7968      * @hide
   7969      */
   7970     protected boolean onConsistencyCheck(int consistency) {
   7971         boolean result = true;
   7972 
   7973         final boolean checkLayout = (consistency & ViewDebug.CONSISTENCY_LAYOUT) != 0;
   7974         final boolean checkDrawing = (consistency & ViewDebug.CONSISTENCY_DRAWING) != 0;
   7975 
   7976         if (checkLayout) {
   7977             if (getParent() == null) {
   7978                 result = false;
   7979                 android.util.Log.d(ViewDebug.CONSISTENCY_LOG_TAG,
   7980                         "View " + this + " does not have a parent.");
   7981             }
   7982 
   7983             if (mAttachInfo == null) {
   7984                 result = false;
   7985                 android.util.Log.d(ViewDebug.CONSISTENCY_LOG_TAG,
   7986                         "View " + this + " is not attached to a window.");
   7987             }
   7988         }
   7989 
   7990         if (checkDrawing) {
   7991             // Do not check the DIRTY/DRAWN flags because views can call invalidate()
   7992             // from their draw() method
   7993 
   7994             if ((mPrivateFlags & DRAWN) != DRAWN &&
   7995                     (mPrivateFlags & DRAWING_CACHE_VALID) == DRAWING_CACHE_VALID) {
   7996                 result = false;
   7997                 android.util.Log.d(ViewDebug.CONSISTENCY_LOG_TAG,
   7998                         "View " + this + " was invalidated but its drawing cache is valid.");
   7999             }
   8000         }
   8001 
   8002         return result;
   8003     }
   8004 
   8005     /**
   8006      * Prints information about this view in the log output, with the tag
   8007      * {@link #VIEW_LOG_TAG}.
   8008      *
   8009      * @hide
   8010      */
   8011     public void debug() {
   8012         debug(0);
   8013     }
   8014 
   8015     /**
   8016      * Prints information about this view in the log output, with the tag
   8017      * {@link #VIEW_LOG_TAG}. Each line in the output is preceded with an
   8018      * indentation defined by the <code>depth</code>.
   8019      *
   8020      * @param depth the indentation level
   8021      *
   8022      * @hide
   8023      */
   8024     protected void debug(int depth) {
   8025         String output = debugIndent(depth - 1);
   8026 
   8027         output += "+ " + this;
   8028         int id = getId();
   8029         if (id != -1) {
   8030             output += " (id=" + id + ")";
   8031         }
   8032         Object tag = getTag();
   8033         if (tag != null) {
   8034             output += " (tag=" + tag + ")";
   8035         }
   8036         Log.d(VIEW_LOG_TAG, output);
   8037 
   8038         if ((mPrivateFlags & FOCUSED) != 0) {
   8039             output = debugIndent(depth) + " FOCUSED";
   8040             Log.d(VIEW_LOG_TAG, output);
   8041         }
   8042 
   8043         output = debugIndent(depth);
   8044         output += "frame={" + mLeft + ", " + mTop + ", " + mRight
   8045                 + ", " + mBottom + "} scroll={" + mScrollX + ", " + mScrollY
   8046                 + "} ";
   8047         Log.d(VIEW_LOG_TAG, output);
   8048 
   8049         if (mPaddingLeft != 0 || mPaddingTop != 0 || mPaddingRight != 0
   8050                 || mPaddingBottom != 0) {
   8051             output = debugIndent(depth);
   8052             output += "padding={" + mPaddingLeft + ", " + mPaddingTop
   8053                     + ", " + mPaddingRight + ", " + mPaddingBottom + "}";
   8054             Log.d(VIEW_LOG_TAG, output);
   8055         }
   8056 
   8057         output = debugIndent(depth);
   8058         output += "mMeasureWidth=" + mMeasuredWidth +
   8059                 " mMeasureHeight=" + mMeasuredHeight;
   8060         Log.d(VIEW_LOG_TAG, output);
   8061 
   8062         output = debugIndent(depth);
   8063         if (mLayoutParams == null) {
   8064             output += "BAD! no layout params";
   8065         } else {
   8066             output = mLayoutParams.debug(output);
   8067         }
   8068         Log.d(VIEW_LOG_TAG, output);
   8069 
   8070         output = debugIndent(depth);
   8071         output += "flags={";
   8072         output += View.printFlags(mViewFlags);
   8073         output += "}";
   8074         Log.d(VIEW_LOG_TAG, output);
   8075 
   8076         output = debugIndent(depth);
   8077         output += "privateFlags={";
   8078         output += View.printPrivateFlags(mPrivateFlags);
   8079         output += "}";
   8080         Log.d(VIEW_LOG_TAG, output);
   8081     }
   8082 
   8083     /**
   8084      * Creates an string of whitespaces used for indentation.
   8085      *
   8086      * @param depth the indentation level
   8087      * @return a String containing (depth * 2 + 3) * 2 white spaces
   8088      *
   8089      * @hide
   8090      */
   8091     protected static String debugIndent(int depth) {
   8092         StringBuilder spaces = new StringBuilder((depth * 2 + 3) * 2);
   8093         for (int i = 0; i < (depth * 2) + 3; i++) {
   8094             spaces.append(' ').append(' ');
   8095         }
   8096         return spaces.toString();
   8097     }
   8098 
   8099     /**
   8100      * <p>Return the offset of the widget's text baseline from the widget's top
   8101      * boundary. If this widget does not support baseline alignment, this
   8102      * method returns -1. </p>
   8103      *
   8104      * @return the offset of the baseline within the widget's bounds or -1
   8105      *         if baseline alignment is not supported
   8106      */
   8107     @ViewDebug.ExportedProperty
   8108     public int getBaseline() {
   8109         return -1;
   8110     }
   8111 
   8112     /**
   8113      * Call this when something has changed which has invalidated the
   8114      * layout of this view. This will schedule a layout pass of the view
   8115      * tree.
   8116      */
   8117     public void requestLayout() {
   8118         if (ViewDebug.TRACE_HIERARCHY) {
   8119             ViewDebug.trace(this, ViewDebug.HierarchyTraceType.REQUEST_LAYOUT);
   8120         }
   8121 
   8122         mPrivateFlags |= FORCE_LAYOUT;
   8123 
   8124         if (mParent != null && !mParent.isLayoutRequested()) {
   8125             mParent.requestLayout();
   8126         }
   8127     }
   8128 
   8129     /**
   8130      * Forces this view to be laid out during the next layout pass.
   8131      * This method does not call requestLayout() or forceLayout()
   8132      * on the parent.
   8133      */
   8134     public void forceLayout() {
   8135         mPrivateFlags |= FORCE_LAYOUT;
   8136     }
   8137 
   8138     /**
   8139      * <p>
   8140      * This is called to find out how big a view should be. The parent
   8141      * supplies constraint information in the width and height parameters.
   8142      * </p>
   8143      *
   8144      * <p>
   8145      * The actual mesurement work of a view is performed in
   8146      * {@link #onMeasure(int, int)}, called by this method. Therefore, only
   8147      * {@link #onMeasure(int, int)} can and must be overriden by subclasses.
   8148      * </p>
   8149      *
   8150      *
   8151      * @param widthMeasureSpec Horizontal space requirements as imposed by the
   8152      *        parent
   8153      * @param heightMeasureSpec Vertical space requirements as imposed by the
   8154      *        parent
   8155      *
   8156      * @see #onMeasure(int, int)
   8157      */
   8158     public final void measure(int widthMeasureSpec, int heightMeasureSpec) {
   8159         if ((mPrivateFlags & FORCE_LAYOUT) == FORCE_LAYOUT ||
   8160                 widthMeasureSpec != mOldWidthMeasureSpec ||
   8161                 heightMeasureSpec != mOldHeightMeasureSpec) {
   8162 
   8163             // first clears the measured dimension flag
   8164             mPrivateFlags &= ~MEASURED_DIMENSION_SET;
   8165 
   8166             if (ViewDebug.TRACE_HIERARCHY) {
   8167                 ViewDebug.trace(this, ViewDebug.HierarchyTraceType.ON_MEASURE);
   8168             }
   8169 
   8170             // measure ourselves, this should set the measured dimension flag back
   8171             onMeasure(widthMeasureSpec, heightMeasureSpec);
   8172 
   8173             // flag not set, setMeasuredDimension() was not invoked, we raise
   8174             // an exception to warn the developer
   8175             if ((mPrivateFlags & MEASURED_DIMENSION_SET) != MEASURED_DIMENSION_SET) {
   8176                 throw new IllegalStateException("onMeasure() did not set the"
   8177                         + " measured dimension by calling"
   8178                         + " setMeasuredDimension()");
   8179             }
   8180 
   8181             mPrivateFlags |= LAYOUT_REQUIRED;
   8182         }
   8183 
   8184         mOldWidthMeasureSpec = widthMeasureSpec;
   8185         mOldHeightMeasureSpec = heightMeasureSpec;
   8186     }
   8187 
   8188     /**
   8189      * <p>
   8190      * Measure the view and its content to determine the measured width and the
   8191      * measured height. This method is invoked by {@link #measure(int, int)} and
   8192      * should be overriden by subclasses to provide accurate and efficient
   8193      * measurement of their contents.
   8194      * </p>
   8195      *
   8196      * <p>
   8197      * <strong>CONTRACT:</strong> When overriding this method, you
   8198      * <em>must</em> call {@link #setMeasuredDimension(int, int)} to store the
   8199      * measured width and height of this view. Failure to do so will trigger an
   8200      * <code>IllegalStateException</code>, thrown by
   8201      * {@link #measure(int, int)}. Calling the superclass'
   8202      * {@link #onMeasure(int, int)} is a valid use.
   8203      * </p>
   8204      *
   8205      * <p>
   8206      * The base class implementation of measure defaults to the background size,
   8207      * unless a larger size is allowed by the MeasureSpec. Subclasses should
   8208      * override {@link #onMeasure(int, int)} to provide better measurements of
   8209      * their content.
   8210      * </p>
   8211      *
   8212      * <p>
   8213      * If this method is overridden, it is the subclass's responsibility to make
   8214      * sure the measured height and width are at least the view's minimum height
   8215      * and width ({@link #getSuggestedMinimumHeight()} and
   8216      * {@link #getSuggestedMinimumWidth()}).
   8217      * </p>
   8218      *
   8219      * @param widthMeasureSpec horizontal space requirements as imposed by the parent.
   8220      *                         The requirements are encoded with
   8221      *                         {@link android.view.View.MeasureSpec}.
   8222      * @param heightMeasureSpec vertical space requirements as imposed by the parent.
   8223      *                         The requirements are encoded with
   8224      *                         {@link android.view.View.MeasureSpec}.
   8225      *
   8226      * @see #getMeasuredWidth()
   8227      * @see #getMeasuredHeight()
   8228      * @see #setMeasuredDimension(int, int)
   8229      * @see #getSuggestedMinimumHeight()
   8230      * @see #getSuggestedMinimumWidth()
   8231      * @see android.view.View.MeasureSpec#getMode(int)
   8232      * @see android.view.View.MeasureSpec#getSize(int)
   8233      */
   8234     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
   8235         setMeasuredDimension(getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec),
   8236                 getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec));
   8237     }
   8238 
   8239     /**
   8240      * <p>This mehod must be called by {@link #onMeasure(int, int)} to store the
   8241      * measured width and measured height. Failing to do so will trigger an
   8242      * exception at measurement time.</p>
   8243      *
   8244      * @param measuredWidth the measured width of this view
   8245      * @param measuredHeight the measured height of this view
   8246      */
   8247     protected final void setMeasuredDimension(int measuredWidth, int measuredHeight) {
   8248         mMeasuredWidth = measuredWidth;
   8249         mMeasuredHeight = measuredHeight;
   8250 
   8251         mPrivateFlags |= MEASURED_DIMENSION_SET;
   8252     }
   8253 
   8254     /**
   8255      * Utility to reconcile a desired size with constraints imposed by a MeasureSpec.
   8256      * Will take the desired size, unless a different size is imposed by the constraints.
   8257      *
   8258      * @param size How big the view wants to be
   8259      * @param measureSpec Constraints imposed by the parent
   8260      * @return The size this view should be.
   8261      */
   8262     public static int resolveSize(int size, int measureSpec) {
   8263         int result = size;
   8264         int specMode = MeasureSpec.getMode(measureSpec);
   8265         int specSize =  MeasureSpec.getSize(measureSpec);
   8266         switch (specMode) {
   8267         case MeasureSpec.UNSPECIFIED:
   8268             result = size;
   8269             break;
   8270         case MeasureSpec.AT_MOST:
   8271             result = Math.min(size, specSize);
   8272             break;
   8273         case MeasureSpec.EXACTLY:
   8274             result = specSize;
   8275             break;
   8276         }
   8277         return result;
   8278     }
   8279 
   8280     /**
   8281      * Utility to return a default size. Uses the supplied size if the
   8282      * MeasureSpec imposed no contraints. Will get larger if allowed
   8283      * by the MeasureSpec.
   8284      *
   8285      * @param size Default size for this view
   8286      * @param measureSpec Constraints imposed by the parent
   8287      * @return The size this view should be.
   8288      */
   8289     public static int getDefaultSize(int size, int measureSpec) {
   8290         int result = size;
   8291         int specMode = MeasureSpec.getMode(measureSpec);
   8292         int specSize =  MeasureSpec.getSize(measureSpec);
   8293 
   8294         switch (specMode) {
   8295         case MeasureSpec.UNSPECIFIED:
   8296             result = size;
   8297             break;
   8298         case MeasureSpec.AT_MOST:
   8299         case MeasureSpec.EXACTLY:
   8300             result = specSize;
   8301             break;
   8302         }
   8303         return result;
   8304     }
   8305 
   8306     /**
   8307      * Returns the suggested minimum height that the view should use. This
   8308      * returns the maximum of the view's minimum height
   8309      * and the background's minimum height
   8310      * ({@link android.graphics.drawable.Drawable#getMinimumHeight()}).
   8311      * <p>
   8312      * When being used in {@link #onMeasure(int, int)}, the caller should still
   8313      * ensure the returned height is within the requirements of the parent.
   8314      *
   8315      * @return The suggested minimum height of the view.
   8316      */
   8317     protected int getSuggestedMinimumHeight() {
   8318         int suggestedMinHeight = mMinHeight;
   8319 
   8320         if (mBGDrawable != null) {
   8321             final int bgMinHeight = mBGDrawable.getMinimumHeight();
   8322             if (suggestedMinHeight < bgMinHeight) {
   8323                 suggestedMinHeight = bgMinHeight;
   8324             }
   8325         }
   8326 
   8327         return suggestedMinHeight;
   8328     }
   8329 
   8330     /**
   8331      * Returns the suggested minimum width that the view should use. This
   8332      * returns the maximum of the view's minimum width)
   8333      * and the background's minimum width
   8334      *  ({@link android.graphics.drawable.Drawable#getMinimumWidth()}).
   8335      * <p>
   8336      * When being used in {@link #onMeasure(int, int)}, the caller should still
   8337      * ensure the returned width is within the requirements of the parent.
   8338      *
   8339      * @return The suggested minimum width of the view.
   8340      */
   8341     protected int getSuggestedMinimumWidth() {
   8342         int suggestedMinWidth = mMinWidth;
   8343 
   8344         if (mBGDrawable != null) {
   8345             final int bgMinWidth = mBGDrawable.getMinimumWidth();
   8346             if (suggestedMinWidth < bgMinWidth) {
   8347                 suggestedMinWidth = bgMinWidth;
   8348             }
   8349         }
   8350 
   8351         return suggestedMinWidth;
   8352     }
   8353 
   8354     /**
   8355      * Sets the minimum height of the view. It is not guaranteed the view will
   8356      * be able to achieve this minimum height (for example, if its parent layout
   8357      * constrains it with less available height).
   8358      *
   8359      * @param minHeight The minimum height the view will try to be.
   8360      */
   8361     public void setMinimumHeight(int minHeight) {
   8362         mMinHeight = minHeight;
   8363     }
   8364 
   8365     /**
   8366      * Sets the minimum width of the view. It is not guaranteed the view will
   8367      * be able to achieve this minimum width (for example, if its parent layout
   8368      * constrains it with less available width).
   8369      *
   8370      * @param minWidth The minimum width the view will try to be.
   8371      */
   8372     public void setMinimumWidth(int minWidth) {
   8373         mMinWidth = minWidth;
   8374     }
   8375 
   8376     /**
   8377      * Get the animation currently associated with this view.
   8378      *
   8379      * @return The animation that is currently playing or
   8380      *         scheduled to play for this view.
   8381      */
   8382     public Animation getAnimation() {
   8383         return mCurrentAnimation;
   8384     }
   8385 
   8386     /**
   8387      * Start the specified animation now.
   8388      *
   8389      * @param animation the animation to start now
   8390      */
   8391     public void startAnimation(Animation animation) {
   8392         animation.setStartTime(Animation.START_ON_FIRST_FRAME);
   8393         setAnimation(animation);
   8394         invalidate();
   8395     }
   8396 
   8397     /**
   8398      * Cancels any animations for this view.
   8399      */
   8400     public void clearAnimation() {
   8401         if (mCurrentAnimation != null) {
   8402             mCurrentAnimation.detach();
   8403         }
   8404         mCurrentAnimation = null;
   8405     }
   8406 
   8407     /**
   8408      * Sets the next animation to play for this view.
   8409      * If you want the animation to play immediately, use
   8410      * startAnimation. This method provides allows fine-grained
   8411      * control over the start time and invalidation, but you
   8412      * must make sure that 1) the animation has a start time set, and
   8413      * 2) the view will be invalidated when the animation is supposed to
   8414      * start.
   8415      *
   8416      * @param animation The next animation, or null.
   8417      */
   8418     public void setAnimation(Animation animation) {
   8419         mCurrentAnimation = animation;
   8420         if (animation != null) {
   8421             animation.reset();
   8422         }
   8423     }
   8424 
   8425     /**
   8426      * Invoked by a parent ViewGroup to notify the start of the animation
   8427      * currently associated with this view. If you override this method,
   8428      * always call super.onAnimationStart();
   8429      *
   8430      * @see #setAnimation(android.view.animation.Animation)
   8431      * @see #getAnimation()
   8432      */
   8433     protected void onAnimationStart() {
   8434         mPrivateFlags |= ANIMATION_STARTED;
   8435     }
   8436 
   8437     /**
   8438      * Invoked by a parent ViewGroup to notify the end of the animation
   8439      * currently associated with this view. If you override this method,
   8440      * always call super.onAnimationEnd();
   8441      *
   8442      * @see #setAnimation(android.view.animation.Animation)
   8443      * @see #getAnimation()
   8444      */
   8445     protected void onAnimationEnd() {
   8446         mPrivateFlags &= ~ANIMATION_STARTED;
   8447     }
   8448 
   8449     /**
   8450      * Invoked if there is a Transform that involves alpha. Subclass that can
   8451      * draw themselves with the specified alpha should return true, and then
   8452      * respect that alpha when their onDraw() is called. If this returns false
   8453      * then the view may be redirected to draw into an offscreen buffer to
   8454      * fulfill the request, which will look fine, but may be slower than if the
   8455      * subclass handles it internally. The default implementation returns false.
   8456      *
   8457      * @param alpha The alpha (0..255) to apply to the view's drawing
   8458      * @return true if the view can draw with the specified alpha.
   8459      */
   8460     protected boolean onSetAlpha(int alpha) {
   8461         return false;
   8462     }
   8463 
   8464     /**
   8465      * This is used by the RootView to perform an optimization when
   8466      * the view hierarchy contains one or several SurfaceView.
   8467      * SurfaceView is always considered transparent, but its children are not,
   8468      * therefore all View objects remove themselves from the global transparent
   8469      * region (passed as a parameter to this function).
   8470      *
   8471      * @param region The transparent region for this ViewRoot (window).
   8472      *
   8473      * @return Returns true if the effective visibility of the view at this
   8474      * point is opaque, regardless of the transparent region; returns false
   8475      * if it is possible for underlying windows to be seen behind the view.
   8476      *
   8477      * {@hide}
   8478      */
   8479     public boolean gatherTransparentRegion(Region region) {
   8480         final AttachInfo attachInfo = mAttachInfo;
   8481         if (region != null && attachInfo != null) {
   8482             final int pflags = mPrivateFlags;
   8483             if ((pflags & SKIP_DRAW) == 0) {
   8484                 // The SKIP_DRAW flag IS NOT set, so this view draws. We need to
   8485                 // remove it from the transparent region.
   8486                 final int[] location = attachInfo.mTransparentLocation;
   8487                 getLocationInWindow(location);
   8488                 region.op(location[0], location[1], location[0] + mRight - mLeft,
   8489                         location[1] + mBottom - mTop, Region.Op.DIFFERENCE);
   8490             } else if ((pflags & ONLY_DRAWS_BACKGROUND) != 0 && mBGDrawable != null) {
   8491                 // The ONLY_DRAWS_BACKGROUND flag IS set and the background drawable
   8492                 // exists, so we remove the background drawable's non-transparent
   8493                 // parts from this transparent region.
   8494                 applyDrawableToTransparentRegion(mBGDrawable, region);
   8495             }
   8496         }
   8497         return true;
   8498     }
   8499 
   8500     /**
   8501      * Play a sound effect for this view.
   8502      *
   8503      * <p>The framework will play sound effects for some built in actions, such as
   8504      * clicking, but you may wish to play these effects in your widget,
   8505      * for instance, for internal navigation.
   8506      *
   8507      * <p>The sound effect will only be played if sound effects are enabled by the user, and
   8508      * {@link #isSoundEffectsEnabled()} is true.
   8509      *
   8510      * @param soundConstant One of the constants defined in {@link SoundEffectConstants}
   8511      */
   8512     public void playSoundEffect(int soundConstant) {
   8513         if (mAttachInfo == null || mAttachInfo.mRootCallbacks == null || !isSoundEffectsEnabled()) {
   8514             return;
   8515         }
   8516         mAttachInfo.mRootCallbacks.playSoundEffect(soundConstant);
   8517     }
   8518 
   8519     /**
   8520      * BZZZTT!!1!
   8521      *
   8522      * <p>Provide haptic feedback to the user for this view.
   8523      *
   8524      * <p>The framework will provide haptic feedback for some built in actions,
   8525      * such as long presses, but you may wish to provide feedback for your
   8526      * own widget.
   8527      *
   8528      * <p>The feedback will only be performed if
   8529      * {@link #isHapticFeedbackEnabled()} is true.
   8530      *
   8531      * @param feedbackConstant One of the constants defined in
   8532      * {@link HapticFeedbackConstants}
   8533      */
   8534     public boolean performHapticFeedback(int feedbackConstant) {
   8535         return performHapticFeedback(feedbackConstant, 0);
   8536     }
   8537 
   8538     /**
   8539      * BZZZTT!!1!
   8540      *
   8541      * <p>Like {@link #performHapticFeedback(int)}, with additional options.
   8542      *
   8543      * @param feedbackConstant One of the constants defined in
   8544      * {@link HapticFeedbackConstants}
   8545      * @param flags Additional flags as per {@link HapticFeedbackConstants}.
   8546      */
   8547     public boolean performHapticFeedback(int feedbackConstant, int flags) {
   8548         if (mAttachInfo == null) {
   8549             return false;
   8550         }
   8551         if ((flags&HapticFeedbackConstants.FLAG_IGNORE_VIEW_SETTING) == 0
   8552                 && !isHapticFeedbackEnabled()) {
   8553             return false;
   8554         }
   8555         return mAttachInfo.mRootCallbacks.performHapticFeedback(
   8556                 feedbackConstant,
   8557                 (flags&HapticFeedbackConstants.FLAG_IGNORE_GLOBAL_SETTING) != 0);
   8558     }
   8559 
   8560     /**
   8561      * This needs to be a better API (NOT ON VIEW) before it is exposed.  If
   8562      * it is ever exposed at all.
   8563      * @hide
   8564      */
   8565     public void onCloseSystemDialogs(String reason) {
   8566     }
   8567 
   8568     /**
   8569      * Given a Drawable whose bounds have been set to draw into this view,
   8570      * update a Region being computed for {@link #gatherTransparentRegion} so
   8571      * that any non-transparent parts of the Drawable are removed from the
   8572      * given transparent region.
   8573      *
   8574      * @param dr The Drawable whose transparency is to be applied to the region.
   8575      * @param region A Region holding the current transparency information,
   8576      * where any parts of the region that are set are considered to be
   8577      * transparent.  On return, this region will be modified to have the
   8578      * transparency information reduced by the corresponding parts of the
   8579      * Drawable that are not transparent.
   8580      * {@hide}
   8581      */
   8582     public void applyDrawableToTransparentRegion(Drawable dr, Region region) {
   8583         if (DBG) {
   8584             Log.i("View", "Getting transparent region for: " + this);
   8585         }
   8586         final Region r = dr.getTransparentRegion();
   8587         final Rect db = dr.getBounds();
   8588         final AttachInfo attachInfo = mAttachInfo;
   8589         if (r != null && attachInfo != null) {
   8590             final int w = getRight()-getLeft();
   8591             final int h = getBottom()-getTop();
   8592             if (db.left > 0) {
   8593                 //Log.i("VIEW", "Drawable left " + db.left + " > view 0");
   8594                 r.op(0, 0, db.left, h, Region.Op.UNION);
   8595             }
   8596             if (db.right < w) {
   8597                 //Log.i("VIEW", "Drawable right " + db.right + " < view " + w);
   8598                 r.op(db.right, 0, w, h, Region.Op.UNION);
   8599             }
   8600             if (db.top > 0) {
   8601                 //Log.i("VIEW", "Drawable top " + db.top + " > view 0");
   8602                 r.op(0, 0, w, db.top, Region.Op.UNION);
   8603             }
   8604             if (db.bottom < h) {
   8605                 //Log.i("VIEW", "Drawable bottom " + db.bottom + " < view " + h);
   8606                 r.op(0, db.bottom, w, h, Region.Op.UNION);
   8607             }
   8608             final int[] location = attachInfo.mTransparentLocation;
   8609             getLocationInWindow(location);
   8610             r.translate(location[0], location[1]);
   8611             region.op(r, Region.Op.INTERSECT);
   8612         } else {
   8613             region.op(db, Region.Op.DIFFERENCE);
   8614         }
   8615     }
   8616 
   8617     private void postCheckForLongClick(int delayOffset) {
   8618         mHasPerformedLongPress = false;
   8619 
   8620         if (mPendingCheckForLongPress == null) {
   8621             mPendingCheckForLongPress = new CheckForLongPress();
   8622         }
   8623         mPendingCheckForLongPress.rememberWindowAttachCount();
   8624         postDelayed(mPendingCheckForLongPress,
   8625                 ViewConfiguration.getLongPressTimeout() - delayOffset);
   8626     }
   8627 
   8628     private static int[] stateSetUnion(final int[] stateSet1,
   8629                                        final int[] stateSet2) {
   8630         final int stateSet1Length = stateSet1.length;
   8631         final int stateSet2Length = stateSet2.length;
   8632         final int[] newSet = new int[stateSet1Length + stateSet2Length];
   8633         int k = 0;
   8634         int i = 0;
   8635         int j = 0;
   8636         // This is a merge of the two input state sets and assumes that the
   8637         // input sets are sorted by the order imposed by ViewDrawableStates.
   8638         for (int viewState : R.styleable.ViewDrawableStates) {
   8639             if (i < stateSet1Length && stateSet1[i] == viewState) {
   8640                 newSet[k++] = viewState;
   8641                 i++;
   8642             } else if (j < stateSet2Length && stateSet2[j] == viewState) {
   8643                 newSet[k++] = viewState;
   8644                 j++;
   8645             }
   8646             if (k > 1) {
   8647                 assert(newSet[k - 1] > newSet[k - 2]);
   8648             }
   8649         }
   8650         return newSet;
   8651     }
   8652 
   8653     /**
   8654      * Inflate a view from an XML resource.  This convenience method wraps the {@link
   8655      * LayoutInflater} class, which provides a full range of options for view inflation.
   8656      *
   8657      * @param context The Context object for your activity or application.
   8658      * @param resource The resource ID to inflate
   8659      * @param root A view group that will be the parent.  Used to properly inflate the
   8660      * layout_* parameters.
   8661      * @see LayoutInflater
   8662      */
   8663     public static View inflate(Context context, int resource, ViewGroup root) {
   8664         LayoutInflater factory = LayoutInflater.from(context);
   8665         return factory.inflate(resource, root);
   8666     }
   8667 
   8668     /**
   8669      * A MeasureSpec encapsulates the layout requirements passed from parent to child.
   8670      * Each MeasureSpec represents a requirement for either the width or the height.
   8671      * A MeasureSpec is comprised of a size and a mode. There are three possible
   8672      * modes:
   8673      * <dl>
   8674      * <dt>UNSPECIFIED</dt>
   8675      * <dd>
   8676      * The parent has not imposed any constraint on the child. It can be whatever size
   8677      * it wants.
   8678      * </dd>
   8679      *
   8680      * <dt>EXACTLY</dt>
   8681      * <dd>
   8682      * The parent has determined an exact size for the child. The child is going to be
   8683      * given those bounds regardless of how big it wants to be.
   8684      * </dd>
   8685      *
   8686      * <dt>AT_MOST</dt>
   8687      * <dd>
   8688      * The child can be as large as it wants up to the specified size.
   8689      * </dd>
   8690      * </dl>
   8691      *
   8692      * MeasureSpecs are implemented as ints to reduce object allocation. This class
   8693      * is provided to pack and unpack the &lt;size, mode&gt; tuple into the int.
   8694      */
   8695     public static class MeasureSpec {
   8696         private static final int MODE_SHIFT = 30;
   8697         private static final int MODE_MASK  = 0x3 << MODE_SHIFT;
   8698 
   8699         /**
   8700          * Measure specification mode: The parent has not imposed any constraint
   8701          * on the child. It can be whatever size it wants.
   8702          */
   8703         public static final int UNSPECIFIED = 0 << MODE_SHIFT;
   8704 
   8705         /**
   8706          * Measure specification mode: The parent has determined an exact size
   8707          * for the child. The child is going to be given those bounds regardless
   8708          * of how big it wants to be.
   8709          */
   8710         public static final int EXACTLY     = 1 << MODE_SHIFT;
   8711 
   8712         /**
   8713          * Measure specification mode: The child can be as large as it wants up
   8714          * to the specified size.
   8715          */
   8716         public static final int AT_MOST     = 2 << MODE_SHIFT;
   8717 
   8718         /**
   8719          * Creates a measure specification based on the supplied size and mode.
   8720          *
   8721          * The mode must always be one of the following:
   8722          * <ul>
   8723          *  <li>{@link android.view.View.MeasureSpec#UNSPECIFIED}</li>
   8724          *  <li>{@link android.view.View.MeasureSpec#EXACTLY}</li>
   8725          *  <li>{@link android.view.View.MeasureSpec#AT_MOST}</li>
   8726          * </ul>
   8727          *
   8728          * @param size the size of the measure specification
   8729          * @param mode the mode of the measure specification
   8730          * @return the measure specification based on size and mode
   8731          */
   8732         public static int makeMeasureSpec(int size, int mode) {
   8733             return size + mode;
   8734         }
   8735 
   8736         /**
   8737          * Extracts the mode from the supplied measure specification.
   8738          *
   8739          * @param measureSpec the measure specification to extract the mode from
   8740          * @return {@link android.view.View.MeasureSpec#UNSPECIFIED},
   8741          *         {@link android.view.View.MeasureSpec#AT_MOST} or
   8742          *         {@link android.view.View.MeasureSpec#EXACTLY}
   8743          */
   8744         public static int getMode(int measureSpec) {
   8745             return (measureSpec & MODE_MASK);
   8746         }
   8747 
   8748         /**
   8749          * Extracts the size from the supplied measure specification.
   8750          *
   8751          * @param measureSpec the measure specification to extract the size from
   8752          * @return the size in pixels defined in the supplied measure specification
   8753          */
   8754         public static int getSize(int measureSpec) {
   8755             return (measureSpec & ~MODE_MASK);
   8756         }
   8757 
   8758         /**
   8759          * Returns a String representation of the specified measure
   8760          * specification.
   8761          *
   8762          * @param measureSpec the measure specification to convert to a String
   8763          * @return a String with the following format: "MeasureSpec: MODE SIZE"
   8764          */
   8765         public static String toString(int measureSpec) {
   8766             int mode = getMode(measureSpec);
   8767             int size = getSize(measureSpec);
   8768 
   8769             StringBuilder sb = new StringBuilder("MeasureSpec: ");
   8770 
   8771             if (mode == UNSPECIFIED)
   8772                 sb.append("UNSPECIFIED ");
   8773             else if (mode == EXACTLY)
   8774                 sb.append("EXACTLY ");
   8775             else if (mode == AT_MOST)
   8776                 sb.append("AT_MOST ");
   8777             else
   8778                 sb.append(mode).append(" ");
   8779 
   8780             sb.append(size);
   8781             return sb.toString();
   8782         }
   8783     }
   8784 
   8785     class CheckForLongPress implements Runnable {
   8786 
   8787         private int mOriginalWindowAttachCount;
   8788 
   8789         public void run() {
   8790             if (isPressed() && (mParent != null)
   8791                     && mOriginalWindowAttachCount == mWindowAttachCount) {
   8792                 if (performLongClick()) {
   8793                     mHasPerformedLongPress = true;
   8794                 }
   8795             }
   8796         }
   8797 
   8798         public void rememberWindowAttachCount() {
   8799             mOriginalWindowAttachCount = mWindowAttachCount;
   8800         }
   8801     }
   8802 
   8803     private final class CheckForTap implements Runnable {
   8804         public void run() {
   8805             mPrivateFlags &= ~PREPRESSED;
   8806             mPrivateFlags |= PRESSED;
   8807             refreshDrawableState();
   8808             if ((mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) {
   8809                 postCheckForLongClick(ViewConfiguration.getTapTimeout());
   8810             }
   8811         }
   8812     }
   8813 
   8814     private final class PerformClick implements Runnable {
   8815         public void run() {
   8816             performClick();
   8817         }
   8818     }
   8819 
   8820     /**
   8821      * Interface definition for a callback to be invoked when a key event is
   8822      * dispatched to this view. The callback will be invoked before the key
   8823      * event is given to the view.
   8824      */
   8825     public interface OnKeyListener {
   8826         /**
   8827          * Called when a key is dispatched to a view. This allows listeners to
   8828          * get a chance to respond before the target view.
   8829          *
   8830          * @param v The view the key has been dispatched to.
   8831          * @param keyCode The code for the physical key that was pressed
   8832          * @param event The KeyEvent object containing full information about
   8833          *        the event.
   8834          * @return True if the listener has consumed the event, false otherwise.
   8835          */
   8836         boolean onKey(View v, int keyCode, KeyEvent event);
   8837     }
   8838 
   8839     /**
   8840      * Interface definition for a callback to be invoked when a touch event is
   8841      * dispatched to this view. The callback will be invoked before the touch
   8842      * event is given to the view.
   8843      */
   8844     public interface OnTouchListener {
   8845         /**
   8846          * Called when a touch event is dispatched to a view. This allows listeners to
   8847          * get a chance to respond before the target view.
   8848          *
   8849          * @param v The view the touch event has been dispatched to.
   8850          * @param event The MotionEvent object containing full information about
   8851          *        the event.
   8852          * @return True if the listener has consumed the event, false otherwise.
   8853          */
   8854         boolean onTouch(View v, MotionEvent event);
   8855     }
   8856 
   8857     /**
   8858      * Interface definition for a callback to be invoked when a view has been clicked and held.
   8859      */
   8860     public interface OnLongClickListener {
   8861         /**
   8862          * Called when a view has been clicked and held.
   8863          *
   8864          * @param v The view that was clicked and held.
   8865          *
   8866          * return True if the callback consumed the long click, false otherwise
   8867          */
   8868         boolean onLongClick(View v);
   8869     }
   8870 
   8871     /**
   8872      * Interface definition for a callback to be invoked when the focus state of
   8873      * a view changed.
   8874      */
   8875     public interface OnFocusChangeListener {
   8876         /**
   8877          * Called when the focus state of a view has changed.
   8878          *
   8879          * @param v The view whose state has changed.
   8880          * @param hasFocus The new focus state of v.
   8881          */
   8882         void onFocusChange(View v, boolean hasFocus);
   8883     }
   8884 
   8885     /**
   8886      * Interface definition for a callback to be invoked when a view is clicked.
   8887      */
   8888     public interface OnClickListener {
   8889         /**
   8890          * Called when a view has been clicked.
   8891          *
   8892          * @param v The view that was clicked.
   8893          */
   8894         void onClick(View v);
   8895     }
   8896 
   8897     /**
   8898      * Interface definition for a callback to be invoked when the context menu
   8899      * for this view is being built.
   8900      */
   8901     public interface OnCreateContextMenuListener {
   8902         /**
   8903          * Called when the context menu for this view is being built. It is not
   8904          * safe to hold onto the menu after this method returns.
   8905          *
   8906          * @param menu The context menu that is being built
   8907          * @param v The view for which the context menu is being built
   8908          * @param menuInfo Extra information about the item for which the
   8909          *            context menu should be shown. This information will vary
   8910          *            depending on the class of v.
   8911          */
   8912         void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo);
   8913     }
   8914 
   8915     private final class UnsetPressedState implements Runnable {
   8916         public void run() {
   8917             setPressed(false);
   8918         }
   8919     }
   8920 
   8921     /**
   8922      * Base class for derived classes that want to save and restore their own
   8923      * state in {@link android.view.View#onSaveInstanceState()}.
   8924      */
   8925     public static class BaseSavedState extends AbsSavedState {
   8926         /**
   8927          * Constructor used when reading from a parcel. Reads the state of the superclass.
   8928          *
   8929          * @param source
   8930          */
   8931         public BaseSavedState(Parcel source) {
   8932             super(source);
   8933         }
   8934 
   8935         /**
   8936          * Constructor called by derived classes when creating their SavedState objects
   8937          *
   8938          * @param superState The state of the superclass of this view
   8939          */
   8940         public BaseSavedState(Parcelable superState) {
   8941             super(superState);
   8942         }
   8943 
   8944         public static final Parcelable.Creator<BaseSavedState> CREATOR =
   8945                 new Parcelable.Creator<BaseSavedState>() {
   8946             public BaseSavedState createFromParcel(Parcel in) {
   8947                 return new BaseSavedState(in);
   8948             }
   8949 
   8950             public BaseSavedState[] newArray(int size) {
   8951                 return new BaseSavedState[size];
   8952             }
   8953         };
   8954     }
   8955 
   8956     /**
   8957      * A set of information given to a view when it is attached to its parent
   8958      * window.
   8959      */
   8960     static class AttachInfo {
   8961         interface Callbacks {
   8962             void playSoundEffect(int effectId);
   8963             boolean performHapticFeedback(int effectId, boolean always);
   8964         }
   8965 
   8966         /**
   8967          * InvalidateInfo is used to post invalidate(int, int, int, int) messages
   8968          * to a Handler. This class contains the target (View) to invalidate and
   8969          * the coordinates of the dirty rectangle.
   8970          *
   8971          * For performance purposes, this class also implements a pool of up to
   8972          * POOL_LIMIT objects that get reused. This reduces memory allocations
   8973          * whenever possible.
   8974          */
   8975         static class InvalidateInfo implements Poolable<InvalidateInfo> {
   8976             private static final int POOL_LIMIT = 10;
   8977             private static final Pool<InvalidateInfo> sPool = Pools.synchronizedPool(
   8978                     Pools.finitePool(new PoolableManager<InvalidateInfo>() {
   8979                         public InvalidateInfo newInstance() {
   8980                             return new InvalidateInfo();
   8981                         }
   8982 
   8983                         public void onAcquired(InvalidateInfo element) {
   8984                         }
   8985 
   8986                         public void onReleased(InvalidateInfo element) {
   8987                         }
   8988                     }, POOL_LIMIT)
   8989             );
   8990 
   8991             private InvalidateInfo mNext;
   8992 
   8993             View target;
   8994 
   8995             int left;
   8996             int top;
   8997             int right;
   8998             int bottom;
   8999 
   9000             public void setNextPoolable(InvalidateInfo element) {
   9001                 mNext = element;
   9002             }
   9003 
   9004             public InvalidateInfo getNextPoolable() {
   9005                 return mNext;
   9006             }
   9007 
   9008             static InvalidateInfo acquire() {
   9009                 return sPool.acquire();
   9010             }
   9011 
   9012             void release() {
   9013                 sPool.release(this);
   9014             }
   9015         }
   9016 
   9017         final IWindowSession mSession;
   9018 
   9019         final IWindow mWindow;
   9020 
   9021         final IBinder mWindowToken;
   9022 
   9023         final Callbacks mRootCallbacks;
   9024 
   9025         /**
   9026          * The top view of the hierarchy.
   9027          */
   9028         View mRootView;
   9029 
   9030         IBinder mPanelParentWindowToken;
   9031         Surface mSurface;
   9032 
   9033         /**
   9034          * Scale factor used by the compatibility mode
   9035          */
   9036         float mApplicationScale;
   9037 
   9038         /**
   9039          * Indicates whether the application is in compatibility mode
   9040          */
   9041         boolean mScalingRequired;
   9042 
   9043         /**
   9044          * Left position of this view's window
   9045          */
   9046         int mWindowLeft;
   9047 
   9048         /**
   9049          * Top position of this view's window
   9050          */
   9051         int mWindowTop;
   9052 
   9053         /**
   9054          * Indicates whether the window is translucent/transparent
   9055          */
   9056         boolean mTranslucentWindow;
   9057 
   9058         /**
   9059          * For windows that are full-screen but using insets to layout inside
   9060          * of the screen decorations, these are the current insets for the
   9061          * content of the window.
   9062          */
   9063         final Rect mContentInsets = new Rect();
   9064 
   9065         /**
   9066          * For windows that are full-screen but using insets to layout inside
   9067          * of the screen decorations, these are the current insets for the
   9068          * actual visible parts of the window.
   9069          */
   9070         final Rect mVisibleInsets = new Rect();
   9071 
   9072         /**
   9073          * The internal insets given by this window.  This value is
   9074          * supplied by the client (through
   9075          * {@link ViewTreeObserver.OnComputeInternalInsetsListener}) and will
   9076          * be given to the window manager when changed to be used in laying
   9077          * out windows behind it.
   9078          */
   9079         final ViewTreeObserver.InternalInsetsInfo mGivenInternalInsets
   9080                 = new ViewTreeObserver.InternalInsetsInfo();
   9081 
   9082         /**
   9083          * All views in the window's hierarchy that serve as scroll containers,
   9084          * used to determine if the window can be resized or must be panned
   9085          * to adjust for a soft input area.
   9086          */
   9087         final ArrayList<View> mScrollContainers = new ArrayList<View>();
   9088 
   9089         final KeyEvent.DispatcherState mKeyDispatchState
   9090                 = new KeyEvent.DispatcherState();
   9091 
   9092         /**
   9093          * Indicates whether the view's window currently has the focus.
   9094          */
   9095         boolean mHasWindowFocus;
   9096 
   9097         /**
   9098          * The current visibility of the window.
   9099          */
   9100         int mWindowVisibility;
   9101 
   9102         /**
   9103          * Indicates the time at which drawing started to occur.
   9104          */
   9105         long mDrawingTime;
   9106 
   9107         /**
   9108          * Indicates whether or not ignoring the DIRTY_MASK flags.
   9109          */
   9110         boolean mIgnoreDirtyState;
   9111 
   9112         /**
   9113          * Indicates whether the view's window is currently in touch mode.
   9114          */
   9115         boolean mInTouchMode;
   9116 
   9117         /**
   9118          * Indicates that ViewRoot should trigger a global layout change
   9119          * the next time it performs a traversal
   9120          */
   9121         boolean mRecomputeGlobalAttributes;
   9122 
   9123         /**
   9124          * Set during a traveral if any views want to keep the screen on.
   9125          */
   9126         boolean mKeepScreenOn;
   9127 
   9128         /**
   9129          * Set if the visibility of any views has changed.
   9130          */
   9131         boolean mViewVisibilityChanged;
   9132 
   9133         /**
   9134          * Set to true if a view has been scrolled.
   9135          */
   9136         boolean mViewScrollChanged;
   9137 
   9138         /**
   9139          * Global to the view hierarchy used as a temporary for dealing with
   9140          * x/y points in the transparent region computations.
   9141          */
   9142         final int[] mTransparentLocation = new int[2];
   9143 
   9144         /**
   9145          * Global to the view hierarchy used as a temporary for dealing with
   9146          * x/y points in the ViewGroup.invalidateChild implementation.
   9147          */
   9148         final int[] mInvalidateChildLocation = new int[2];
   9149 
   9150         /**
   9151          * The view tree observer used to dispatch global events like
   9152          * layout, pre-draw, touch mode change, etc.
   9153          */
   9154         final ViewTreeObserver mTreeObserver = new ViewTreeObserver();
   9155 
   9156         /**
   9157          * A Canvas used by the view hierarchy to perform bitmap caching.
   9158          */
   9159         Canvas mCanvas;
   9160 
   9161         /**
   9162          * A Handler supplied by a view's {@link android.view.ViewRoot}. This
   9163          * handler can be used to pump events in the UI events queue.
   9164          */
   9165         final Handler mHandler;
   9166 
   9167         /**
   9168          * Identifier for messages requesting the view to be invalidated.
   9169          * Such messages should be sent to {@link #mHandler}.
   9170          */
   9171         static final int INVALIDATE_MSG = 0x1;
   9172 
   9173         /**
   9174          * Identifier for messages requesting the view to invalidate a region.
   9175          * Such messages should be sent to {@link #mHandler}.
   9176          */
   9177         static final int INVALIDATE_RECT_MSG = 0x2;
   9178 
   9179         /**
   9180          * Temporary for use in computing invalidate rectangles while
   9181          * calling up the hierarchy.
   9182          */
   9183         final Rect mTmpInvalRect = new Rect();
   9184 
   9185         /**
   9186          * Temporary list for use in collecting focusable descendents of a view.
   9187          */
   9188         final ArrayList<View> mFocusablesTempList = new ArrayList<View>(24);
   9189 
   9190         /**
   9191          * Creates a new set of attachment information with the specified
   9192          * events handler and thread.
   9193          *
   9194          * @param handler the events handler the view must use
   9195          */
   9196         AttachInfo(IWindowSession session, IWindow window,
   9197                 Handler handler, Callbacks effectPlayer) {
   9198             mSession = session;
   9199             mWindow = window;
   9200             mWindowToken = window.asBinder();
   9201             mHandler = handler;
   9202             mRootCallbacks = effectPlayer;
   9203         }
   9204     }
   9205 
   9206     /**
   9207      * <p>ScrollabilityCache holds various fields used by a View when scrolling
   9208      * is supported. This avoids keeping too many unused fields in most
   9209      * instances of View.</p>
   9210      */
   9211     private static class ScrollabilityCache implements Runnable {
   9212 
   9213         /**
   9214          * Scrollbars are not visible
   9215          */
   9216         public static final int OFF = 0;
   9217 
   9218         /**
   9219          * Scrollbars are visible
   9220          */
   9221         public static final int ON = 1;
   9222 
   9223         /**
   9224          * Scrollbars are fading away
   9225          */
   9226         public static final int FADING = 2;
   9227 
   9228         public boolean fadeScrollBars;
   9229 
   9230         public int fadingEdgeLength;
   9231         public int scrollBarDefaultDelayBeforeFade;
   9232         public int scrollBarFadeDuration;
   9233 
   9234         public int scrollBarSize;
   9235         public ScrollBarDrawable scrollBar;
   9236         public float[] interpolatorValues;
   9237         public View host;
   9238 
   9239         public final Paint paint;
   9240         public final Matrix matrix;
   9241         public Shader shader;
   9242 
   9243         public final Interpolator scrollBarInterpolator = new Interpolator(1, 2);
   9244 
   9245         private final float[] mOpaque = {255.0f};
   9246         private final float[] mTransparent = {0.0f};
   9247 
   9248         /**
   9249          * When fading should start. This time moves into the future every time
   9250          * a new scroll happens. Measured based on SystemClock.uptimeMillis()
   9251          */
   9252         public long fadeStartTime;
   9253 
   9254 
   9255         /**
   9256          * The current state of the scrollbars: ON, OFF, or FADING
   9257          */
   9258         public int state = OFF;
   9259 
   9260         private int mLastColor;
   9261 
   9262         public ScrollabilityCache(ViewConfiguration configuration, View host) {
   9263             fadingEdgeLength = configuration.getScaledFadingEdgeLength();
   9264             scrollBarSize = configuration.getScaledScrollBarSize();
   9265             scrollBarDefaultDelayBeforeFade = ViewConfiguration.getScrollDefaultDelay();
   9266             scrollBarFadeDuration = ViewConfiguration.getScrollBarFadeDuration();
   9267 
   9268             paint = new Paint();
   9269             matrix = new Matrix();
   9270             // use use a height of 1, and then wack the matrix each time we
   9271             // actually use it.
   9272             shader = new LinearGradient(0, 0, 0, 1, 0xFF000000, 0, Shader.TileMode.CLAMP);
   9273 
   9274             paint.setShader(shader);
   9275             paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
   9276             this.host = host;
   9277         }
   9278 
   9279         public void setFadeColor(int color) {
   9280             if (color != 0 && color != mLastColor) {
   9281                 mLastColor = color;
   9282                 color |= 0xFF000000;
   9283 
   9284                 shader = new LinearGradient(0, 0, 0, 1, color | 0xFF000000,
   9285                         color & 0x00FFFFFF, Shader.TileMode.CLAMP);
   9286 
   9287                 paint.setShader(shader);
   9288                 // Restore the default transfer mode (src_over)
   9289                 paint.setXfermode(null);
   9290             }
   9291         }
   9292 
   9293         public void run() {
   9294             long now = AnimationUtils.currentAnimationTimeMillis();
   9295             if (now >= fadeStartTime) {
   9296 
   9297                 // the animation fades the scrollbars out by changing
   9298                 // the opacity (alpha) from fully opaque to fully
   9299                 // transparent
   9300                 int nextFrame = (int) now;
   9301                 int framesCount = 0;
   9302 
   9303                 Interpolator interpolator = scrollBarInterpolator;
   9304 
   9305                 // Start opaque
   9306                 interpolator.setKeyFrame(framesCount++, nextFrame, mOpaque);
   9307 
   9308                 // End transparent
   9309                 nextFrame += scrollBarFadeDuration;
   9310                 interpolator.setKeyFrame(framesCount, nextFrame, mTransparent);
   9311 
   9312                 state = FADING;
   9313 
   9314                 // Kick off the fade animation
   9315                 host.invalidate();
   9316             }
   9317         }
   9318 
   9319     }
   9320 }
   9321