xref: /frameworks/base/core/java/android/view/View.java

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.view;

import com.android.internal.R;
import com.android.internal.view.menu.MenuBuilder;

import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Interpolator;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Point;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.Region;
import android.graphics.Shader;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Parcel;
import android.os.Parcelable;
import android.os.RemoteException;
import android.os.SystemClock;
import android.os.SystemProperties;
import android.util.AttributeSet;
import android.util.Config;
import android.util.EventLog;
import android.util.Log;
import android.util.Pool;
import android.util.Poolable;
import android.util.PoolableManager;
import android.util.Pools;
import android.util.SparseArray;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityEventSource;
import android.view.accessibility.AccessibilityManager;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputConnection;
import android.view.inputmethod.InputMethodManager;
import android.widget.ScrollBarDrawable;

import java.lang.ref.SoftReference;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.WeakHashMap;

/**
 * <p>
 * This class represents the basic building block for user interface components. A View
 * occupies a rectangular area on the screen and is responsible for drawing and
 * event handling. View is the base class for <em>widgets</em>, which are
 * used to create interactive UI components (buttons, text fields, etc.). The
 * {@link android.view.ViewGroup} subclass is the base class for <em>layouts</em>, which
 * are invisible containers that hold other Views (or other ViewGroups) and define
 * their layout properties.
 * </p>
 *
 * <div class="special">
 * <p>For an introduction to using this class to develop your
 * application's user interface, read the Developer Guide documentation on
 * <strong><a href="{@docRoot}guide/topics/ui/index.html">User Interface</a></strong>. Special topics
 * include:
 * <br/><a href="{@docRoot}guide/topics/ui/declaring-layout.html">Declaring Layout</a>
 * <br/><a href="{@docRoot}guide/topics/ui/menus.html">Creating Menus</a>
 * <br/><a href="{@docRoot}guide/topics/ui/layout-objects.html">Common Layout Objects</a>
 * <br/><a href="{@docRoot}guide/topics/ui/binding.html">Binding to Data with AdapterView</a>
 * <br/><a href="{@docRoot}guide/topics/ui/ui-events.html">Handling UI Events</a>
 * <br/><a href="{@docRoot}guide/topics/ui/themes.html">Applying Styles and Themes</a>
 * <br/><a href="{@docRoot}guide/topics/ui/custom-components.html">Building Custom Components</a>
 * <br/><a href="{@docRoot}guide/topics/ui/how-android-draws.html">How Android Draws Views</a>.
 * </p>
 * </div>
 *
 * <a name="Using"></a>
 * <h3>Using Views</h3>
 * <p>
 * All of the views in a window are arranged in a single tree. You can add views
 * either from code or by specifying a tree of views in one or more XML layout
 * files. There are many specialized subclasses of views that act as controls or
 * are capable of displaying text, images, or other content.
 * </p>
 * <p>
 * Once you have created a tree of views, there are typically a few types of
 * common operations you may wish to perform:
 * <ul>
 * <li><strong>Set properties:</strong> for example setting the text of a
 * {@link android.widget.TextView}. The available properties and the methods
 * that set them will vary among the different subclasses of views. Note that
 * properties that are known at build time can be set in the XML layout
 * files.</li>
 * <li><strong>Set focus:</strong> The framework will handled moving focus in
 * response to user input. To force focus to a specific view, call
 * {@link #requestFocus}.</li>
 * <li><strong>Set up listeners:</strong> Views allow clients to set listeners
 * that will be notified when something interesting happens to the view. For
 * example, all views will let you set a listener to be notified when the view
 * gains or loses focus. You can register such a listener using
 * {@link #setOnFocusChangeListener}. Other view subclasses offer more
 * specialized listeners. For example, a Button exposes a listener to notify
 * clients when the button is clicked.</li>
 * <li><strong>Set visibility:</strong> You can hide or show views using
 * {@link #setVisibility}.</li>
 * </ul>
 * </p>
 * <p><em>
 * Note: The Android framework is responsible for measuring, laying out and
 * drawing views. You should not call methods that perform these actions on
 * views yourself unless you are actually implementing a
 * {@link android.view.ViewGroup}.
 * </em></p>
 *
 * <a name="Lifecycle"></a>
 * <h3>Implementing a Custom View</h3>
 *
 * <p>
 * To implement a custom view, you will usually begin by providing overrides for
 * some of the standard methods that the framework calls on all views. You do
 * not need to override all of these methods. In fact, you can start by just
 * overriding {@link #onDraw(android.graphics.Canvas)}.
 * <table border="2" width="85%" align="center" cellpadding="5">
 *     <thead>
 *         <tr><th>Category</th> <th>Methods</th> <th>Description</th></tr>
 *     </thead>
 *
 *     <tbody>
 *     <tr>
 *         <td rowspan="2">Creation</td>
 *         <td>Constructors</td>
 *         <td>There is a form of the constructor that are called when the view
 *         is created from code and a form that is called when the view is
 *         inflated from a layout file. The second form should parse and apply
 *         any attributes defined in the layout file.
 *         </td>
 *     </tr>
 *     <tr>
 *         <td><code>{@link #onFinishInflate()}</code></td>
 *         <td>Called after a view and all of its children has been inflated
 *         from XML.</td>
 *     </tr>
 *
 *     <tr>
 *         <td rowspan="3">Layout</td>
 *         <td><code>{@link #onMeasure}</code></td>
 *         <td>Called to determine the size requirements for this view and all
 *         of its children.
 *         </td>
 *     </tr>
 *     <tr>
 *         <td><code>{@link #onLayout}</code></td>
 *         <td>Called when this view should assign a size and position to all
 *         of its children.
 *         </td>
 *     </tr>
 *     <tr>
 *         <td><code>{@link #onSizeChanged}</code></td>
 *         <td>Called when the size of this view has changed.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td>Drawing</td>
 *         <td><code>{@link #onDraw}</code></td>
 *         <td>Called when the view should render its content.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td rowspan="4">Event processing</td>
 *         <td><code>{@link #onKeyDown}</code></td>
 *         <td>Called when a new key event occurs.
 *         </td>
 *     </tr>
 *     <tr>
 *         <td><code>{@link #onKeyUp}</code></td>
 *         <td>Called when a key up event occurs.
 *         </td>
 *     </tr>
 *     <tr>
 *         <td><code>{@link #onTrackballEvent}</code></td>
 *         <td>Called when a trackball motion event occurs.
 *         </td>
 *     </tr>
 *     <tr>
 *         <td><code>{@link #onTouchEvent}</code></td>
 *         <td>Called when a touch screen motion event occurs.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td rowspan="2">Focus</td>
 *         <td><code>{@link #onFocusChanged}</code></td>
 *         <td>Called when the view gains or loses focus.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td><code>{@link #onWindowFocusChanged}</code></td>
 *         <td>Called when the window containing the view gains or loses focus.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td rowspan="3">Attaching</td>
 *         <td><code>{@link #onAttachedToWindow()}</code></td>
 *         <td>Called when the view is attached to a window.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td><code>{@link #onDetachedFromWindow}</code></td>
 *         <td>Called when the view is detached from its window.
 *         </td>
 *     </tr>
 *
 *     <tr>
 *         <td><code>{@link #onWindowVisibilityChanged}</code></td>
 *         <td>Called when the visibility of the window containing the view
 *         has changed.
 *         </td>
 *     </tr>
 *     </tbody>
 *
 * </table>
 * </p>
 *
 * <a name="IDs"></a>
 * <h3>IDs</h3>
 * Views may have an integer id associated with them. These ids are typically
 * assigned in the layout XML files, and are used to find specific views within
 * the view tree. A common pattern is to:
 * <ul>
 * <li>Define a Button in the layout file and assign it a unique ID.
 * <pre>
 * &lt;Button id="@+id/my_button"
 *     android:layout_width="wrap_content"
 *     android:layout_height="wrap_content"
 *     android:text="@string/my_button_text"/&gt;
 * </pre></li>
 * <li>From the onCreate method of an Activity, find the Button
 * <pre class="prettyprint">
 *      Button myButton = (Button) findViewById(R.id.my_button);
 * </pre></li>
 * </ul>
 * <p>
 * View IDs need not be unique throughout the tree, but it is good practice to
 * ensure that they are at least unique within the part of the tree you are
 * searching.
 * </p>
 *
 * <a name="Position"></a>
 * <h3>Position</h3>
 * <p>
 * The geometry of a view is that of a rectangle. A view has a location,
 * expressed as a pair of <em>left</em> and <em>top</em> coordinates, and
 * two dimensions, expressed as a width and a height. The unit for location
 * and dimensions is the pixel.
 * </p>
 *
 * <p>
 * It is possible to retrieve the location of a view by invoking the methods
 * {@link #getLeft()} and {@link #getTop()}. The former returns the left, or X,
 * coordinate of the rectangle representing the view. The latter returns the
 * top, or Y, coordinate of the rectangle representing the view. These methods
 * both return the location of the view relative to its parent. For instance,
 * when getLeft() returns 20, that means the view is located 20 pixels to the
 * right of the left edge of its direct parent.
 * </p>
 *
 * <p>
 * In addition, several convenience methods are offered to avoid unnecessary
 * computations, namely {@link #getRight()} and {@link #getBottom()}.
 * These methods return the coordinates of the right and bottom edges of the
 * rectangle representing the view. For instance, calling {@link #getRight()}
 * is similar to the following computation: <code>getLeft() + getWidth()</code>
 * (see <a href="#SizePaddingMargins">Size</a> for more information about the width.)
 * </p>
 *
 * <a name="SizePaddingMargins"></a>
 * <h3>Size, padding and margins</h3>
 * <p>
 * The size of a view is expressed with a width and a height. A view actually
 * possess two pairs of width and height values.
 * </p>
 *
 * <p>
 * The first pair is known as <em>measured width</em> and
 * <em>measured height</em>. These dimensions define how big a view wants to be
 * within its parent (see <a href="#Layout">Layout</a> for more details.) The
 * measured dimensions can be obtained by calling {@link #getMeasuredWidth()}
 * and {@link #getMeasuredHeight()}.
 * </p>
 *
 * <p>
 * The second pair is simply known as <em>width</em> and <em>height</em>, or
 * sometimes <em>drawing width</em> and <em>drawing height</em>. These
 * dimensions define the actual size of the view on screen, at drawing time and
 * after layout. These values may, but do not have to, be different from the
 * measured width and height. The width and height can be obtained by calling
 * {@link #getWidth()} and {@link #getHeight()}.
 * </p>
 *
 * <p>
 * To measure its dimensions, a view takes into account its padding. The padding
 * is expressed in pixels for the left, top, right and bottom parts of the view.
 * Padding can be used to offset the content of the view by a specific amount of
 * pixels. For instance, a left padding of 2 will push the view's content by
 * 2 pixels to the right of the left edge. Padding can be set using the
 * {@link #setPadding(int, int, int, int)} method and queried by calling
 * {@link #getPaddingLeft()}, {@link #getPaddingTop()},
 * {@link #getPaddingRight()} and {@link #getPaddingBottom()}.
 * </p>
 *
 * <p>
 * Even though a view can define a padding, it does not provide any support for
 * margins. However, view groups provide such a support. Refer to
 * {@link android.view.ViewGroup} and
 * {@link android.view.ViewGroup.MarginLayoutParams} for further information.
 * </p>
 *
 * <a name="Layout"></a>
 * <h3>Layout</h3>
 * <p>
 * Layout is a two pass process: a measure pass and a layout pass. The measuring
 * pass is implemented in {@link #measure(int, int)} and is a top-down traversal
 * of the view tree. Each view pushes dimension specifications down the tree
 * during the recursion. At the end of the measure pass, every view has stored
 * its measurements. The second pass happens in
 * {@link #layout(int,int,int,int)} and is also top-down. During
 * this pass each parent is responsible for positioning all of its children
 * using the sizes computed in the measure pass.
 * </p>
 *
 * <p>
 * When a view's measure() method returns, its {@link #getMeasuredWidth()} and
 * {@link #getMeasuredHeight()} values must be set, along with those for all of
 * that view's descendants. A view's measured width and measured height values
 * must respect the constraints imposed by the view's parents. This guarantees
 * that at the end of the measure pass, all parents accept all of their
 * children's measurements. A parent view may call measure() more than once on
 * its children. For example, the parent may measure each child once with
 * unspecified dimensions to find out how big they want to be, then call
 * measure() on them again with actual numbers if the sum of all the children's
 * unconstrained sizes is too big or too small.
 * </p>
 *
 * <p>
 * The measure pass uses two classes to communicate dimensions. The
 * {@link MeasureSpec} class is used by views to tell their parents how they
 * want to be measured and positioned. The base LayoutParams class just
 * describes how big the view wants to be for both width and height. For each
 * dimension, it can specify one of:
 * <ul>
 * <li> an exact number
 * <li>MATCH_PARENT, which means the view wants to be as big as its parent
 * (minus padding)
 * <li> WRAP_CONTENT, which means that the view wants to be just big enough to
 * enclose its content (plus padding).
 * </ul>
 * There are subclasses of LayoutParams for different subclasses of ViewGroup.
 * For example, AbsoluteLayout has its own subclass of LayoutParams which adds
 * an X and Y value.
 * </p>
 *
 * <p>
 * MeasureSpecs are used to push requirements down the tree from parent to
 * child. A MeasureSpec can be in one of three modes:
 * <ul>
 * <li>UNSPECIFIED: This is used by a parent to determine the desired dimension
 * of a child view. For example, a LinearLayout may call measure() on its child
 * with the height set to UNSPECIFIED and a width of EXACTLY 240 to find out how
 * tall the child view wants to be given a width of 240 pixels.
 * <li>EXACTLY: This is used by the parent to impose an exact size on the
 * child. The child must use this size, and guarantee that all of its
 * descendants will fit within this size.
 * <li>AT_MOST: This is used by the parent to impose a maximum size on the
 * child. The child must gurantee that it and all of its descendants will fit
 * within this size.
 * </ul>
 * </p>
 *
 * <p>
 * To intiate a layout, call {@link #requestLayout}. This method is typically
 * called by a view on itself when it believes that is can no longer fit within
 * its current bounds.
 * </p>
 *
 * <a name="Drawing"></a>
 * <h3>Drawing</h3>
 * <p>
 * Drawing is handled by walking the tree and rendering each view that
 * intersects the the invalid region. Because the tree is traversed in-order,
 * this means that parents will draw before (i.e., behind) their children, with
 * siblings drawn in the order they appear in the tree.
 * If you set a background drawable for a View, then the View will draw it for you
 * before calling back to its <code>onDraw()</code> method.
 * </p>
 *
 * <p>
 * Note that the framework will not draw views that are not in the invalid region.
 * </p>
 *
 * <p>
 * To force a view to draw, call {@link #invalidate()}.
 * </p>
 *
 * <a name="EventHandlingThreading"></a>
 * <h3>Event Handling and Threading</h3>
 * <p>
 * The basic cycle of a view is as follows:
 * <ol>
 * <li>An event comes in and is dispatched to the appropriate view. The view
 * handles the event and notifies any listeners.</li>
 * <li>If in the course of processing the event, the view's bounds may need
 * to be changed, the view will call {@link #requestLayout()}.</li>
 * <li>Similarly, if in the course of processing the event the view's appearance
 * may need to be changed, the view will call {@link #invalidate()}.</li>
 * <li>If either {@link #requestLayout()} or {@link #invalidate()} were called,
 * the framework will take care of measuring, laying out, and drawing the tree
 * as appropriate.</li>
 * </ol>
 * </p>
 *
 * <p><em>Note: The entire view tree is single threaded. You must always be on
 * the UI thread when calling any method on any view.</em>
 * If you are doing work on other threads and want to update the state of a view
 * from that thread, you should use a {@link Handler}.
 * </p>
 *
 * <a name="FocusHandling"></a>
 * <h3>Focus Handling</h3>
 * <p>
 * The framework will handle routine focus movement in response to user input.
 * This includes changing the focus as views are removed or hidden, or as new
 * views become available. Views indicate their willingness to take focus
 * through the {@link #isFocusable} method. To change whether a view can take
 * focus, call {@link #setFocusable(boolean)}.  When in touch mode (see notes below)
 * views indicate whether they still would like focus via {@link #isFocusableInTouchMode}
 * and can change this via {@link #setFocusableInTouchMode(boolean)}.
 * </p>
 * <p>
 * Focus movement is based on an algorithm which finds the nearest neighbor in a
 * given direction. In rare cases, the default algorithm may not match the
 * intended behavior of the developer. In these situations, you can provide
 * explicit overrides by using these XML attributes in the layout file:
 * <pre>
 * nextFocusDown
 * nextFocusLeft
 * nextFocusRight
 * nextFocusUp
 * </pre>
 * </p>
 *
 *
 * <p>
 * To get a particular view to take focus, call {@link #requestFocus()}.
 * </p>
 *
 * <a name="TouchMode"></a>
 * <h3>Touch Mode</h3>
 * <p>
 * When a user is navigating a user interface via directional keys such as a D-pad, it is
 * necessary to give focus to actionable items such as buttons so the user can see
 * what will take input.  If the device has touch capabilities, however, and the user
 * begins interacting with the interface by touching it, it is no longer necessary to
 * always highlight, or give focus to, a particular view.  This motivates a mode
 * for interaction named 'touch mode'.
 * </p>
 * <p>
 * For a touch capable device, once the user touches the screen, the device
 * will enter touch mode.  From this point onward, only views for which
 * {@link #isFocusableInTouchMode} is true will be focusable, such as text editing widgets.
 * Other views that are touchable, like buttons, will not take focus when touched; they will
 * only fire the on click listeners.
 * </p>
 * <p>
 * Any time a user hits a directional key, such as a D-pad direction, the view device will
 * exit touch mode, and find a view to take focus, so that the user may resume interacting
 * with the user interface without touching the screen again.
 * </p>
 * <p>
 * The touch mode state is maintained across {@link android.app.Activity}s.  Call
 * {@link #isInTouchMode} to see whether the device is currently in touch mode.
 * </p>
 *
 * <a name="Scrolling"></a>
 * <h3>Scrolling</h3>
 * <p>
 * The framework provides basic support for views that wish to internally
 * scroll their content. This includes keeping track of the X and Y scroll
 * offset as well as mechanisms for drawing scrollbars. See
 * {@link #scrollBy(int, int)}, {@link #scrollTo(int, int)}, and
 * {@link #awakenScrollBars()} for more details.
 * </p>
 *
 * <a name="Tags"></a>
 * <h3>Tags</h3>
 * <p>
 * Unlike IDs, tags are not used to identify views. Tags are essentially an
 * extra piece of information that can be associated with a view. They are most
 * often used as a convenience to store data related to views in the views
 * themselves rather than by putting them in a separate structure.
 * </p>
 *
 * <a name="Animation"></a>
 * <h3>Animation</h3>
 * <p>
 * You can attach an {@link Animation} object to a view using
 * {@link #setAnimation(Animation)} or
 * {@link #startAnimation(Animation)}. The animation can alter the scale,
 * rotation, translation and alpha of a view over time. If the animation is
 * attached to a view that has children, the animation will affect the entire
 * subtree rooted by that node. When an animation is started, the framework will
 * take care of redrawing the appropriate views until the animation completes.
 * </p>
 *
 * <a name="Security"></a>
 * <h3>Security</h3>
 * <p>
 * Sometimes it is essential that an application be able to verify that an action
 * is being performed with the full knowledge and consent of the user, such as
 * granting a permission request, making a purchase or clicking on an advertisement.
 * Unfortunately, a malicious application could try to spoof the user into
 * performing these actions, unaware, by concealing the intended purpose of the view.
 * As a remedy, the framework offers a touch filtering mechanism that can be used to
 * improve the security of views that provide access to sensitive functionality.
 * </p><p>
 * To enable touch filtering, call {@link #setFilterTouchesWhenObscured} or set the
 * andoird:filterTouchesWhenObscured attribute to true.  When enabled, the framework
 * will discard touches that are received whenever the view's window is obscured by
 * another visible window.  As a result, the view will not receive touches whenever a
 * toast, dialog or other window appears above the view's window.
 * </p><p>
 * For more fine-grained control over security, consider overriding the
 * {@link #onFilterTouchEventForSecurity} method to implement your own security policy.
 * See also {@link MotionEvent#FLAG_WINDOW_IS_OBSCURED}.
 * </p>
 *
 * @attr ref android.R.styleable#View_background
 * @attr ref android.R.styleable#View_clickable
 * @attr ref android.R.styleable#View_contentDescription
 * @attr ref android.R.styleable#View_drawingCacheQuality
 * @attr ref android.R.styleable#View_duplicateParentState
 * @attr ref android.R.styleable#View_id
 * @attr ref android.R.styleable#View_fadingEdge
 * @attr ref android.R.styleable#View_fadingEdgeLength
 * @attr ref android.R.styleable#View_filterTouchesWhenObscured
 * @attr ref android.R.styleable#View_fitsSystemWindows
 * @attr ref android.R.styleable#View_isScrollContainer
 * @attr ref android.R.styleable#View_focusable
 * @attr ref android.R.styleable#View_focusableInTouchMode
 * @attr ref android.R.styleable#View_hapticFeedbackEnabled
 * @attr ref android.R.styleable#View_keepScreenOn
 * @attr ref android.R.styleable#View_longClickable
 * @attr ref android.R.styleable#View_minHeight
 * @attr ref android.R.styleable#View_minWidth
 * @attr ref android.R.styleable#View_nextFocusDown
 * @attr ref android.R.styleable#View_nextFocusLeft
 * @attr ref android.R.styleable#View_nextFocusRight
 * @attr ref android.R.styleable#View_nextFocusUp
 * @attr ref android.R.styleable#View_onClick
 * @attr ref android.R.styleable#View_padding
 * @attr ref android.R.styleable#View_paddingBottom
 * @attr ref android.R.styleable#View_paddingLeft
 * @attr ref android.R.styleable#View_paddingRight
 * @attr ref android.R.styleable#View_paddingTop
 * @attr ref android.R.styleable#View_saveEnabled
 * @attr ref android.R.styleable#View_scrollX
 * @attr ref android.R.styleable#View_scrollY
 * @attr ref android.R.styleable#View_scrollbarSize
 * @attr ref android.R.styleable#View_scrollbarStyle
 * @attr ref android.R.styleable#View_scrollbars
 * @attr ref android.R.styleable#View_scrollbarDefaultDelayBeforeFade
 * @attr ref android.R.styleable#View_scrollbarFadeDuration
 * @attr ref android.R.styleable#View_scrollbarTrackHorizontal
 * @attr ref android.R.styleable#View_scrollbarThumbHorizontal
 * @attr ref android.R.styleable#View_scrollbarThumbVertical
 * @attr ref android.R.styleable#View_scrollbarTrackVertical
 * @attr ref android.R.styleable#View_scrollbarAlwaysDrawHorizontalTrack
 * @attr ref android.R.styleable#View_scrollbarAlwaysDrawVerticalTrack
 * @attr ref android.R.styleable#View_soundEffectsEnabled
 * @attr ref android.R.styleable#View_tag
 * @attr ref android.R.styleable#View_visibility
 *
 * @see android.view.ViewGroup
 */
public class View implements Drawable.Callback, KeyEvent.Callback, AccessibilityEventSource {
    private static final boolean DBG = false;

    /**
     * The logging tag used by this class with android.util.Log.
     */
    protected static final String VIEW_LOG_TAG = "View";

    /**
     * Used to mark a View that has no ID.
     */
    public static final int NO_ID = -1;

    /**
     * This view does not want keystrokes. Use with TAKES_FOCUS_MASK when
     * calling setFlags.
     */
    private static final int NOT_FOCUSABLE = 0x00000000;

    /**
     * This view wants keystrokes. Use with TAKES_FOCUS_MASK when calling
     * setFlags.
     */
    private static final int FOCUSABLE = 0x00000001;

    /**
     * Mask for use with setFlags indicating bits used for focus.
     */
    private static final int FOCUSABLE_MASK = 0x00000001;

    /**
     * This view will adjust its padding to fit sytem windows (e.g. status bar)
     */
    private static final int FITS_SYSTEM_WINDOWS = 0x00000002;

    /**
     * This view is visible.  Use with {@link #setVisibility}.
     */
    public static final int VISIBLE = 0x00000000;

    /**
     * This view is invisible, but it still takes up space for layout purposes.
     * Use with {@link #setVisibility}.
     */
    public static final int INVISIBLE = 0x00000004;

    /**
     * This view is invisible, and it doesn't take any space for layout
     * purposes. Use with {@link #setVisibility}.
     */
    public static final int GONE = 0x00000008;

    /**
     * Mask for use with setFlags indicating bits used for visibility.
     * {@hide}
     */
    static final int VISIBILITY_MASK = 0x0000000C;

    private static final int[] VISIBILITY_FLAGS = {VISIBLE, INVISIBLE, GONE};

    /**
     * This view is enabled. Intrepretation varies by subclass.
     * Use with ENABLED_MASK when calling setFlags.
     * {@hide}
     */
    static final int ENABLED = 0x00000000;

    /**
     * This view is disabled. Intrepretation varies by subclass.
     * Use with ENABLED_MASK when calling setFlags.
     * {@hide}
     */
    static final int DISABLED = 0x00000020;

   /**
    * Mask for use with setFlags indicating bits used for indicating whether
    * this view is enabled
    * {@hide}
    */
    static final int ENABLED_MASK = 0x00000020;

    /**
     * This view won't draw. {@link #onDraw} won't be called and further
     * optimizations
     * will be performed. It is okay to have this flag set and a background.
     * Use with DRAW_MASK when calling setFlags.
     * {@hide}
     */
    static final int WILL_NOT_DRAW = 0x00000080;

    /**
     * Mask for use with setFlags indicating bits used for indicating whether
     * this view is will draw
     * {@hide}
     */
    static final int DRAW_MASK = 0x00000080;

    /**
     * <p>This view doesn't show scrollbars.</p>
     * {@hide}
     */
    static final int SCROLLBARS_NONE = 0x00000000;

    /**
     * <p>This view shows horizontal scrollbars.</p>
     * {@hide}
     */
    static final int SCROLLBARS_HORIZONTAL = 0x00000100;

    /**
     * <p>This view shows vertical scrollbars.</p>
     * {@hide}
     */
    static final int SCROLLBARS_VERTICAL = 0x00000200;

    /**
     * <p>Mask for use with setFlags indicating bits used for indicating which
     * scrollbars are enabled.</p>
     * {@hide}
     */
    static final int SCROLLBARS_MASK = 0x00000300;

    /**
     * Indicates that the view should filter touches when its window is obscured.
     * Refer to the class comments for more information about this security feature.
     * {@hide}
     */
    static final int FILTER_TOUCHES_WHEN_OBSCURED = 0x00000400;

    // note flag value 0x00000800 is now available for next flags...

    /**
     * <p>This view doesn't show fading edges.</p>
     * {@hide}
     */
    static final int FADING_EDGE_NONE = 0x00000000;

    /**
     * <p>This view shows horizontal fading edges.</p>
     * {@hide}
     */
    static final int FADING_EDGE_HORIZONTAL = 0x00001000;

    /**
     * <p>This view shows vertical fading edges.</p>
     * {@hide}
     */
    static final int FADING_EDGE_VERTICAL = 0x00002000;

    /**
     * <p>Mask for use with setFlags indicating bits used for indicating which
     * fading edges are enabled.</p>
     * {@hide}
     */
    static final int FADING_EDGE_MASK = 0x00003000;

    /**
     * <p>Indicates this view can be clicked. When clickable, a View reacts
     * to clicks by notifying the OnClickListener.<p>
     * {@hide}
     */
    static final int CLICKABLE = 0x00004000;

    /**
     * <p>Indicates this view is caching its drawing into a bitmap.</p>
     * {@hide}
     */
    static final int DRAWING_CACHE_ENABLED = 0x00008000;

    /**
     * <p>Indicates that no icicle should be saved for this view.<p>
     * {@hide}
     */
    static final int SAVE_DISABLED = 0x000010000;

    /**
     * <p>Mask for use with setFlags indicating bits used for the saveEnabled
     * property.</p>
     * {@hide}
     */
    static final int SAVE_DISABLED_MASK = 0x000010000;

    /**
     * <p>Indicates that no drawing cache should ever be created for this view.<p>
     * {@hide}
     */
    static final int WILL_NOT_CACHE_DRAWING = 0x000020000;

    /**
     * <p>Indicates this view can take / keep focus when int touch mode.</p>
     * {@hide}
     */
    static final int FOCUSABLE_IN_TOUCH_MODE = 0x00040000;

    /**
     * <p>Enables low quality mode for the drawing cache.</p>
     */
    public static final int DRAWING_CACHE_QUALITY_LOW = 0x00080000;

    /**
     * <p>Enables high quality mode for the drawing cache.</p>
     */
    public static final int DRAWING_CACHE_QUALITY_HIGH = 0x00100000;

    /**
     * <p>Enables automatic quality mode for the drawing cache.</p>
     */
    public static final int DRAWING_CACHE_QUALITY_AUTO = 0x00000000;

    private static final int[] DRAWING_CACHE_QUALITY_FLAGS = {
            DRAWING_CACHE_QUALITY_AUTO, DRAWING_CACHE_QUALITY_LOW, DRAWING_CACHE_QUALITY_HIGH
    };

    /**
     * <p>Mask for use with setFlags indicating bits used for the cache
     * quality property.</p>
     * {@hide}
     */
    static final int DRAWING_CACHE_QUALITY_MASK = 0x00180000;

    /**
     * <p>
     * Indicates this view can be long clicked. When long clickable, a View
     * reacts to long clicks by notifying the OnLongClickListener or showing a
     * context menu.
     * </p>
     * {@hide}
     */
    static final int LONG_CLICKABLE = 0x00200000;

    /**
     * <p>Indicates that this view gets its drawable states from its direct parent
     * and ignores its original internal states.</p>
     *
     * @hide
     */
    static final int DUPLICATE_PARENT_STATE = 0x00400000;

    /**
     * The scrollbar style to display the scrollbars inside the content area,
     * without increasing the padding. The scrollbars will be overlaid with
     * translucency on the view's content.
     */
    public static final int SCROLLBARS_INSIDE_OVERLAY = 0;

    /**
     * The scrollbar style to display the scrollbars inside the padded area,
     * increasing the padding of the view. The scrollbars will not overlap the
     * content area of the view.
     */
    public static final int SCROLLBARS_INSIDE_INSET = 0x01000000;

    /**
     * The scrollbar style to display the scrollbars at the edge of the view,
     * without increasing the padding. The scrollbars will be overlaid with
     * translucency.
     */
    public static final int SCROLLBARS_OUTSIDE_OVERLAY = 0x02000000;

    /**
     * The scrollbar style to display the scrollbars at the edge of the view,
     * increasing the padding of the view. The scrollbars will only overlap the
     * background, if any.
     */
    public static final int SCROLLBARS_OUTSIDE_INSET = 0x03000000;

    /**
     * Mask to check if the scrollbar style is overlay or inset.
     * {@hide}
     */
    static final int SCROLLBARS_INSET_MASK = 0x01000000;

    /**
     * Mask to check if the scrollbar style is inside or outside.
     * {@hide}
     */
    static final int SCROLLBARS_OUTSIDE_MASK = 0x02000000;

    /**
     * Mask for scrollbar style.
     * {@hide}
     */
    static final int SCROLLBARS_STYLE_MASK = 0x03000000;

    /**
     * View flag indicating that the screen should remain on while the
     * window containing this view is visible to the user.  This effectively
     * takes care of automatically setting the WindowManager's
     * {@link WindowManager.LayoutParams#FLAG_KEEP_SCREEN_ON}.
     */
    public static final int KEEP_SCREEN_ON = 0x04000000;

    /**
     * View flag indicating whether this view should have sound effects enabled
     * for events such as clicking and touching.
     */
    public static final int SOUND_EFFECTS_ENABLED = 0x08000000;

    /**
     * View flag indicating whether this view should have haptic feedback
     * enabled for events such as long presses.
     */
    public static final int HAPTIC_FEEDBACK_ENABLED = 0x10000000;

    /**
     * View flag indicating whether {@link #addFocusables(ArrayList, int, int)}
     * should add all focusable Views regardless if they are focusable in touch mode.
     */
    public static final int FOCUSABLES_ALL = 0x00000000;

    /**
     * View flag indicating whether {@link #addFocusables(ArrayList, int, int)}
     * should add only Views focusable in touch mode.
     */
    public static final int FOCUSABLES_TOUCH_MODE = 0x00000001;

    /**
     * Use with {@link #focusSearch}. Move focus to the previous selectable
     * item.
     */
    public static final int FOCUS_BACKWARD = 0x00000001;

    /**
     * Use with {@link #focusSearch}. Move focus to the next selectable
     * item.
     */
    public static final int FOCUS_FORWARD = 0x00000002;

    /**
     * Use with {@link #focusSearch}. Move focus to the left.
     */
    public static final int FOCUS_LEFT = 0x00000011;

    /**
     * Use with {@link #focusSearch}. Move focus up.
     */
    public static final int FOCUS_UP = 0x00000021;

    /**
     * Use with {@link #focusSearch}. Move focus to the right.
     */
    public static final int FOCUS_RIGHT = 0x00000042;

    /**
     * Use with {@link #focusSearch}. Move focus down.
     */
    public static final int FOCUS_DOWN = 0x00000082;

    /**
     * Base View state sets
     */
    // Singles
    /**
     * Indicates the view has no states set. States are used with
     * {@link android.graphics.drawable.Drawable} to change the drawing of the
     * view depending on its state.
     *
     * @see android.graphics.drawable.Drawable
     * @see #getDrawableState()
     */
    protected static final int[] EMPTY_STATE_SET = {};
    /**
     * Indicates the view is enabled. States are used with
     * {@link android.graphics.drawable.Drawable} to change the drawing of the
     * view depending on its state.
     *
     * @see android.graphics.drawable.Drawable
     * @see #getDrawableState()
     */
    protected static final int[] ENABLED_STATE_SET = {R.attr.state_enabled};
    /**
     * Indicates the view is focused. States are used with
     * {@link android.graphics.drawable.Drawable} to change the drawing of the
     * view depending on its state.
     *
     * @see android.graphics.drawable.Drawable
     * @see #getDrawableState()
     */
    protected static final int[] FOCUSED_STATE_SET = {R.attr.state_focused};
    /**
     * Indicates the view is selected. States are used with
     * {@link android.graphics.drawable.Drawable} to change the drawing of the
     * view depending on its state.
     *
     * @see android.graphics.drawable.Drawable
     * @see #getDrawableState()
     */
    protected static final int[] SELECTED_STATE_SET = {R.attr.state_selected};
    /**
     * Indicates the view is pressed. States are used with
     * {@link android.graphics.drawable.Drawable} to change the drawing of the
     * view depending on its state.
     *
     * @see android.graphics.drawable.Drawable
     * @see #getDrawableState()
     * @hide
     */
    protected static final int[] PRESSED_STATE_SET = {R.attr.state_pressed};
    /**
     * Indicates the view's window has focus. States are used with
     * {@link android.graphics.drawable.Drawable} to change the drawing of the
     * view depending on its state.
     *
     * @see android.graphics.drawable.Drawable
     * @see #getDrawableState()
     */
    protected static final int[] WINDOW_FOCUSED_STATE_SET =
            {R.attr.state_window_focused};
    // Doubles
    /**
     * Indicates the view is enabled and has the focus.
     *
     * @see #ENABLED_STATE_SET
     * @see #FOCUSED_STATE_SET
     */
    protected static final int[] ENABLED_FOCUSED_STATE_SET =
            stateSetUnion(ENABLED_STATE_SET, FOCUSED_STATE_SET);
    /**
     * Indicates the view is enabled and selected.
     *
     * @see #ENABLED_STATE_SET
     * @see #SELECTED_STATE_SET
     */
    protected static final int[] ENABLED_SELECTED_STATE_SET =
            stateSetUnion(ENABLED_STATE_SET, SELECTED_STATE_SET);
    /**
     * Indicates the view is enabled and that its window has focus.
     *
     * @see #ENABLED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] ENABLED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(ENABLED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
    /**
     * Indicates the view is focused and selected.
     *
     * @see #FOCUSED_STATE_SET
     * @see #SELECTED_STATE_SET
     */
    protected static final int[] FOCUSED_SELECTED_STATE_SET =
            stateSetUnion(FOCUSED_STATE_SET, SELECTED_STATE_SET);
    /**
     * Indicates the view has the focus and that its window has the focus.
     *
     * @see #FOCUSED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] FOCUSED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
    /**
     * Indicates the view is selected and that its window has the focus.
     *
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
    // Triples
    /**
     * Indicates the view is enabled, focused and selected.
     *
     * @see #ENABLED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #SELECTED_STATE_SET
     */
    protected static final int[] ENABLED_FOCUSED_SELECTED_STATE_SET =
            stateSetUnion(ENABLED_FOCUSED_STATE_SET, SELECTED_STATE_SET);
    /**
     * Indicates the view is enabled, focused and its window has the focus.
     *
     * @see #ENABLED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(ENABLED_FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
    /**
     * Indicates the view is enabled, selected and its window has the focus.
     *
     * @see #ENABLED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(ENABLED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
    /**
     * Indicates the view is focused, selected and its window has the focus.
     *
     * @see #FOCUSED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(FOCUSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);
    /**
     * Indicates the view is enabled, focused, selected and its window
     * has the focus.
     *
     * @see #ENABLED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(ENABLED_FOCUSED_SELECTED_STATE_SET,
                          WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed and its window has the focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed and selected.
     *
     * @see #PRESSED_STATE_SET
     * @see #SELECTED_STATE_SET
     */
    protected static final int[] PRESSED_SELECTED_STATE_SET =
            stateSetUnion(PRESSED_STATE_SET, SELECTED_STATE_SET);

    /**
     * Indicates the view is pressed, selected and its window has the focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed and focused.
     *
     * @see #PRESSED_STATE_SET
     * @see #FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_STATE_SET, FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed, focused and its window has the focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed, focused and selected.
     *
     * @see #PRESSED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_FOCUSED_SELECTED_STATE_SET =
            stateSetUnion(PRESSED_FOCUSED_STATE_SET, SELECTED_STATE_SET);

    /**
     * Indicates the view is pressed, focused, selected and its window has the focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_FOCUSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed and enabled.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_STATE_SET =
            stateSetUnion(PRESSED_STATE_SET, ENABLED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled and its window has the focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled and selected.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #SELECTED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_SELECTED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_STATE_SET, SELECTED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled, selected and its window has the
     * focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled and focused.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_STATE_SET, FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled, focused and its window has the
     * focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_FOCUSED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled, focused and selected.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_FOCUSED_STATE_SET, SELECTED_STATE_SET);

    /**
     * Indicates the view is pressed, enabled, focused, selected and its window
     * has the focus.
     *
     * @see #PRESSED_STATE_SET
     * @see #ENABLED_STATE_SET
     * @see #SELECTED_STATE_SET
     * @see #FOCUSED_STATE_SET
     * @see #WINDOW_FOCUSED_STATE_SET
     */
    protected static final int[] PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET =
            stateSetUnion(PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET, WINDOW_FOCUSED_STATE_SET);

    /**
     * The order here is very important to {@link #getDrawableState()}
     */
    private static final int[][] VIEW_STATE_SETS = {
        EMPTY_STATE_SET,                                           // 0 0 0 0 0
        WINDOW_FOCUSED_STATE_SET,                                  // 0 0 0 0 1
        SELECTED_STATE_SET,                                        // 0 0 0 1 0
        SELECTED_WINDOW_FOCUSED_STATE_SET,                         // 0 0 0 1 1
        FOCUSED_STATE_SET,                                         // 0 0 1 0 0
        FOCUSED_WINDOW_FOCUSED_STATE_SET,                          // 0 0 1 0 1
        FOCUSED_SELECTED_STATE_SET,                                // 0 0 1 1 0
        FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET,                 // 0 0 1 1 1
        ENABLED_STATE_SET,                                         // 0 1 0 0 0
        ENABLED_WINDOW_FOCUSED_STATE_SET,                          // 0 1 0 0 1
        ENABLED_SELECTED_STATE_SET,                                // 0 1 0 1 0
        ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET,                 // 0 1 0 1 1
        ENABLED_FOCUSED_STATE_SET,                                 // 0 1 1 0 0
        ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET,                  // 0 1 1 0 1
        ENABLED_FOCUSED_SELECTED_STATE_SET,                        // 0 1 1 1 0
        ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET,         // 0 1 1 1 1
        PRESSED_STATE_SET,                                         // 1 0 0 0 0
        PRESSED_WINDOW_FOCUSED_STATE_SET,                          // 1 0 0 0 1
        PRESSED_SELECTED_STATE_SET,                                // 1 0 0 1 0
        PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET,                 // 1 0 0 1 1
        PRESSED_FOCUSED_STATE_SET,                                 // 1 0 1 0 0
        PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET,                  // 1 0 1 0 1
        PRESSED_FOCUSED_SELECTED_STATE_SET,                        // 1 0 1 1 0
        PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET,         // 1 0 1 1 1
        PRESSED_ENABLED_STATE_SET,                                 // 1 1 0 0 0
        PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET,                  // 1 1 0 0 1
        PRESSED_ENABLED_SELECTED_STATE_SET,                        // 1 1 0 1 0
        PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET,         // 1 1 0 1 1
        PRESSED_ENABLED_FOCUSED_STATE_SET,                         // 1 1 1 0 0
        PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET,          // 1 1 1 0 1
        PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET,                // 1 1 1 1 0
        PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, // 1 1 1 1 1
    };

    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is showing the last item.
     * @hide
     */
    protected static final int[] LAST_STATE_SET = {R.attr.state_last};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is showing the first item.
     * @hide
     */
    protected static final int[] FIRST_STATE_SET = {R.attr.state_first};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is showing the middle item.
     * @hide
     */
    protected static final int[] MIDDLE_STATE_SET = {R.attr.state_middle};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is showing only one item.
     * @hide
     */
    protected static final int[] SINGLE_STATE_SET = {R.attr.state_single};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is pressed and showing the last item.
     * @hide
     */
    protected static final int[] PRESSED_LAST_STATE_SET = {R.attr.state_last, R.attr.state_pressed};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is pressed and showing the first item.
     * @hide
     */
    protected static final int[] PRESSED_FIRST_STATE_SET = {R.attr.state_first, R.attr.state_pressed};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is pressed and showing the middle item.
     * @hide
     */
    protected static final int[] PRESSED_MIDDLE_STATE_SET = {R.attr.state_middle, R.attr.state_pressed};
    /**
     * Used by views that contain lists of items. This state indicates that
     * the view is pressed and showing only one item.
     * @hide
     */
    protected static final int[] PRESSED_SINGLE_STATE_SET = {R.attr.state_single, R.attr.state_pressed};

    /**
     * Temporary Rect currently for use in setBackground().  This will probably
     * be extended in the future to hold our own class with more than just
     * a Rect. :)
     */
    static final ThreadLocal<Rect> sThreadLocal = new ThreadLocal<Rect>();

    /**
     * Map used to store views' tags.
     */
    private static WeakHashMap<View, SparseArray<Object>> sTags;

    /**
     * Lock used to access sTags.
     */
    private static final Object sTagsLock = new Object();

    /**
     * The animation currently associated with this view.
     * @hide
     */
    protected Animation mCurrentAnimation = null;

    /**
     * Width as measured during measure pass.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "measurement")
    protected int mMeasuredWidth;

    /**
     * Height as measured during measure pass.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "measurement")
    protected int mMeasuredHeight;

    /**
     * The view's identifier.
     * {@hide}
     *
     * @see #setId(int)
     * @see #getId()
     */
    @ViewDebug.ExportedProperty(resolveId = true)
    int mID = NO_ID;

    /**
     * The view's tag.
     * {@hide}
     *
     * @see #setTag(Object)
     * @see #getTag()
     */
    protected Object mTag;

    // for mPrivateFlags:
    /** {@hide} */
    static final int WANTS_FOCUS                    = 0x00000001;
    /** {@hide} */
    static final int FOCUSED                        = 0x00000002;
    /** {@hide} */
    static final int SELECTED                       = 0x00000004;
    /** {@hide} */
    static final int IS_ROOT_NAMESPACE              = 0x00000008;
    /** {@hide} */
    static final int HAS_BOUNDS                     = 0x00000010;
    /** {@hide} */
    static final int DRAWN                          = 0x00000020;
    /**
     * When this flag is set, this view is running an animation on behalf of its
     * children and should therefore not cancel invalidate requests, even if they
     * lie outside of this view's bounds.
     *
     * {@hide}
     */
    static final int DRAW_ANIMATION                 = 0x00000040;
    /** {@hide} */
    static final int SKIP_DRAW                      = 0x00000080;
    /** {@hide} */
    static final int ONLY_DRAWS_BACKGROUND          = 0x00000100;
    /** {@hide} */
    static final int REQUEST_TRANSPARENT_REGIONS    = 0x00000200;
    /** {@hide} */
    static final int DRAWABLE_STATE_DIRTY           = 0x00000400;
    /** {@hide} */
    static final int MEASURED_DIMENSION_SET         = 0x00000800;
    /** {@hide} */
    static final int FORCE_LAYOUT                   = 0x00001000;
    /** {@hide} */
    static final int LAYOUT_REQUIRED                = 0x00002000;

    private static final int PRESSED                = 0x00004000;

    /** {@hide} */
    static final int DRAWING_CACHE_VALID            = 0x00008000;
    /**
     * Flag used to indicate that this view should be drawn once more (and only once
     * more) after its animation has completed.
     * {@hide}
     */
    static final int ANIMATION_STARTED              = 0x00010000;

    private static final int SAVE_STATE_CALLED      = 0x00020000;

    /**
     * Indicates that the View returned true when onSetAlpha() was called and that
     * the alpha must be restored.
     * {@hide}
     */
    static final int ALPHA_SET                      = 0x00040000;

    /**
     * Set by {@link #setScrollContainer(boolean)}.
     */
    static final int SCROLL_CONTAINER               = 0x00080000;

    /**
     * Set by {@link #setScrollContainer(boolean)}.
     */
    static final int SCROLL_CONTAINER_ADDED         = 0x00100000;

    /**
     * View flag indicating whether this view was invalidated (fully or partially.)
     *
     * @hide
     */
    static final int DIRTY                          = 0x00200000;

    /**
     * View flag indicating whether this view was invalidated by an opaque
     * invalidate request.
     *
     * @hide
     */
    static final int DIRTY_OPAQUE                   = 0x00400000;

    /**
     * Mask for {@link #DIRTY} and {@link #DIRTY_OPAQUE}.
     *
     * @hide
     */
    static final int DIRTY_MASK                     = 0x00600000;

    /**
     * Indicates whether the background is opaque.
     *
     * @hide
     */
    static final int OPAQUE_BACKGROUND              = 0x00800000;

    /**
     * Indicates whether the scrollbars are opaque.
     *
     * @hide
     */
    static final int OPAQUE_SCROLLBARS              = 0x01000000;

    /**
     * Indicates whether the view is opaque.
     *
     * @hide
     */
    static final int OPAQUE_MASK                    = 0x01800000;

    /**
     * Indicates a prepressed state;
     * the short time between ACTION_DOWN and recognizing
     * a 'real' press. Prepressed is used to recognize quick taps
     * even when they are shorter than ViewConfiguration.getTapTimeout().
     *
     * @hide
     */
    private static final int PREPRESSED             = 0x02000000;

    /**
     * Indicates whether the view is temporarily detached.
     *
     * @hide
     */
    static final int CANCEL_NEXT_UP_EVENT = 0x04000000;

    /**
     * Indicates that we should awaken scroll bars once attached
     *
     * @hide
     */
    private static final int AWAKEN_SCROLL_BARS_ON_ATTACH = 0x08000000;

    /**
     * Always allow a user to over-scroll this view, provided it is a
     * view that can scroll.
     *
     * @see #getOverScrollMode()
     * @see #setOverScrollMode(int)
     */
    public static final int OVER_SCROLL_ALWAYS = 0;

    /**
     * Allow a user to over-scroll this view only if the content is large
     * enough to meaningfully scroll, provided it is a view that can scroll.
     *
     * @see #getOverScrollMode()
     * @see #setOverScrollMode(int)
     */
    public static final int OVER_SCROLL_IF_CONTENT_SCROLLS = 1;

    /**
     * Never allow a user to over-scroll this view.
     *
     * @see #getOverScrollMode()
     * @see #setOverScrollMode(int)
     */
    public static final int OVER_SCROLL_NEVER = 2;

    /**
     * Controls the over-scroll mode for this view.
     * See {@link #overScrollBy(int, int, int, int, int, int, int, int, boolean)},
     * {@link #OVER_SCROLL_ALWAYS}, {@link #OVER_SCROLL_IF_CONTENT_SCROLLS},
     * and {@link #OVER_SCROLL_NEVER}.
     */
    private int mOverScrollMode;

    /**
     * The parent this view is attached to.
     * {@hide}
     *
     * @see #getParent()
     */
    protected ViewParent mParent;

    /**
     * {@hide}
     */
    AttachInfo mAttachInfo;

    /**
     * {@hide}
     */
    @ViewDebug.ExportedProperty(flagMapping = {
        @ViewDebug.FlagToString(mask = FORCE_LAYOUT, equals = FORCE_LAYOUT,
                name = "FORCE_LAYOUT"),
        @ViewDebug.FlagToString(mask = LAYOUT_REQUIRED, equals = LAYOUT_REQUIRED,
                name = "LAYOUT_REQUIRED"),
        @ViewDebug.FlagToString(mask = DRAWING_CACHE_VALID, equals = DRAWING_CACHE_VALID,
            name = "DRAWING_CACHE_INVALID", outputIf = false),
        @ViewDebug.FlagToString(mask = DRAWN, equals = DRAWN, name = "DRAWN", outputIf = true),
        @ViewDebug.FlagToString(mask = DRAWN, equals = DRAWN, name = "NOT_DRAWN", outputIf = false),
        @ViewDebug.FlagToString(mask = DIRTY_MASK, equals = DIRTY_OPAQUE, name = "DIRTY_OPAQUE"),
        @ViewDebug.FlagToString(mask = DIRTY_MASK, equals = DIRTY, name = "DIRTY")
    })
    int mPrivateFlags;

    /**
     * Count of how many windows this view has been attached to.
     */
    int mWindowAttachCount;

    /**
     * The layout parameters associated with this view and used by the parent
     * {@link android.view.ViewGroup} to determine how this view should be
     * laid out.
     * {@hide}
     */
    protected ViewGroup.LayoutParams mLayoutParams;

    /**
     * The view flags hold various views states.
     * {@hide}
     */
    @ViewDebug.ExportedProperty
    int mViewFlags;

    /**
     * The distance in pixels from the left edge of this view's parent
     * to the left edge of this view.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "layout")
    protected int mLeft;
    /**
     * The distance in pixels from the left edge of this view's parent
     * to the right edge of this view.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "layout")
    protected int mRight;
    /**
     * The distance in pixels from the top edge of this view's parent
     * to the top edge of this view.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "layout")
    protected int mTop;
    /**
     * The distance in pixels from the top edge of this view's parent
     * to the bottom edge of this view.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "layout")
    protected int mBottom;

    /**
     * The offset, in pixels, by which the content of this view is scrolled
     * horizontally.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "scrolling")
    protected int mScrollX;
    /**
     * The offset, in pixels, by which the content of this view is scrolled
     * vertically.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "scrolling")
    protected int mScrollY;

    /**
     * The left padding in pixels, that is the distance in pixels between the
     * left edge of this view and the left edge of its content.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "padding")
    protected int mPaddingLeft;
    /**
     * The right padding in pixels, that is the distance in pixels between the
     * right edge of this view and the right edge of its content.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "padding")
    protected int mPaddingRight;
    /**
     * The top padding in pixels, that is the distance in pixels between the
     * top edge of this view and the top edge of its content.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "padding")
    protected int mPaddingTop;
    /**
     * The bottom padding in pixels, that is the distance in pixels between the
     * bottom edge of this view and the bottom edge of its content.
     * {@hide}
     */
    @ViewDebug.ExportedProperty(category = "padding")
    protected int mPaddingBottom;

    /**
     * Briefly describes the view and is primarily used for accessibility support.
     */
    private CharSequence mContentDescription;

    /**
     * Cache the paddingRight set by the user to append to the scrollbar's size.
     */
    @ViewDebug.ExportedProperty(category = "padding")
    int mUserPaddingRight;

    /**
     * Cache the paddingBottom set by the user to append to the scrollbar's size.
     */
    @ViewDebug.ExportedProperty(category = "padding")
    int mUserPaddingBottom;

    /**
     * @hide
     */
    int mOldWidthMeasureSpec = Integer.MIN_VALUE;
    /**
     * @hide
     */
    int mOldHeightMeasureSpec = Integer.MIN_VALUE;

    private Resources mResources = null;

    private Drawable mBGDrawable;

    private int mBackgroundResource;
    private boolean mBackgroundSizeChanged;

    /**
     * Listener used to dispatch focus change events.
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected OnFocusChangeListener mOnFocusChangeListener;

    /**
     * Listener used to dispatch click events.
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected OnClickListener mOnClickListener;

    /**
     * Listener used to dispatch long click events.
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected OnLongClickListener mOnLongClickListener;

    /**
     * Listener used to build the context menu.
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected OnCreateContextMenuListener mOnCreateContextMenuListener;

    private OnKeyListener mOnKeyListener;

    private OnTouchListener mOnTouchListener;

    /**
     * The application environment this view lives in.
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected Context mContext;

    private ScrollabilityCache mScrollCache;

    private int[] mDrawableState = null;

    private SoftReference<Bitmap> mDrawingCache;
    private SoftReference<Bitmap> mUnscaledDrawingCache;

    /**
     * When this view has focus and the next focus is {@link #FOCUS_LEFT},
     * the user may specify which view to go to next.
     */
    private int mNextFocusLeftId = View.NO_ID;

    /**
     * When this view has focus and the next focus is {@link #FOCUS_RIGHT},
     * the user may specify which view to go to next.
     */
    private int mNextFocusRightId = View.NO_ID;

    /**
     * When this view has focus and the next focus is {@link #FOCUS_UP},
     * the user may specify which view to go to next.
     */
    private int mNextFocusUpId = View.NO_ID;

    /**
     * When this view has focus and the next focus is {@link #FOCUS_DOWN},
     * the user may specify which view to go to next.
     */
    private int mNextFocusDownId = View.NO_ID;

    private CheckForLongPress mPendingCheckForLongPress;
    private CheckForTap mPendingCheckForTap = null;
    private PerformClick mPerformClick;

    private UnsetPressedState mUnsetPressedState;

    /**
     * Whether the long press's action has been invoked.  The tap's action is invoked on the
     * up event while a long press is invoked as soon as the long press duration is reached, so
     * a long press could be performed before the tap is checked, in which case the tap's action
     * should not be invoked.
     */
    private boolean mHasPerformedLongPress;

    /**
     * The minimum height of the view. We'll try our best to have the height
     * of this view to at least this amount.
     */
    @ViewDebug.ExportedProperty(category = "measurement")
    private int mMinHeight;

    /**
     * The minimum width of the view. We'll try our best to have the width
     * of this view to at least this amount.
     */
    @ViewDebug.ExportedProperty(category = "measurement")
    private int mMinWidth;

    /**
     * The delegate to handle touch events that are physically in this view
     * but should be handled by another view.
     */
    private TouchDelegate mTouchDelegate = null;

    /**
     * Solid color to use as a background when creating the drawing cache. Enables
     * the cache to use 16 bit bitmaps instead of 32 bit.
     */
    private int mDrawingCacheBackgroundColor = 0;

    /**
     * Special tree observer used when mAttachInfo is null.
     */
    private ViewTreeObserver mFloatingTreeObserver;

    /**
     * Cache the touch slop from the context that created the view.
     */
    private int mTouchSlop;

    // Used for debug only
    static long sInstanceCount = 0;

    /**
     * Simple constructor to use when creating a view from code.
     *
     * @param context The Context the view is running in, through which it can
     *        access the current theme, resources, etc.
     */
    public View(Context context) {
        mContext = context;
        mResources = context != null ? context.getResources() : null;
        mViewFlags = SOUND_EFFECTS_ENABLED | HAPTIC_FEEDBACK_ENABLED;
        // Used for debug only
        //++sInstanceCount;
        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
        setOverScrollMode(OVER_SCROLL_IF_CONTENT_SCROLLS);
    }

    /**
     * Constructor that is called when inflating a view from XML. This is called
     * when a view is being constructed from an XML file, supplying attributes
     * that were specified in the XML file. This version uses a default style of
     * 0, so the only attribute values applied are those in the Context's Theme
     * and the given AttributeSet.
     *
     * <p>
     * The method onFinishInflate() will be called after all children have been
     * added.
     *
     * @param context The Context the view is running in, through which it can
     *        access the current theme, resources, etc.
     * @param attrs The attributes of the XML tag that is inflating the view.
     * @see #View(Context, AttributeSet, int)
     */
    public View(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    /**
     * Perform inflation from XML and apply a class-specific base style. This
     * constructor of View allows subclasses to use their own base style when
     * they are inflating. For example, a Button class's constructor would call
     * this version of the super class constructor and supply
     * <code>R.attr.buttonStyle</code> for <var>defStyle</var>; this allows
     * the theme's button style to modify all of the base view attributes (in
     * particular its background) as well as the Button class's attributes.
     *
     * @param context The Context the view is running in, through which it can
     *        access the current theme, resources, etc.
     * @param attrs The attributes of the XML tag that is inflating the view.
     * @param defStyle The default style to apply to this view. If 0, no style
     *        will be applied (beyond what is included in the theme). This may
     *        either be an attribute resource, whose value will be retrieved
     *        from the current theme, or an explicit style resource.
     * @see #View(Context, AttributeSet)
     */
    public View(Context context, AttributeSet attrs, int defStyle) {
        this(context);

        TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.View,
                defStyle, 0);

        Drawable background = null;

        int leftPadding = -1;
        int topPadding = -1;
        int rightPadding = -1;
        int bottomPadding = -1;

        int padding = -1;

        int viewFlagValues = 0;
        int viewFlagMasks = 0;

        boolean setScrollContainer = false;

        int x = 0;
        int y = 0;

        int scrollbarStyle = SCROLLBARS_INSIDE_OVERLAY;

        int overScrollMode = mOverScrollMode;
        final int N = a.getIndexCount();
        for (int i = 0; i < N; i++) {
            int attr = a.getIndex(i);
            switch (attr) {
                case com.android.internal.R.styleable.View_background:
                    background = a.getDrawable(attr);
                    break;
                case com.android.internal.R.styleable.View_padding:
                    padding = a.getDimensionPixelSize(attr, -1);
                    break;
                 case com.android.internal.R.styleable.View_paddingLeft:
                    leftPadding = a.getDimensionPixelSize(attr, -1);
                    break;
                case com.android.internal.R.styleable.View_paddingTop:
                    topPadding = a.getDimensionPixelSize(attr, -1);
                    break;
                case com.android.internal.R.styleable.View_paddingRight:
                    rightPadding = a.getDimensionPixelSize(attr, -1);
                    break;
                case com.android.internal.R.styleable.View_paddingBottom:
                    bottomPadding = a.getDimensionPixelSize(attr, -1);
                    break;
                case com.android.internal.R.styleable.View_scrollX:
                    x = a.getDimensionPixelOffset(attr, 0);
                    break;
                case com.android.internal.R.styleable.View_scrollY:
                    y = a.getDimensionPixelOffset(attr, 0);
                    break;
                case com.android.internal.R.styleable.View_id:
                    mID = a.getResourceId(attr, NO_ID);
                    break;
                case com.android.internal.R.styleable.View_tag:
                    mTag = a.getText(attr);
                    break;
                case com.android.internal.R.styleable.View_fitsSystemWindows:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= FITS_SYSTEM_WINDOWS;
                        viewFlagMasks |= FITS_SYSTEM_WINDOWS;
                    }
                    break;
                case com.android.internal.R.styleable.View_focusable:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= FOCUSABLE;
                        viewFlagMasks |= FOCUSABLE_MASK;
                    }
                    break;
                case com.android.internal.R.styleable.View_focusableInTouchMode:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= FOCUSABLE_IN_TOUCH_MODE | FOCUSABLE;
                        viewFlagMasks |= FOCUSABLE_IN_TOUCH_MODE | FOCUSABLE_MASK;
                    }
                    break;
                case com.android.internal.R.styleable.View_clickable:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= CLICKABLE;
                        viewFlagMasks |= CLICKABLE;
                    }
                    break;
                case com.android.internal.R.styleable.View_longClickable:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= LONG_CLICKABLE;
                        viewFlagMasks |= LONG_CLICKABLE;
                    }
                    break;
                case com.android.internal.R.styleable.View_saveEnabled:
                    if (!a.getBoolean(attr, true)) {
                        viewFlagValues |= SAVE_DISABLED;
                        viewFlagMasks |= SAVE_DISABLED_MASK;
                    }
                    break;
                case com.android.internal.R.styleable.View_duplicateParentState:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= DUPLICATE_PARENT_STATE;
                        viewFlagMasks |= DUPLICATE_PARENT_STATE;
                    }
                    break;
                case com.android.internal.R.styleable.View_visibility:
                    final int visibility = a.getInt(attr, 0);
                    if (visibility != 0) {
                        viewFlagValues |= VISIBILITY_FLAGS[visibility];
                        viewFlagMasks |= VISIBILITY_MASK;
                    }
                    break;
                case com.android.internal.R.styleable.View_drawingCacheQuality:
                    final int cacheQuality = a.getInt(attr, 0);
                    if (cacheQuality != 0) {
                        viewFlagValues |= DRAWING_CACHE_QUALITY_FLAGS[cacheQuality];
                        viewFlagMasks |= DRAWING_CACHE_QUALITY_MASK;
                    }
                    break;
                case com.android.internal.R.styleable.View_contentDescription:
                    mContentDescription = a.getString(attr);
                    break;
                case com.android.internal.R.styleable.View_soundEffectsEnabled:
                    if (!a.getBoolean(attr, true)) {
                        viewFlagValues &= ~SOUND_EFFECTS_ENABLED;
                        viewFlagMasks |= SOUND_EFFECTS_ENABLED;
                    }
                    break;
                case com.android.internal.R.styleable.View_hapticFeedbackEnabled:
                    if (!a.getBoolean(attr, true)) {
                        viewFlagValues &= ~HAPTIC_FEEDBACK_ENABLED;
                        viewFlagMasks |= HAPTIC_FEEDBACK_ENABLED;
                    }
                    break;
                case R.styleable.View_scrollbars:
                    final int scrollbars = a.getInt(attr, SCROLLBARS_NONE);
                    if (scrollbars != SCROLLBARS_NONE) {
                        viewFlagValues |= scrollbars;
                        viewFlagMasks |= SCROLLBARS_MASK;
                        initializeScrollbars(a);
                    }
                    break;
                case R.styleable.View_fadingEdge:
                    final int fadingEdge = a.getInt(attr, FADING_EDGE_NONE);
                    if (fadingEdge != FADING_EDGE_NONE) {
                        viewFlagValues |= fadingEdge;
                        viewFlagMasks |= FADING_EDGE_MASK;
                        initializeFadingEdge(a);
                    }
                    break;
                case R.styleable.View_scrollbarStyle:
                    scrollbarStyle = a.getInt(attr, SCROLLBARS_INSIDE_OVERLAY);
                    if (scrollbarStyle != SCROLLBARS_INSIDE_OVERLAY) {
                        viewFlagValues |= scrollbarStyle & SCROLLBARS_STYLE_MASK;
                        viewFlagMasks |= SCROLLBARS_STYLE_MASK;
                    }
                    break;
                case R.styleable.View_isScrollContainer:
                    setScrollContainer = true;
                    if (a.getBoolean(attr, false)) {
                        setScrollContainer(true);
                    }
                    break;
                case com.android.internal.R.styleable.View_keepScreenOn:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= KEEP_SCREEN_ON;
                        viewFlagMasks |= KEEP_SCREEN_ON;
                    }
                    break;
                case R.styleable.View_filterTouchesWhenObscured:
                    if (a.getBoolean(attr, false)) {
                        viewFlagValues |= FILTER_TOUCHES_WHEN_OBSCURED;
                        viewFlagMasks |= FILTER_TOUCHES_WHEN_OBSCURED;
                    }
                    break;
                case R.styleable.View_nextFocusLeft:
                    mNextFocusLeftId = a.getResourceId(attr, View.NO_ID);
                    break;
                case R.styleable.View_nextFocusRight:
                    mNextFocusRightId = a.getResourceId(attr, View.NO_ID);
                    break;
                case R.styleable.View_nextFocusUp:
                    mNextFocusUpId = a.getResourceId(attr, View.NO_ID);
                    break;
                case R.styleable.View_nextFocusDown:
                    mNextFocusDownId = a.getResourceId(attr, View.NO_ID);
                    break;
                case R.styleable.View_minWidth:
                    mMinWidth = a.getDimensionPixelSize(attr, 0);
                    break;
                case R.styleable.View_minHeight:
                    mMinHeight = a.getDimensionPixelSize(attr, 0);
                    break;
                case R.styleable.View_onClick:
                    if (context.isRestricted()) {
                        throw new IllegalStateException("The android:onClick attribute cannot "
                                + "be used within a restricted context");
                    }

                    final String handlerName = a.getString(attr);
                    if (handlerName != null) {
                        setOnClickListener(new OnClickListener() {
                            private Method mHandler;

                            public void onClick(View v) {
                                if (mHandler == null) {
                                    try {
                                        mHandler = getContext().getClass().getMethod(handlerName,
                                                View.class);
                                    } catch (NoSuchMethodException e) {
                                        int id = getId();
                                        String idText = id == NO_ID ? "" : " with id '"
                                                + getContext().getResources().getResourceEntryName(
                                                    id) + "'";
                                        throw new IllegalStateException("Could not find a method " +
                                                handlerName + "(View) in the activity "
                                                + getContext().getClass() + " for onClick handler"
                                                + " on view " + View.this.getClass() + idText, e);
                                    }
                                }

                                try {
                                    mHandler.invoke(getContext(), View.this);
                                } catch (IllegalAccessException e) {
                                    throw new IllegalStateException("Could not execute non "
                                            + "public method of the activity", e);
                                } catch (InvocationTargetException e) {
                                    throw new IllegalStateException("Could not execute "
                                            + "method of the activity", e);
                                }
                            }
                        });
                    }
                    break;
                case R.styleable.View_overScrollMode:
                    overScrollMode = a.getInt(attr, OVER_SCROLL_IF_CONTENT_SCROLLS);
                    break;
            }
        }

        setOverScrollMode(overScrollMode);

        if (background != null) {
            setBackgroundDrawable(background);
        }

        if (padding >= 0) {
            leftPadding = padding;
            topPadding = padding;
            rightPadding = padding;
            bottomPadding = padding;
        }

        // If the user specified the padding (either with android:padding or
        // android:paddingLeft/Top/Right/Bottom), use this padding, otherwise
        // use the default padding or the padding from the background drawable
        // (stored at this point in mPadding*)
        setPadding(leftPadding >= 0 ? leftPadding : mPaddingLeft,
                topPadding >= 0 ? topPadding : mPaddingTop,
                rightPadding >= 0 ? rightPadding : mPaddingRight,
                bottomPadding >= 0 ? bottomPadding : mPaddingBottom);

        if (viewFlagMasks != 0) {
            setFlags(viewFlagValues, viewFlagMasks);
        }

        // Needs to be called after mViewFlags is set
        if (scrollbarStyle != SCROLLBARS_INSIDE_OVERLAY) {
            recomputePadding();
        }

        if (x != 0 || y != 0) {
            scrollTo(x, y);
        }

        if (!setScrollContainer && (viewFlagValues&SCROLLBARS_VERTICAL) != 0) {
            setScrollContainer(true);
        }

        computeOpaqueFlags();

        a.recycle();
    }

    /**
     * Non-public constructor for use in testing
     */
    View() {
    }

    // Used for debug only
    /*
    @Override
    protected void finalize() throws Throwable {
        super.finalize();
        --sInstanceCount;
    }
    */

    /**
     * <p>
     * Initializes the fading edges from a given set of styled attributes. This
     * method should be called by subclasses that need fading edges and when an
     * instance of these subclasses is created programmatically rather than
     * being inflated from XML. This method is automatically called when the XML
     * is inflated.
     * </p>
     *
     * @param a the styled attributes set to initialize the fading edges from
     */
    protected void initializeFadingEdge(TypedArray a) {
        initScrollCache();

        mScrollCache.fadingEdgeLength = a.getDimensionPixelSize(
                R.styleable.View_fadingEdgeLength,
                ViewConfiguration.get(mContext).getScaledFadingEdgeLength());
    }

    /**
     * Returns the size of the vertical faded edges used to indicate that more
     * content in this view is visible.
     *
     * @return The size in pixels of the vertical faded edge or 0 if vertical
     *         faded edges are not enabled for this view.
     * @attr ref android.R.styleable#View_fadingEdgeLength
     */
    public int getVerticalFadingEdgeLength() {
        if (isVerticalFadingEdgeEnabled()) {
            ScrollabilityCache cache = mScrollCache;
            if (cache != null) {
                return cache.fadingEdgeLength;
            }
        }
        return 0;
    }

    /**
     * Set the size of the faded edge used to indicate that more content in this
     * view is available.  Will not change whether the fading edge is enabled; use
     * {@link #setVerticalFadingEdgeEnabled} or {@link #setHorizontalFadingEdgeEnabled}
     * to enable the fading edge for the vertical or horizontal fading edges.
     *
     * @param length The size in pixels of the faded edge used to indicate that more
     *        content in this view is visible.
     */
    public void setFadingEdgeLength(int length) {
        initScrollCache();
        mScrollCache.fadingEdgeLength = length;
    }

    /**
     * Returns the size of the horizontal faded edges used to indicate that more
     * content in this view is visible.
     *
     * @return The size in pixels of the horizontal faded edge or 0 if horizontal
     *         faded edges are not enabled for this view.
     * @attr ref android.R.styleable#View_fadingEdgeLength
     */
    public int getHorizontalFadingEdgeLength() {
        if (isHorizontalFadingEdgeEnabled()) {
            ScrollabilityCache cache = mScrollCache;
            if (cache != null) {
                return cache.fadingEdgeLength;
            }
        }
        return 0;
    }

    /**
     * Returns the width of the vertical scrollbar.
     *
     * @return The width in pixels of the vertical scrollbar or 0 if there
     *         is no vertical scrollbar.
     */
    public int getVerticalScrollbarWidth() {
        ScrollabilityCache cache = mScrollCache;
        if (cache != null) {
            ScrollBarDrawable scrollBar = cache.scrollBar;
            if (scrollBar != null) {
                int size = scrollBar.getSize(true);
                if (size <= 0) {
                    size = cache.scrollBarSize;
                }
                return size;
            }
            return 0;
        }
        return 0;
    }

    /**
     * Returns the height of the horizontal scrollbar.
     *
     * @return The height in pixels of the horizontal scrollbar or 0 if
     *         there is no horizontal scrollbar.
     */
    protected int getHorizontalScrollbarHeight() {
        ScrollabilityCache cache = mScrollCache;
        if (cache != null) {
            ScrollBarDrawable scrollBar = cache.scrollBar;
            if (scrollBar != null) {
                int size = scrollBar.getSize(false);
                if (size <= 0) {
                    size = cache.scrollBarSize;
                }
                return size;
            }
            return 0;
        }
        return 0;
    }

    /**
     * <p>
     * Initializes the scrollbars from a given set of styled attributes. This
     * method should be called by subclasses that need scrollbars and when an
     * instance of these subclasses is created programmatically rather than
     * being inflated from XML. This method is automatically called when the XML
     * is inflated.
     * </p>
     *
     * @param a the styled attributes set to initialize the scrollbars from
     */
    protected void initializeScrollbars(TypedArray a) {
        initScrollCache();

        final ScrollabilityCache scrollabilityCache = mScrollCache;

        if (scrollabilityCache.scrollBar == null) {
            scrollabilityCache.scrollBar = new ScrollBarDrawable();
        }

        final boolean fadeScrollbars = a.getBoolean(R.styleable.View_fadeScrollbars, true);

        if (!fadeScrollbars) {
            scrollabilityCache.state = ScrollabilityCache.ON;
        }
        scrollabilityCache.fadeScrollBars = fadeScrollbars;


        scrollabilityCache.scrollBarFadeDuration = a.getInt(
                R.styleable.View_scrollbarFadeDuration, ViewConfiguration
                        .getScrollBarFadeDuration());
        scrollabilityCache.scrollBarDefaultDelayBeforeFade = a.getInt(
                R.styleable.View_scrollbarDefaultDelayBeforeFade,
                ViewConfiguration.getScrollDefaultDelay());


        scrollabilityCache.scrollBarSize = a.getDimensionPixelSize(
                com.android.internal.R.styleable.View_scrollbarSize,
                ViewConfiguration.get(mContext).getScaledScrollBarSize());

        Drawable track = a.getDrawable(R.styleable.View_scrollbarTrackHorizontal);
        scrollabilityCache.scrollBar.setHorizontalTrackDrawable(track);

        Drawable thumb = a.getDrawable(R.styleable.View_scrollbarThumbHorizontal);
        if (thumb != null) {
            scrollabilityCache.scrollBar.setHorizontalThumbDrawable(thumb);
        }

        boolean alwaysDraw = a.getBoolean(R.styleable.View_scrollbarAlwaysDrawHorizontalTrack,
                false);
        if (alwaysDraw) {
            scrollabilityCache.scrollBar.setAlwaysDrawHorizontalTrack(true);
        }

        track = a.getDrawable(R.styleable.View_scrollbarTrackVertical);
        scrollabilityCache.scrollBar.setVerticalTrackDrawable(track);

        thumb = a.getDrawable(R.styleable.View_scrollbarThumbVertical);
        if (thumb != null) {
            scrollabilityCache.scrollBar.setVerticalThumbDrawable(thumb);
        }

        alwaysDraw = a.getBoolean(R.styleable.View_scrollbarAlwaysDrawVerticalTrack,
                false);
        if (alwaysDraw) {
            scrollabilityCache.scrollBar.setAlwaysDrawVerticalTrack(true);
        }

        // Re-apply user/background padding so that scrollbar(s) get added
        recomputePadding();
    }

    /**
     * <p>
     * Initalizes the scrollability cache if necessary.
     * </p>
     */
    private void initScrollCache() {
        if (mScrollCache == null) {
            mScrollCache = new ScrollabilityCache(ViewConfiguration.get(mContext), this);
        }
    }

    /**
     * Register a callback to be invoked when focus of this view changed.
     *
     * @param l The callback that will run.
     */
    public void setOnFocusChangeListener(OnFocusChangeListener l) {
        mOnFocusChangeListener = l;
    }

    /**
     * Returns the focus-change callback registered for this view.
     *
     * @return The callback, or null if one is not registered.
     */
    public OnFocusChangeListener getOnFocusChangeListener() {
        return mOnFocusChangeListener;
    }

    /**
     * Register a callback to be invoked when this view is clicked. If this view is not
     * clickable, it becomes clickable.
     *
     * @param l The callback that will run
     *
     * @see #setClickable(boolean)
     */
    public void setOnClickListener(OnClickListener l) {
        if (!isClickable()) {
            setClickable(true);
        }
        mOnClickListener = l;
    }

    /**
     * Register a callback to be invoked when this view is clicked and held. If this view is not
     * long clickable, it becomes long clickable.
     *
     * @param l The callback that will run
     *
     * @see #setLongClickable(boolean)
     */
    public void setOnLongClickListener(OnLongClickListener l) {
        if (!isLongClickable()) {
            setLongClickable(true);
        }
        mOnLongClickListener = l;
    }

    /**
     * Register a callback to be invoked when the context menu for this view is
     * being built. If this view is not long clickable, it becomes long clickable.
     *
     * @param l The callback that will run
     *
     */
    public void setOnCreateContextMenuListener(OnCreateContextMenuListener l) {
        if (!isLongClickable()) {
            setLongClickable(true);
        }
        mOnCreateContextMenuListener = l;
    }

    /**
     * Call this view's OnClickListener, if it is defined.
     *
     * @return True there was an assigned OnClickListener that was called, false
     *         otherwise is returned.
     */
    public boolean performClick() {
        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);

        if (mOnClickListener != null) {
            playSoundEffect(SoundEffectConstants.CLICK);
            mOnClickListener.onClick(this);
            return true;
        }

        return false;
    }

    /**
     * Call this view's OnLongClickListener, if it is defined. Invokes the context menu if the
     * OnLongClickListener did not consume the event.
     *
     * @return True if one of the above receivers consumed the event, false otherwise.
     */
    public boolean performLongClick() {
        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_LONG_CLICKED);

        boolean handled = false;
        if (mOnLongClickListener != null) {
            handled = mOnLongClickListener.onLongClick(View.this);
        }
        if (!handled) {
            handled = showContextMenu();
        }
        if (handled) {
            performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
        }
        return handled;
    }

    /**
     * Bring up the context menu for this view.
     *
     * @return Whether a context menu was displayed.
     */
    public boolean showContextMenu() {
        return getParent().showContextMenuForChild(this);
    }

    /**
     * Register a callback to be invoked when a key is pressed in this view.
     * @param l the key listener to attach to this view
     */
    public void setOnKeyListener(OnKeyListener l) {
        mOnKeyListener = l;
    }

    /**
     * Register a callback to be invoked when a touch event is sent to this view.
     * @param l the touch listener to attach to this view
     */
    public void setOnTouchListener(OnTouchListener l) {
        mOnTouchListener = l;
    }

    /**
     * Give this view focus. This will cause {@link #onFocusChanged} to be called.
     *
     * Note: this does not check whether this {@link View} should get focus, it just
     * gives it focus no matter what.  It should only be called internally by framework
     * code that knows what it is doing, namely {@link #requestFocus(int, Rect)}.
     *
     * @param direction values are View.FOCUS_UP, View.FOCUS_DOWN,
     *        View.FOCUS_LEFT or View.FOCUS_RIGHT. This is the direction which
     *        focus moved when requestFocus() is called. It may not always
     *        apply, in which case use the default View.FOCUS_DOWN.
     * @param previouslyFocusedRect The rectangle of the view that had focus
     *        prior in this View's coordinate system.
     */
    void handleFocusGainInternal(int direction, Rect previouslyFocusedRect) {
        if (DBG) {
            System.out.println(this + " requestFocus()");
        }

        if ((mPrivateFlags & FOCUSED) == 0) {
            mPrivateFlags |= FOCUSED;

            if (mParent != null) {
                mParent.requestChildFocus(this, this);
            }

            onFocusChanged(true, direction, previouslyFocusedRect);
            refreshDrawableState();
        }
    }

    /**
     * Request that a rectangle of this view be visible on the screen,
     * scrolling if necessary just enough.
     *
     * <p>A View should call this if it maintains some notion of which part
     * of its content is interesting.  For example, a text editing view
     * should call this when its cursor moves.
     *
     * @param rectangle The rectangle.
     * @return Whether any parent scrolled.
     */
    public boolean requestRectangleOnScreen(Rect rectangle) {
        return requestRectangleOnScreen(rectangle, false);
    }

    /**
     * Request that a rectangle of this view be visible on the screen,
     * scrolling if necessary just enough.
     *
     * <p>A View should call this if it maintains some notion of which part
     * of its content is interesting.  For example, a text editing view
     * should call this when its cursor moves.
     *
     * <p>When <code>immediate</code> is set to true, scrolling will not be
     * animated.
     *
     * @param rectangle The rectangle.
     * @param immediate True to forbid animated scrolling, false otherwise
     * @return Whether any parent scrolled.
     */
    public boolean requestRectangleOnScreen(Rect rectangle, boolean immediate) {
        View child = this;
        ViewParent parent = mParent;
        boolean scrolled = false;
        while (parent != null) {
            scrolled |= parent.requestChildRectangleOnScreen(child,
                    rectangle, immediate);

            // offset rect so next call has the rectangle in the
            // coordinate system of its direct child.
            rectangle.offset(child.getLeft(), child.getTop());
            rectangle.offset(-child.getScrollX(), -child.getScrollY());

            if (!(parent instanceof View)) {
                break;
            }

            child = (View) parent;
            parent = child.getParent();
        }
        return scrolled;
    }

    /**
     * Called when this view wants to give up focus. This will cause
     * {@link #onFocusChanged} to be called.
     */
    public void clearFocus() {
        if (DBG) {
            System.out.println(this + " clearFocus()");
        }

        if ((mPrivateFlags & FOCUSED) != 0) {
            mPrivateFlags &= ~FOCUSED;

            if (mParent != null) {
                mParent.clearChildFocus(this);
            }

            onFocusChanged(false, 0, null);
            refreshDrawableState();
        }
    }

    /**
     * Called to clear the focus of a view that is about to be removed.
     * Doesn't call clearChildFocus, which prevents this view from taking
     * focus again before it has been removed from the parent
     */
    void clearFocusForRemoval() {
        if ((mPrivateFlags & FOCUSED) != 0) {
            mPrivateFlags &= ~FOCUSED;

            onFocusChanged(false, 0, null);
            refreshDrawableState();
        }
    }

    /**
     * Called internally by the view system when a new view is getting focus.
     * This is what clears the old focus.
     */
    void unFocus() {
        if (DBG) {
            System.out.println(this + " unFocus()");
        }

        if ((mPrivateFlags & FOCUSED) != 0) {
            mPrivateFlags &= ~FOCUSED;

            onFocusChanged(false, 0, null);
            refreshDrawableState();
        }
    }

    /**
     * Returns true if this view has focus iteself, or is the ancestor of the
     * view that has focus.
     *
     * @return True if this view has or contains focus, false otherwise.
     */
    @ViewDebug.ExportedProperty(category = "focus")
    public boolean hasFocus() {
        return (mPrivateFlags & FOCUSED) != 0;
    }

    /**
     * Returns true if this view is focusable or if it contains a reachable View
     * for which {@link #hasFocusable()} returns true. A "reachable hasFocusable()"
     * is a View whose parents do not block descendants focus.
     *
     * Only {@link #VISIBLE} views are considered focusable.
     *
     * @return True if the view is focusable or if the view contains a focusable
     *         View, false otherwise.
     *
     * @see ViewGroup#FOCUS_BLOCK_DESCENDANTS
     */
    public boolean hasFocusable() {
        return (mViewFlags & VISIBILITY_MASK) == VISIBLE && isFocusable();
    }

    /**
     * Called by the view system when the focus state of this view changes.
     * When the focus change event is caused by directional navigation, direction
     * and previouslyFocusedRect provide insight into where the focus is coming from.
     * When overriding, be sure to call up through to the super class so that
     * the standard focus handling will occur.
     *
     * @param gainFocus True if the View has focus; false otherwise.
     * @param direction The direction focus has moved when requestFocus()
     *                  is called to give this view focus. Values are
     *                  {@link #FOCUS_UP}, {@link #FOCUS_DOWN}, {@link #FOCUS_LEFT} or
     *                  {@link #FOCUS_RIGHT}. It may not always apply, in which
     *                  case use the default.
     * @param previouslyFocusedRect The rectangle, in this view's coordinate
     *        system, of the previously focused view.  If applicable, this will be
     *        passed in as finer grained information about where the focus is coming
     *        from (in addition to direction).  Will be <code>null</code> otherwise.
     */
    protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
        if (gainFocus) {
            sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
        }

        InputMethodManager imm = InputMethodManager.peekInstance();
        if (!gainFocus) {
            if (isPressed()) {
                setPressed(false);
            }
            if (imm != null && mAttachInfo != null
                    && mAttachInfo.mHasWindowFocus) {
                imm.focusOut(this);
            }
            onFocusLost();
        } else if (imm != null && mAttachInfo != null
                && mAttachInfo.mHasWindowFocus) {
            imm.focusIn(this);
        }

        invalidate();
        if (mOnFocusChangeListener != null) {
            mOnFocusChangeListener.onFocusChange(this, gainFocus);
        }

        if (mAttachInfo != null) {
            mAttachInfo.mKeyDispatchState.reset(this);
        }
    }

    /**
     * {@inheritDoc}
     */
    public void sendAccessibilityEvent(int eventType) {
        if (AccessibilityManager.getInstance(mContext).isEnabled()) {
            sendAccessibilityEventUnchecked(AccessibilityEvent.obtain(eventType));
        }
    }

    /**
     * {@inheritDoc}
     */
    public void sendAccessibilityEventUnchecked(AccessibilityEvent event) {
        event.setClassName(getClass().getName());
        event.setPackageName(getContext().getPackageName());
        event.setEnabled(isEnabled());
        event.setContentDescription(mContentDescription);

        if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_FOCUSED && mAttachInfo != null) {
            ArrayList<View> focusablesTempList = mAttachInfo.mFocusablesTempList;
            getRootView().addFocusables(focusablesTempList, View.FOCUS_FORWARD, FOCUSABLES_ALL);
            event.setItemCount(focusablesTempList.size());
            event.setCurrentItemIndex(focusablesTempList.indexOf(this));
            focusablesTempList.clear();
        }

        dispatchPopulateAccessibilityEvent(event);

        AccessibilityManager.getInstance(mContext).sendAccessibilityEvent(event);
    }

    /**
     * Dispatches an {@link AccessibilityEvent} to the {@link View} children
     * to be populated.
     *
     * @param event The event.
     *
     * @return True if the event population was completed.
     */
    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
        return false;
    }

    /**
     * Gets the {@link View} description. It briefly describes the view and is
     * primarily used for accessibility support. Set this property to enable
     * better accessibility support for your application. This is especially
     * true for views that do not have textual representation (For example,
     * ImageButton).
     *
     * @return The content descriptiopn.
     *
     * @attr ref android.R.styleable#View_contentDescription
     */
    public CharSequence getContentDescription() {
        return mContentDescription;
    }

    /**
     * Sets the {@link View} description. It briefly describes the view and is
     * primarily used for accessibility support. Set this property to enable
     * better accessibility support for your application. This is especially
     * true for views that do not have textual representation (For example,
     * ImageButton).
     *
     * @param contentDescription The content description.
     *
     * @attr ref android.R.styleable#View_contentDescription
     */
    public void setContentDescription(CharSequence contentDescription) {
        mContentDescription = contentDescription;
    }

    /**
     * Invoked whenever this view loses focus, either by losing window focus or by losing
     * focus within its window. This method can be used to clear any state tied to the
     * focus. For instance, if a button is held pressed with the trackball and the window
     * loses focus, this method can be used to cancel the press.
     *
     * Subclasses of View overriding this method should always call super.onFocusLost().
     *
     * @see #onFocusChanged(boolean, int, android.graphics.Rect)
     * @see #onWindowFocusChanged(boolean)
     *
     * @hide pending API council approval
     */
    protected void onFocusLost() {
        resetPressedState();
    }

    private void resetPressedState() {
        if ((mViewFlags & ENABLED_MASK) == DISABLED) {
            return;
        }

        if (isPressed()) {
            setPressed(false);

            if (!mHasPerformedLongPress) {
                removeLongPressCallback();
            }
        }
    }

    /**
     * Returns true if this view has focus
     *
     * @return True if this view has focus, false otherwise.
     */
    @ViewDebug.ExportedProperty(category = "focus")
    public boolean isFocused() {
        return (mPrivateFlags & FOCUSED) != 0;
    }

    /**
     * Find the view in the hierarchy rooted at this view that currently has
     * focus.
     *
     * @return The view that currently has focus, or null if no focused view can
     *         be found.
     */
    public View findFocus() {
        return (mPrivateFlags & FOCUSED) != 0 ? this : null;
    }

    /**
     * Change whether this view is one of the set of scrollable containers in
     * its window.  This will be used to determine whether the window can
     * resize or must pan when a soft input area is open -- scrollable
     * containers allow the window to use resize mode since the container
     * will appropriately shrink.
     */
    public void setScrollContainer(boolean isScrollContainer) {
        if (isScrollContainer) {
            if (mAttachInfo != null && (mPrivateFlags&SCROLL_CONTAINER_ADDED) == 0) {
                mAttachInfo.mScrollContainers.add(this);
                mPrivateFlags |= SCROLL_CONTAINER_ADDED;
            }
            mPrivateFlags |= SCROLL_CONTAINER;
        } else {
            if ((mPrivateFlags&SCROLL_CONTAINER_ADDED) != 0) {
                mAttachInfo.mScrollContainers.remove(this);
            }
            mPrivateFlags &= ~(SCROLL_CONTAINER|SCROLL_CONTAINER_ADDED);
        }
    }

    /**
     * Returns the quality of the drawing cache.
     *
     * @return One of {@link #DRAWING_CACHE_QUALITY_AUTO},
     *         {@link #DRAWING_CACHE_QUALITY_LOW}, or {@link #DRAWING_CACHE_QUALITY_HIGH}
     *
     * @see #setDrawingCacheQuality(int)
     * @see #setDrawingCacheEnabled(boolean)
     * @see #isDrawingCacheEnabled()
     *
     * @attr ref android.R.styleable#View_drawingCacheQuality
     */
    public int getDrawingCacheQuality() {
        return mViewFlags & DRAWING_CACHE_QUALITY_MASK;
    }

    /**
     * Set the drawing cache quality of this view. This value is used only when the
     * drawing cache is enabled
     *
     * @param quality One of {@link #DRAWING_CACHE_QUALITY_AUTO},
     *        {@link #DRAWING_CACHE_QUALITY_LOW}, or {@link #DRAWING_CACHE_QUALITY_HIGH}
     *
     * @see #getDrawingCacheQuality()
     * @see #setDrawingCacheEnabled(boolean)
     * @see #isDrawingCacheEnabled()
     *
     * @attr ref android.R.styleable#View_drawingCacheQuality
     */
    public void setDrawingCacheQuality(int quality) {
        setFlags(quality, DRAWING_CACHE_QUALITY_MASK);
    }

    /**
     * Returns whether the screen should remain on, corresponding to the current
     * value of {@link #KEEP_SCREEN_ON}.
     *
     * @return Returns true if {@link #KEEP_SCREEN_ON} is set.
     *
     * @see #setKeepScreenOn(boolean)
     *
     * @attr ref android.R.styleable#View_keepScreenOn
     */
    public boolean getKeepScreenOn() {
        return (mViewFlags & KEEP_SCREEN_ON) != 0;
    }

    /**
     * Controls whether the screen should remain on, modifying the
     * value of {@link #KEEP_SCREEN_ON}.
     *
     * @param keepScreenOn Supply true to set {@link #KEEP_SCREEN_ON}.
     *
     * @see #getKeepScreenOn()
     *
     * @attr ref android.R.styleable#View_keepScreenOn
     */
    public void setKeepScreenOn(boolean keepScreenOn) {
        setFlags(keepScreenOn ? KEEP_SCREEN_ON : 0, KEEP_SCREEN_ON);
    }

    /**
     * @return The user specified next focus ID.
     *
     * @attr ref android.R.styleable#View_nextFocusLeft
     */
    public int getNextFocusLeftId() {
        return mNextFocusLeftId;
    }

    /**
     * Set the id of the view to use for the next focus
     *
     * @param nextFocusLeftId
     *
     * @attr ref android.R.styleable#View_nextFocusLeft
     */
    public void setNextFocusLeftId(int nextFocusLeftId) {
        mNextFocusLeftId = nextFocusLeftId;
    }

    /**
     * @return The user specified next focus ID.
     *
     * @attr ref android.R.styleable#View_nextFocusRight
     */
    public int getNextFocusRightId() {
        return mNextFocusRightId;
    }

    /**
     * Set the id of the view to use for the next focus
     *
     * @param nextFocusRightId
     *
     * @attr ref android.R.styleable#View_nextFocusRight
     */
    public void setNextFocusRightId(int nextFocusRightId) {
        mNextFocusRightId = nextFocusRightId;
    }

    /**
     * @return The user specified next focus ID.
     *
     * @attr ref android.R.styleable#View_nextFocusUp
     */
    public int getNextFocusUpId() {
        return mNextFocusUpId;
    }

    /**
     * Set the id of the view to use for the next focus
     *
     * @param nextFocusUpId
     *
     * @attr ref android.R.styleable#View_nextFocusUp
     */
    public void setNextFocusUpId(int nextFocusUpId) {
        mNextFocusUpId = nextFocusUpId;
    }

    /**
     * @return The user specified next focus ID.
     *
     * @attr ref android.R.styleable#View_nextFocusDown
     */
    public int getNextFocusDownId() {
        return mNextFocusDownId;
    }

    /**
     * Set the id of the view to use for the next focus
     *
     * @param nextFocusDownId
     *
     * @attr ref android.R.styleable#View_nextFocusDown
     */
    public void setNextFocusDownId(int nextFocusDownId) {
        mNextFocusDownId = nextFocusDownId;
    }

    /**
     * Returns the visibility of this view and all of its ancestors
     *
     * @return True if this view and all of its ancestors are {@link #VISIBLE}
     */
    public boolean isShown() {
        View current = this;
        //noinspection ConstantConditions
        do {
            if ((current.mViewFlags & VISIBILITY_MASK) != VISIBLE) {
                return false;
            }
            ViewParent parent = current.mParent;
            if (parent == null) {
                return false; // We are not attached to the view root
            }
            if (!(parent instanceof View)) {
                return true;
            }
            current = (View) parent;
        } while (current != null);

        return false;
    }

    /**
     * Apply the insets for system windows to this view, if the FITS_SYSTEM_WINDOWS flag
     * is set
     *
     * @param insets Insets for system windows
     *
     * @return True if this view applied the insets, false otherwise
     */
    protected boolean fitSystemWindows(Rect insets) {
        if ((mViewFlags & FITS_SYSTEM_WINDOWS) == FITS_SYSTEM_WINDOWS) {
            mPaddingLeft = insets.left;
            mPaddingTop = insets.top;
            mPaddingRight = insets.right;
            mPaddingBottom = insets.bottom;
            requestLayout();
            return true;
        }
        return false;
    }

    /**
     * Determine if this view has the FITS_SYSTEM_WINDOWS flag set.
     * @return True if window has FITS_SYSTEM_WINDOWS set
     *
     * @hide
     */
    public boolean isFitsSystemWindowsFlagSet() {
        return (mViewFlags & FITS_SYSTEM_WINDOWS) == FITS_SYSTEM_WINDOWS;
    }

    /**
     * Returns the visibility status for this view.
     *
     * @return One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
     * @attr ref android.R.styleable#View_visibility
     */
    @ViewDebug.ExportedProperty(mapping = {
        @ViewDebug.IntToString(from = VISIBLE,   to = "VISIBLE"),
        @ViewDebug.IntToString(from = INVISIBLE, to = "INVISIBLE"),
        @ViewDebug.IntToString(from = GONE,      to = "GONE")
    })
    public int getVisibility() {
        return mViewFlags & VISIBILITY_MASK;
    }

    /**
     * Set the enabled state of this view.
     *
     * @param visibility One of {@link #VISIBLE}, {@link #INVISIBLE}, or {@link #GONE}.
     * @attr ref android.R.styleable#View_visibility
     */
    @RemotableViewMethod
    public void setVisibility(int visibility) {
        setFlags(visibility, VISIBILITY_MASK);
        if (mBGDrawable != null) mBGDrawable.setVisible(visibility == VISIBLE, false);
    }

    /**
     * Returns the enabled status for this view. The interpretation of the
     * enabled state varies by subclass.
     *
     * @return True if this view is enabled, false otherwise.
     */
    @ViewDebug.ExportedProperty
    public boolean isEnabled() {
        return (mViewFlags & ENABLED_MASK) == ENABLED;
    }

    /**
     * Set the enabled state of this view. The interpretation of the enabled
     * state varies by subclass.
     *
     * @param enabled True if this view is enabled, false otherwise.
     */
    @RemotableViewMethod
    public void setEnabled(boolean enabled) {
        if (enabled == isEnabled()) return;

        setFlags(enabled ? ENABLED : DISABLED, ENABLED_MASK);

        /*
         * The View most likely has to change its appearance, so refresh
         * the drawable state.
         */
        refreshDrawableState();

        // Invalidate too, since the default behavior for views is to be
        // be drawn at 50% alpha rather than to change the drawable.
        invalidate();
    }

    /**
     * Set whether this view can receive the focus.
     *
     * Setting this to false will also ensure that this view is not focusable
     * in touch mode.
     *
     * @param focusable If true, this view can receive the focus.
     *
     * @see #setFocusableInTouchMode(boolean)
     * @attr ref android.R.styleable#View_focusable
     */
    public void setFocusable(boolean focusable) {
        if (!focusable) {
            setFlags(0, FOCUSABLE_IN_TOUCH_MODE);
        }
        setFlags(focusable ? FOCUSABLE : NOT_FOCUSABLE, FOCUSABLE_MASK);
    }

    /**
     * Set whether this view can receive focus while in touch mode.
     *
     * Setting this to true will also ensure that this view is focusable.
     *
     * @param focusableInTouchMode If true, this view can receive the focus while
     *   in touch mode.
     *
     * @see #setFocusable(boolean)
     * @attr ref android.R.styleable#View_focusableInTouchMode
     */
    public void setFocusableInTouchMode(boolean focusableInTouchMode) {
        // Focusable in touch mode should always be set before the focusable flag
        // otherwise, setting the focusable flag will trigger a focusableViewAvailable()
        // which, in touch mode, will not successfully request focus on this view
        // because the focusable in touch mode flag is not set
        setFlags(focusableInTouchMode ? FOCUSABLE_IN_TOUCH_MODE : 0, FOCUSABLE_IN_TOUCH_MODE);
        if (focusableInTouchMode) {
            setFlags(FOCUSABLE, FOCUSABLE_MASK);
        }
    }

    /**
     * Set whether this view should have sound effects enabled for events such as
     * clicking and touching.
     *
     * <p>You may wish to disable sound effects for a view if you already play sounds,
     * for instance, a dial key that plays dtmf tones.
     *
     * @param soundEffectsEnabled whether sound effects are enabled for this view.
     * @see #isSoundEffectsEnabled()
     * @see #playSoundEffect(int)
     * @attr ref android.R.styleable#View_soundEffectsEnabled
     */
    public void setSoundEffectsEnabled(boolean soundEffectsEnabled) {
        setFlags(soundEffectsEnabled ? SOUND_EFFECTS_ENABLED: 0, SOUND_EFFECTS_ENABLED);
    }

    /**
     * @return whether this view should have sound effects enabled for events such as
     *     clicking and touching.
     *
     * @see #setSoundEffectsEnabled(boolean)
     * @see #playSoundEffect(int)
     * @attr ref android.R.styleable#View_soundEffectsEnabled
     */
    @ViewDebug.ExportedProperty
    public boolean isSoundEffectsEnabled() {
        return SOUND_EFFECTS_ENABLED == (mViewFlags & SOUND_EFFECTS_ENABLED);
    }

    /**
     * Set whether this view should have haptic feedback for events such as
     * long presses.
     *
     * <p>You may wish to disable haptic feedback if your view already controls
     * its own haptic feedback.
     *
     * @param hapticFeedbackEnabled whether haptic feedback enabled for this view.
     * @see #isHapticFeedbackEnabled()
     * @see #performHapticFeedback(int)
     * @attr ref android.R.styleable#View_hapticFeedbackEnabled
     */
    public void setHapticFeedbackEnabled(boolean hapticFeedbackEnabled) {
        setFlags(hapticFeedbackEnabled ? HAPTIC_FEEDBACK_ENABLED: 0, HAPTIC_FEEDBACK_ENABLED);
    }

    /**
     * @return whether this view should have haptic feedback enabled for events
     * long presses.
     *
     * @see #setHapticFeedbackEnabled(boolean)
     * @see #performHapticFeedback(int)
     * @attr ref android.R.styleable#View_hapticFeedbackEnabled
     */
    @ViewDebug.ExportedProperty
    public boolean isHapticFeedbackEnabled() {
        return HAPTIC_FEEDBACK_ENABLED == (mViewFlags & HAPTIC_FEEDBACK_ENABLED);
    }

    /**
     * If this view doesn't do any drawing on its own, set this flag to
     * allow further optimizations. By default, this flag is not set on
     * View, but could be set on some View subclasses such as ViewGroup.
     *
     * Typically, if you override {@link #onDraw} you should clear this flag.
     *
     * @param willNotDraw whether or not this View draw on its own
     */
    public void setWillNotDraw(boolean willNotDraw) {
        setFlags(willNotDraw ? WILL_NOT_DRAW : 0, DRAW_MASK);
    }

    /**
     * Returns whether or not this View draws on its own.
     *
     * @return true if this view has nothing to draw, false otherwise
     */
    @ViewDebug.ExportedProperty(category = "drawing")
    public boolean willNotDraw() {
        return (mViewFlags & DRAW_MASK) == WILL_NOT_DRAW;
    }

    /**
     * When a View's drawing cache is enabled, drawing is redirected to an
     * offscreen bitmap. Some views, like an ImageView, must be able to
     * bypass this mechanism if they already draw a single bitmap, to avoid
     * unnecessary usage of the memory.
     *
     * @param willNotCacheDrawing true if this view does not cache its
     *        drawing, false otherwise
     */
    public void setWillNotCacheDrawing(boolean willNotCacheDrawing) {
        setFlags(willNotCacheDrawing ? WILL_NOT_CACHE_DRAWING : 0, WILL_NOT_CACHE_DRAWING);
    }

    /**
     * Returns whether or not this View can cache its drawing or not.
     *
     * @return true if this view does not cache its drawing, false otherwise
     */
    @ViewDebug.ExportedProperty(category = "drawing")
    public boolean willNotCacheDrawing() {
        return (mViewFlags & WILL_NOT_CACHE_DRAWING) == WILL_NOT_CACHE_DRAWING;
    }

    /**
     * Indicates whether this view reacts to click events or not.
     *
     * @return true if the view is clickable, false otherwise
     *
     * @see #setClickable(boolean)
     * @attr ref android.R.styleable#View_clickable
     */
    @ViewDebug.ExportedProperty
    public boolean isClickable() {
        return (mViewFlags & CLICKABLE) == CLICKABLE;
    }

    /**
     * Enables or disables click events for this view. When a view
     * is clickable it will change its state to "pressed" on every click.
     * Subclasses should set the view clickable to visually react to
     * user's clicks.
     *
     * @param clickable true to make the view clickable, false otherwise
     *
     * @see #isClickable()
     * @attr ref android.R.styleable#View_clickable
     */
    public void setClickable(boolean clickable) {
        setFlags(clickable ? CLICKABLE : 0, CLICKABLE);
    }

    /**
     * Indicates whether this view reacts to long click events or not.
     *
     * @return true if the view is long clickable, false otherwise
     *
     * @see #setLongClickable(boolean)
     * @attr ref android.R.styleable#View_longClickable
     */
    public boolean isLongClickable() {
        return (mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE;
    }

    /**
     * Enables or disables long click events for this view. When a view is long
     * clickable it reacts to the user holding down the button for a longer
     * duration than a tap. This event can either launch the listener or a
     * context menu.
     *
     * @param longClickable true to make the view long clickable, false otherwise
     * @see #isLongClickable()
     * @attr ref android.R.styleable#View_longClickable
     */
    public void setLongClickable(boolean longClickable) {
        setFlags(longClickable ? LONG_CLICKABLE : 0, LONG_CLICKABLE);
    }

    /**
     * Sets the pressed that for this view.
     *
     * @see #isClickable()
     * @see #setClickable(boolean)
     *
     * @param pressed Pass true to set the View's internal state to "pressed", or false to reverts
     *        the View's internal state from a previously set "pressed" state.
     */
    public void setPressed(boolean pressed) {
        if (pressed) {
            mPrivateFlags |= PRESSED;
        } else {
            mPrivateFlags &= ~PRESSED;
        }
        refreshDrawableState();
        dispatchSetPressed(pressed);
    }

    /**
     * Dispatch setPressed to all of this View's children.
     *
     * @see #setPressed(boolean)
     *
     * @param pressed The new pressed state
     */
    protected void dispatchSetPressed(boolean pressed) {
    }

    /**
     * Indicates whether the view is currently in pressed state. Unless
     * {@link #setPressed(boolean)} is explicitly called, only clickable views can enter
     * the pressed state.
     *
     * @see #setPressed
     * @see #isClickable()
     * @see #setClickable(boolean)
     *
     * @return true if the view is currently pressed, false otherwise
     */
    public boolean isPressed() {
        return (mPrivateFlags & PRESSED) == PRESSED;
    }

    /**
     * Indicates whether this view will save its state (that is,
     * whether its {@link #onSaveInstanceState} method will be called).
     *
     * @return Returns true if the view state saving is enabled, else false.
     *
     * @see #setSaveEnabled(boolean)
     * @attr ref android.R.styleable#View_saveEnabled
     */
    public boolean isSaveEnabled() {
        return (mViewFlags & SAVE_DISABLED_MASK) != SAVE_DISABLED;
    }

    /**
     * Controls whether the saving of this view's state is
     * enabled (that is, whether its {@link #onSaveInstanceState} method
     * will be called).  Note that even if freezing is enabled, the
     * view still must have an id assigned to it (via {@link #setId setId()})
     * for its state to be saved.  This flag can only disable the
     * saving of this view; any child views may still have their state saved.
     *
     * @param enabled Set to false to <em>disable</em> state saving, or true
     * (the default) to allow it.
     *
     * @see #isSaveEnabled()
     * @see #setId(int)
     * @see #onSaveInstanceState()
     * @attr ref android.R.styleable#View_saveEnabled
     */
    public void setSaveEnabled(boolean enabled) {
        setFlags(enabled ? 0 : SAVE_DISABLED, SAVE_DISABLED_MASK);
    }

    /**
     * Gets whether the framework should discard touches when the view's
     * window is obscured by another visible window.
     * Refer to the {@link View} security documentation for more details.
     *
     * @return True if touch filtering is enabled.
     *
     * @see #setFilterTouchesWhenObscured(boolean)
     * @attr ref android.R.styleable#View_filterTouchesWhenObscured
     */
    @ViewDebug.ExportedProperty
    public boolean getFilterTouchesWhenObscured() {
        return (mViewFlags & FILTER_TOUCHES_WHEN_OBSCURED) != 0;
    }

    /**
     * Sets whether the framework should discard touches when the view's
     * window is obscured by another visible window.
     * Refer to the {@link View} security documentation for more details.
     *
     * @param enabled True if touch filtering should be enabled.
     *
     * @see #getFilterTouchesWhenObscured
     * @attr ref android.R.styleable#View_filterTouchesWhenObscured
     */
    public void setFilterTouchesWhenObscured(boolean enabled) {
        setFlags(enabled ? 0 : FILTER_TOUCHES_WHEN_OBSCURED,
                FILTER_TOUCHES_WHEN_OBSCURED);
    }

    /**
     * Returns whether this View is able to take focus.
     *
     * @return True if this view can take focus, or false otherwise.
     * @attr ref android.R.styleable#View_focusable
     */
    @ViewDebug.ExportedProperty(category = "focus")
    public final boolean isFocusable() {
        return FOCUSABLE == (mViewFlags & FOCUSABLE_MASK);
    }

    /**
     * When a view is focusable, it may not want to take focus when in touch mode.
     * For example, a button would like focus when the user is navigating via a D-pad
     * so that the user can click on it, but once the user starts touching the screen,
     * the button shouldn't take focus
     * @return Whether the view is focusable in touch mode.
     * @attr ref android.R.styleable#View_focusableInTouchMode
     */
    @ViewDebug.ExportedProperty
    public final boolean isFocusableInTouchMode() {
        return FOCUSABLE_IN_TOUCH_MODE == (mViewFlags & FOCUSABLE_IN_TOUCH_MODE);
    }

    /**
     * Find the nearest view in the specified direction that can take focus.
     * This does not actually give focus to that view.
     *
     * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
     *
     * @return The nearest focusable in the specified direction, or null if none
     *         can be found.
     */
    public View focusSearch(int direction) {
        if (mParent != null) {
            return mParent.focusSearch(this, direction);
        } else {
            return null;
        }
    }

    /**
     * This method is the last chance for the focused view and its ancestors to
     * respond to an arrow key. This is called when the focused view did not
     * consume the key internally, nor could the view system find a new view in
     * the requested direction to give focus to.
     *
     * @param focused The currently focused view.
     * @param direction The direction focus wants to move. One of FOCUS_UP,
     *        FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT.
     * @return True if the this view consumed this unhandled move.
     */
    public boolean dispatchUnhandledMove(View focused, int direction) {
        return false;
    }

    /**
     * If a user manually specified the next view id for a particular direction,
     * use the root to look up the view.  Once a view is found, it is cached
     * for future lookups.
     * @param root The root view of the hierarchy containing this view.
     * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
     * @return The user specified next view, or null if there is none.
     */
    View findUserSetNextFocus(View root, int direction) {
        switch (direction) {
            case FOCUS_LEFT:
                if (mNextFocusLeftId == View.NO_ID) return null;
                return findViewShouldExist(root, mNextFocusLeftId);
            case FOCUS_RIGHT:
                if (mNextFocusRightId == View.NO_ID) return null;
                return findViewShouldExist(root, mNextFocusRightId);
            case FOCUS_UP:
                if (mNextFocusUpId == View.NO_ID) return null;
                return findViewShouldExist(root, mNextFocusUpId);
            case FOCUS_DOWN:
                if (mNextFocusDownId == View.NO_ID) return null;
                return findViewShouldExist(root, mNextFocusDownId);
        }
        return null;
    }

    private static View findViewShouldExist(View root, int childViewId) {
        View result = root.findViewById(childViewId);
        if (result == null) {
            Log.w(VIEW_LOG_TAG, "couldn't find next focus view specified "
                    + "by user for id " + childViewId);
        }
        return result;
    }

    /**
     * Find and return all focusable views that are descendants of this view,
     * possibly including this view if it is focusable itself.
     *
     * @param direction The direction of the focus
     * @return A list of focusable views
     */
    public ArrayList<View> getFocusables(int direction) {
        ArrayList<View> result = new ArrayList<View>(24);
        addFocusables(result, direction);
        return result;
    }

    /**
     * Add any focusable views that are descendants of this view (possibly
     * including this view if it is focusable itself) to views.  If we are in touch mode,
     * only add views that are also focusable in touch mode.
     *
     * @param views Focusable views found so far
     * @param direction The direction of the focus
     */
    public void addFocusables(ArrayList<View> views, int direction) {
        addFocusables(views, direction, FOCUSABLES_TOUCH_MODE);
    }

    /**
     * Adds any focusable views that are descendants of this view (possibly
     * including this view if it is focusable itself) to views. This method
     * adds all focusable views regardless if we are in touch mode or
     * only views focusable in touch mode if we are in touch mode depending on
     * the focusable mode paramater.
     *
     * @param views Focusable views found so far or null if all we are interested is
     *        the number of focusables.
     * @param direction The direction of the focus.
     * @param focusableMode The type of focusables to be added.
     *
     * @see #FOCUSABLES_ALL
     * @see #FOCUSABLES_TOUCH_MODE
     */
    public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
        if (!isFocusable()) {
            return;
        }

        if ((focusableMode & FOCUSABLES_TOUCH_MODE) == FOCUSABLES_TOUCH_MODE &&
                isInTouchMode() && !isFocusableInTouchMode()) {
            return;
        }

        if (views != null) {
            views.add(this);
        }
    }

    /**
     * Find and return all touchable views that are descendants of this view,
     * possibly including this view if it is touchable itself.
     *
     * @return A list of touchable views
     */
    public ArrayList<View> getTouchables() {
        ArrayList<View> result = new ArrayList<View>();
        addTouchables(result);
        return result;
    }

    /**
     * Add any touchable views that are descendants of this view (possibly
     * including this view if it is touchable itself) to views.
     *
     * @param views Touchable views found so far
     */
    public void addTouchables(ArrayList<View> views) {
        final int viewFlags = mViewFlags;

        if (((viewFlags & CLICKABLE) == CLICKABLE || (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)
                && (viewFlags & ENABLED_MASK) == ENABLED) {
            views.add(this);
        }
    }

    /**
     * Call this to try to give focus to a specific view or to one of its
     * descendants.
     *
     * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns false),
     * or if it is focusable and it is not focusable in touch mode ({@link #isFocusableInTouchMode})
     * while the device is in touch mode.
     *
     * See also {@link #focusSearch}, which is what you call to say that you
     * have focus, and you want your parent to look for the next one.
     *
     * This is equivalent to calling {@link #requestFocus(int, Rect)} with arguments
     * {@link #FOCUS_DOWN} and <code>null</code>.
     *
     * @return Whether this view or one of its descendants actually took focus.
     */
    public final boolean requestFocus() {
        return requestFocus(View.FOCUS_DOWN);
    }


    /**
     * Call this to try to give focus to a specific view or to one of its
     * descendants and give it a hint about what direction focus is heading.
     *
     * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns false),
     * or if it is focusable and it is not focusable in touch mode ({@link #isFocusableInTouchMode})
     * while the device is in touch mode.
     *
     * See also {@link #focusSearch}, which is what you call to say that you
     * have focus, and you want your parent to look for the next one.
     *
     * This is equivalent to calling {@link #requestFocus(int, Rect)} with
     * <code>null</code> set for the previously focused rectangle.
     *
     * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
     * @return Whether this view or one of its descendants actually took focus.
     */
    public final boolean requestFocus(int direction) {
        return requestFocus(direction, null);
    }

    /**
     * Call this to try to give focus to a specific view or to one of its descendants
     * and give it hints about the direction and a specific rectangle that the focus
     * is coming from.  The rectangle can help give larger views a finer grained hint
     * about where focus is coming from, and therefore, where to show selection, or
     * forward focus change internally.
     *
     * A view will not actually take focus if it is not focusable ({@link #isFocusable} returns false),
     * or if it is focusable and it is not focusable in touch mode ({@link #isFocusableInTouchMode})
     * while the device is in touch mode.
     *
     * A View will not take focus if it is not visible.
     *
     * A View will not take focus if one of its parents has {@link android.view.ViewGroup#getDescendantFocusability()}
     * equal to {@link ViewGroup#FOCUS_BLOCK_DESCENDANTS}.
     *
     * See also {@link #focusSearch}, which is what you call to say that you
     * have focus, and you want your parent to look for the next one.
     *
     * You may wish to override this method if your custom {@link View} has an internal
     * {@link View} that it wishes to forward the request to.
     *
     * @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
     * @param previouslyFocusedRect The rectangle (in this View's coordinate system)
     *        to give a finer grained hint about where focus is coming from.  May be null
     *        if there is no hint.
     * @return Whether this view or one of its descendants actually took focus.
     */
    public boolean requestFocus(int direction, Rect previouslyFocusedRect) {
        // need to be focusable
        if ((mViewFlags & FOCUSABLE_MASK) != FOCUSABLE ||
                (mViewFlags & VISIBILITY_MASK) != VISIBLE) {
            return false;
        }

        // need to be focusable in touch mode if in touch mode
        if (isInTouchMode() &&
                (FOCUSABLE_IN_TOUCH_MODE != (mViewFlags & FOCUSABLE_IN_TOUCH_MODE))) {
            return false;
        }

        // need to not have any parents blocking us
        if (hasAncestorThatBlocksDescendantFocus()) {
            return false;
        }

        handleFocusGainInternal(direction, previouslyFocusedRect);
        return true;
    }

    /**
     * Call this to try to give focus to a specific view or to one of its descendants. This is a
     * special variant of {@link #requestFocus() } that will allow views that are not focuable in
     * touch mode to request focus when they are touched.
     *
     * @return Whether this view or one of its descendants actually took focus.
     *
     * @see #isInTouchMode()
     *
     */
    public final boolean requestFocusFromTouch() {
        // Leave touch mode if we need to
        if (isInTouchMode()) {
            View root = getRootView();
            if (root != null) {
               ViewRoot viewRoot = (ViewRoot)root.getParent();
               if (viewRoot != null) {
                   viewRoot.ensureTouchMode(false);
               }
            }
        }
        return requestFocus(View.FOCUS_DOWN);
    }

    /**
     * @return Whether any ancestor of this view blocks descendant focus.
     */
    private boolean hasAncestorThatBlocksDescendantFocus() {
        ViewParent ancestor = mParent;
        while (ancestor instanceof ViewGroup) {
            final ViewGroup vgAncestor = (ViewGroup) ancestor;
            if (vgAncestor.getDescendantFocusability() == ViewGroup.FOCUS_BLOCK_DESCENDANTS) {
                return true;
            } else {
                ancestor = vgAncestor.getParent();
            }
        }
        return false;
    }

    /**
     * @hide
     */
    public void dispatchStartTemporaryDetach() {
        onStartTemporaryDetach();
    }

    /**
     * This is called when a container is going to temporarily detach a child, with
     * {@link ViewGroup#detachViewFromParent(View) ViewGroup.detachViewFromParent}.
     * It will either be followed by {@link #onFinishTemporaryDetach()} or
     * {@link #onDetachedFromWindow()} when the container is done.
     */
    public void onStartTemporaryDetach() {
        removeUnsetPressCallback();
        mPrivateFlags |= CANCEL_NEXT_UP_EVENT;
    }

    /**
     * @hide
     */
    public void dispatchFinishTemporaryDetach() {
        onFinishTemporaryDetach();
    }

    /**
     * Called after {@link #onStartTemporaryDetach} when the container is done
     * changing the view.
     */
    public void onFinishTemporaryDetach() {
    }

    /**
     * capture information of this view for later analysis: developement only
     * check dynamic switch to make sure we only dump view
     * when ViewDebug.SYSTEM_PROPERTY_CAPTURE_VIEW) is set
     */
    private static void captureViewInfo(String subTag, View v) {
        if (v == null || SystemProperties.getInt(ViewDebug.SYSTEM_PROPERTY_CAPTURE_VIEW, 0) == 0) {
            return;
        }
        ViewDebug.dumpCapturedView(subTag, v);
    }

    /**
     * Return the global {@link KeyEvent.DispatcherState KeyEvent.DispatcherState}
     * for this view's window.  Returns null if the view is not currently attached
     * to the window.  Normally you will not need to use this directly, but
     * just use the standard high-level event callbacks like {@link #onKeyDown}.
     */
    public KeyEvent.DispatcherState getKeyDispatcherState() {
        return mAttachInfo != null ? mAttachInfo.mKeyDispatchState : null;
    }

    /**
     * Dispatch a key event before it is processed by any input method
     * associated with the view hierarchy.  This can be used to intercept
     * key events in special situations before the IME consumes them; a
     * typical example would be handling the BACK key to update the application's
     * UI instead of allowing the IME to see it and close itself.
     *
     * @param event The key event to be dispatched.
     * @return True if the event was handled, false otherwise.
     */
    public boolean dispatchKeyEventPreIme(KeyEvent event) {
        return onKeyPreIme(event.getKeyCode(), event);
    }

    /**
     * Dispatch a key event to the next view on the focus path. This path runs
     * from the top of the view tree down to the currently focused view. If this
     * view has focus, it will dispatch to itself. Otherwise it will dispatch
     * the next node down the focus path. This method also fires any key
     * listeners.
     *
     * @param event The key event to be dispatched.
     * @return True if the event was handled, false otherwise.
     */
    public boolean dispatchKeyEvent(KeyEvent event) {
        // If any attached key listener a first crack at the event.
        //noinspection SimplifiableIfStatement

        if (android.util.Config.LOGV) {
            captureViewInfo("captureViewKeyEvent", this);
        }

        if (mOnKeyListener != null && (mViewFlags & ENABLED_MASK) == ENABLED
                && mOnKeyListener.onKey(this, event.getKeyCode(), event)) {
            return true;
        }

        return event.dispatch(this, mAttachInfo != null
                ? mAttachInfo.mKeyDispatchState : null, this);
    }

    /**
     * Dispatches a key shortcut event.
     *
     * @param event The key event to be dispatched.
     * @return True if the event was handled by the view, false otherwise.
     */
    public boolean dispatchKeyShortcutEvent(KeyEvent event) {
        return onKeyShortcut(event.getKeyCode(), event);
    }

    /**
     * Pass the touch screen motion event down to the target view, or this
     * view if it is the target.
     *
     * @param event The motion event to be dispatched.
     * @return True if the event was handled by the view, false otherwise.
     */
    public boolean dispatchTouchEvent(MotionEvent event) {
        if (!onFilterTouchEventForSecurity(event)) {
            return false;
        }

        if (mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED &&
                mOnTouchListener.onTouch(this, event)) {
            return true;
        }
        return onTouchEvent(event);
    }

    /**
     * Filter the touch event to apply security policies.
     *
     * @param event The motion event to be filtered.
     * @return True if the event should be dispatched, false if the event should be dropped.
     *
     * @see #getFilterTouchesWhenObscured
     */
    public boolean onFilterTouchEventForSecurity(MotionEvent event) {
        if ((mViewFlags & FILTER_TOUCHES_WHEN_OBSCURED) != 0
                && (event.getFlags() & MotionEvent.FLAG_WINDOW_IS_OBSCURED) != 0) {
            // Window is obscured, drop this touch.
            return false;
        }
        return true;
    }

    /**
     * Pass a trackball motion event down to the focused view.
     *
     * @param event The motion event to be dispatched.
     * @return True if the event was handled by the view, false otherwise.
     */
    public boolean dispatchTrackballEvent(MotionEvent event) {
        //Log.i("view", "view=" + this + ", " + event.toString());
        return onTrackballEvent(event);
    }

    /**
     * Called when the window containing this view gains or loses window focus.
     * ViewGroups should override to route to their children.
     *
     * @param hasFocus True if the window containing this view now has focus,
     *        false otherwise.
     */
    public void dispatchWindowFocusChanged(boolean hasFocus) {
        onWindowFocusChanged(hasFocus);
    }

    /**
     * Called when the window containing this view gains or loses focus.  Note
     * that this is separate from view focus: to receive key events, both
     * your view and its window must have focus.  If a window is displayed
     * on top of yours that takes input focus, then your own window will lose
     * focus but the view focus will remain unchanged.
     *
     * @param hasWindowFocus True if the window containing this view now has
     *        focus, false otherwise.
     */
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        InputMethodManager imm = InputMethodManager.peekInstance();
        if (!hasWindowFocus) {
            if (isPressed()) {
                setPressed(false);
            }
            if (imm != null && (mPrivateFlags & FOCUSED) != 0) {
                imm.focusOut(this);
            }
            removeLongPressCallback();
            onFocusLost();
        } else if (imm != null && (mPrivateFlags & FOCUSED) != 0) {
            imm.focusIn(this);
        }
        refreshDrawableState();
    }

    /**
     * Returns true if this view is in a window that currently has window focus.
     * Note that this is not the same as the view itself having focus.
     *
     * @return True if this view is in a window that currently has window focus.
     */
    public boolean hasWindowFocus() {
        return mAttachInfo != null && mAttachInfo.mHasWindowFocus;
    }

    /**
     * Dispatch a view visibility change down the view hierarchy.
     * ViewGroups should override to route to their children.
     * @param changedView The view whose visibility changed. Could be 'this' or
     * an ancestor view.
     * @param visibility The new visibility of changedView: {@link #VISIBLE},
     * {@link #INVISIBLE} or {@link #GONE}.
     */
    protected void dispatchVisibilityChanged(View changedView, int visibility) {
        onVisibilityChanged(changedView, visibility);
    }

    /**
     * Called when the visibility of the view or an ancestor of the view is changed.
     * @param changedView The view whose visibility changed. Could be 'this' or
     * an ancestor view.
     * @param visibility The new visibility of changedView: {@link #VISIBLE},
     * {@link #INVISIBLE} or {@link #GONE}.
     */
    protected void onVisibilityChanged(View changedView, int visibility) {
        if (visibility == VISIBLE) {
            if (mAttachInfo != null) {
                initialAwakenScrollBars();
            } else {
                mPrivateFlags |= AWAKEN_SCROLL_BARS_ON_ATTACH;
            }
        }
    }

    /**
     * Dispatch a hint about whether this view is displayed. For instance, when
     * a View moves out of the screen, it might receives a display hint indicating
     * the view is not displayed. Applications should not <em>rely</em> on this hint
     * as there is no guarantee that they will receive one.
     *
     * @param hint A hint about whether or not this view is displayed:
     * {@link #VISIBLE} or {@link #INVISIBLE}.
     */
    public void dispatchDisplayHint(int hint) {
        onDisplayHint(hint);
    }

    /**
     * Gives this view a hint about whether is displayed or not. For instance, when
     * a View moves out of the screen, it might receives a display hint indicating
     * the view is not displayed. Applications should not <em>rely</em> on this hint
     * as there is no guarantee that they will receive one.
     *
     * @param hint A hint about whether or not this view is displayed:
     * {@link #VISIBLE} or {@link #INVISIBLE}.
     */
    protected void onDisplayHint(int hint) {
    }

    /**
     * Dispatch a window visibility change down the view hierarchy.
     * ViewGroups should override to route to their children.
     *
     * @param visibility The new visibility of the window.
     *
     * @see #onWindowVisibilityChanged
     */
    public void dispatchWindowVisibilityChanged(int visibility) {
        onWindowVisibilityChanged(visibility);
    }

    /**
     * Called when the window containing has change its visibility
     * (between {@link #GONE}, {@link #INVISIBLE}, and {@link #VISIBLE}).  Note
     * that this tells you whether or not your window is being made visible
     * to the window manager; this does <em>not</em> tell you whether or not
     * your window is obscured by other windows on the screen, even if it
     * is itself visible.
     *
     * @param visibility The new visibility of the window.
     */
    protected void onWindowVisibilityChanged(int visibility) {
        if (visibility == VISIBLE) {
            initialAwakenScrollBars();
        }
    }

    /**
     * Returns the current visibility of the window this view is attached to
     * (either {@link #GONE}, {@link #INVISIBLE}, or {@link #VISIBLE}).
     *
     * @return Returns the current visibility of the view's window.
     */
    public int getWindowVisibility() {
        return mAttachInfo != null ? mAttachInfo.mWindowVisibility : GONE;
    }

    /**
     * Retrieve the overall visible display size in which the window this view is
     * attached to has been positioned in.  This takes into account screen
     * decorations above the window, for both cases where the window itself
     * is being position inside of them or the window is being placed under
     * then and covered insets are used for the window to position its content
     * inside.  In effect, this tells you the available area where content can
     * be placed and remain visible to users.
     *
     * <p>This function requires an IPC back to the window manager to retrieve
     * the requested information, so should not be used in performance critical
     * code like drawing.
     *
     * @param outRect Filled in with the visible display frame.  If the view
     * is not attached to a window, this is simply the raw display size.
     */
    public void getWindowVisibleDisplayFrame(Rect outRect) {
        if (mAttachInfo != null) {
            try {
                mAttachInfo.mSession.getDisplayFrame(mAttachInfo.mWindow, outRect);
            } catch (RemoteException e) {
                return;
            }
            // XXX This is really broken, and probably all needs to be done
            // in the window manager, and we need to know more about whether
            // we want the area behind or in front of the IME.
            final Rect insets = mAttachInfo.mVisibleInsets;
            outRect.left += insets.left;
            outRect.top += insets.top;
            outRect.right -= insets.right;
            outRect.bottom -= insets.bottom;
            return;
        }
        Display d = WindowManagerImpl.getDefault().getDefaultDisplay();
        outRect.set(0, 0, d.getWidth(), d.getHeight());
    }

    /**
     * Dispatch a notification about a resource configuration change down
     * the view hierarchy.
     * ViewGroups should override to route to their children.
     *
     * @param newConfig The new resource configuration.
     *
     * @see #onConfigurationChanged
     */
    public void dispatchConfigurationChanged(Configuration newConfig) {
        onConfigurationChanged(newConfig);
    }

    /**
     * Called when the current configuration of the resources being used
     * by the application have changed.  You can use this to decide when
     * to reload resources that can changed based on orientation and other
     * configuration characterstics.  You only need to use this if you are
     * not relying on the normal {@link android.app.Activity} mechanism of
     * recreating the activity instance upon a configuration change.
     *
     * @param newConfig The new resource configuration.
     */
    protected void onConfigurationChanged(Configuration newConfig) {
    }

    /**
     * Private function to aggregate all per-view attributes in to the view
     * root.
     */
    void dispatchCollectViewAttributes(int visibility) {
        performCollectViewAttributes(visibility);
    }

    void performCollectViewAttributes(int visibility) {
        //noinspection PointlessBitwiseExpression
        if (((visibility | mViewFlags) & (VISIBILITY_MASK | KEEP_SCREEN_ON))
                == (VISIBLE | KEEP_SCREEN_ON)) {
            mAttachInfo.mKeepScreenOn = true;
        }
    }

    void needGlobalAttributesUpdate(boolean force) {
        AttachInfo ai = mAttachInfo;
        if (ai != null) {
            if (ai.mKeepScreenOn || force) {
                ai.mRecomputeGlobalAttributes = true;
            }
        }
    }

    /**
     * Returns whether the device is currently in touch mode.  Touch mode is entered
     * once the user begins interacting with the device by touch, and affects various
     * things like whether focus is always visible to the user.
     *
     * @return Whether the device is in touch mode.
     */
    @ViewDebug.ExportedProperty
    public boolean isInTouchMode() {
        if (mAttachInfo != null) {
            return mAttachInfo.mInTouchMode;
        } else {
            return ViewRoot.isInTouchMode();
        }
    }

    /**
     * Returns the context the view is running in, through which it can
     * access the current theme, resources, etc.
     *
     * @return The view's Context.
     */
    @ViewDebug.CapturedViewProperty
    public final Context getContext() {
        return mContext;
    }

    /**
     * Handle a key event before it is processed by any input method
     * associated with the view hierarchy.  This can be used to intercept
     * key events in special situations before the IME consumes them; a
     * typical example would be handling the BACK key to update the application's
     * UI instead of allowing the IME to see it and close itself.
     *
     * @param keyCode The value in event.getKeyCode().
     * @param event Description of the key event.
     * @return If you handled the event, return true. If you want to allow the
     *         event to be handled by the next receiver, return false.
     */
    public boolean onKeyPreIme(int keyCode, KeyEvent event) {
        return false;
    }

    /**
     * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)
     * KeyEvent.Callback.onKeyMultiple()}: perform press of the view
     * when {@link KeyEvent#KEYCODE_DPAD_CENTER} or {@link KeyEvent#KEYCODE_ENTER}
     * is released, if the view is enabled and clickable.
     *
     * @param keyCode A key code that represents the button pressed, from
     *                {@link android.view.KeyEvent}.
     * @param event   The KeyEvent object that defines the button action.
     */
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        boolean result = false;

        switch (keyCode) {
            case KeyEvent.KEYCODE_DPAD_CENTER:
            case KeyEvent.KEYCODE_ENTER: {
                if ((mViewFlags & ENABLED_MASK) == DISABLED) {
                    return true;
                }
                // Long clickable items don't necessarily have to be clickable
                if (((mViewFlags & CLICKABLE) == CLICKABLE ||
                        (mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) &&
                        (event.getRepeatCount() == 0)) {
                    setPressed(true);
                    if ((mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) {
                        postCheckForLongClick(0);
                    }
                    return true;
                }
                break;
            }
        }
        return result;
    }

    /**
     * Default implementation of {@link KeyEvent.Callback#onKeyLongPress(int, KeyEvent)
     * KeyEvent.Callback.onKeyLongPress()}: always returns false (doesn't handle
     * the event).
     */
    public boolean onKeyLongPress(int keyCode, KeyEvent event) {
        return false;
    }

    /**
     * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)
     * KeyEvent.Callback.onKeyMultiple()}: perform clicking of the view
     * when {@link KeyEvent#KEYCODE_DPAD_CENTER} or
     * {@link KeyEvent#KEYCODE_ENTER} is released.
     *
     * @param keyCode A key code that represents the button pressed, from
     *                {@link android.view.KeyEvent}.
     * @param event   The KeyEvent object that defines the button action.
     */
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        boolean result = false;

        switch (keyCode) {
            case KeyEvent.KEYCODE_DPAD_CENTER:
            case KeyEvent.KEYCODE_ENTER: {
                if ((mViewFlags & ENABLED_MASK) == DISABLED) {
                    return true;
                }
                if ((mViewFlags & CLICKABLE) == CLICKABLE && isPressed()) {
                    setPressed(false);

                    if (!mHasPerformedLongPress) {
                        // This is a tap, so remove the longpress check
                        removeLongPressCallback();

                        result = performClick();
                    }
                }
                break;
            }
        }
        return result;
    }

    /**
     * Default implementation of {@link KeyEvent.Callback#onKeyMultiple(int, int, KeyEvent)
     * KeyEvent.Callback.onKeyMultiple()}: always returns false (doesn't handle
     * the event).
     *
     * @param keyCode     A key code that represents the button pressed, from
     *                    {@link android.view.KeyEvent}.
     * @param repeatCount The number of times the action was made.
     * @param event       The KeyEvent object that defines the button action.
     */
    public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) {
        return false;
    }

    /**
     * Called when an unhandled key shortcut event occurs.
     *
     * @param keyCode The value in event.getKeyCode().
     * @param event Description of the key event.
     * @return If you handled the event, return true. If you want to allow the
     *         event to be handled by the next receiver, return false.
     */
    public boolean onKeyShortcut(int keyCode, KeyEvent event) {
        return false;
    }

    /**
     * Check whether the called view is a text editor, in which case it
     * would make sense to automatically display a soft input window for
     * it.  Subclasses should override this if they implement
     * {@link #onCreateInputConnection(EditorInfo)} to return true if
     * a call on that method would return a non-null InputConnection, and
     * they are really a first-class editor that the user would normally
     * start typing on when the go into a window containing your view.
     *
     * <p>The default implementation always returns false.  This does
     * <em>not</em> mean that its {@link #onCreateInputConnection(EditorInfo)}
     * will not be called or the user can not otherwise perform edits on your
     * view; it is just a hint to the system that this is not the primary
     * purpose of this view.
     *
     * @return Returns true if this view is a text editor, else false.
     */
    public boolean onCheckIsTextEditor() {
        return false;
    }

    /**
     * Create a new InputConnection for an InputMethod to interact
     * with the view.  The default implementation returns null, since it doesn't
     * support input methods.  You can override this to implement such support.
     * This is only needed for views that take focus and text input.
     *
     * <p>When implementing this, you probably also want to implement
     * {@link #onCheckIsTextEditor()} to indicate you will return a
     * non-null InputConnection.
     *
     * @param outAttrs Fill in with attribute information about the connection.
     */
    public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
        return null;
    }

    /**
     * Called by the {@link android.view.inputmethod.InputMethodManager}
     * when a view who is not the current
     * input connection target is trying to make a call on the manager.  The
     * default implementation returns false; you can override this to return
     * true for certain views if you are performing InputConnection proxying
     * to them.
     * @param view The View that is making the InputMethodManager call.
     * @return Return true to allow the call, false to reject.
     */
    public boolean checkInputConnectionProxy(View view) {
        return false;
    }

    /**
     * Show the context menu for this view. It is not safe to hold on to the
     * menu after returning from this method.
     *
     * You should normally not overload this method. Overload
     * {@link #onCreateContextMenu(ContextMenu)} or define an
     * {@link OnCreateContextMenuListener} to add items to the context menu.
     *
     * @param menu The context menu to populate
     */
    public void createContextMenu(ContextMenu menu) {
        ContextMenuInfo menuInfo = getContextMenuInfo();

        // Sets the current menu info so all items added to menu will have
        // my extra info set.
        ((MenuBuilder)menu).setCurrentMenuInfo(menuInfo);

        onCreateContextMenu(menu);
        if (mOnCreateContextMenuListener != null) {
            mOnCreateContextMenuListener.onCreateContextMenu(menu, this, menuInfo);
        }

        // Clear the extra information so subsequent items that aren't mine don't
        // have my extra info.
        ((MenuBuilder)menu).setCurrentMenuInfo(null);

        if (mParent != null) {
            mParent.createContextMenu(menu);
        }
    }

    /**
     * Views should implement this if they have extra information to associate
     * with the context menu. The return result is supplied as a parameter to
     * the {@link OnCreateContextMenuListener#onCreateContextMenu(ContextMenu, View, ContextMenuInfo)}
     * callback.
     *
     * @return Extra information about the item for which the context menu
     *         should be shown. This information will vary across different
     *         subclasses of View.
     */
    protected ContextMenuInfo getContextMenuInfo() {
        return null;
    }

    /**
     * Views should implement this if the view itself is going to add items to
     * the context menu.
     *
     * @param menu the context menu to populate
     */
    protected void onCreateContextMenu(ContextMenu menu) {
    }

    /**
     * Implement this method to handle trackball motion events.  The
     * <em>relative</em> movement of the trackball since the last event
     * can be retrieve with {@link MotionEvent#getX MotionEvent.getX()} and
     * {@link MotionEvent#getY MotionEvent.getY()}.  These are normalized so
     * that a movement of 1 corresponds to the user pressing one DPAD key (so
     * they will often be fractional values, representing the more fine-grained
     * movement information available from a trackball).
     *
     * @param event The motion event.
     * @return True if the event was handled, false otherwise.
     */
    public boolean onTrackballEvent(MotionEvent event) {
        return false;
    }

    /**
     * Implement this method to handle touch screen motion events.
     *
     * @param event The motion event.
     * @return True if the event was handled, false otherwise.
     */
    public boolean onTouchEvent(MotionEvent event) {
        final int viewFlags = mViewFlags;

        if ((viewFlags & ENABLED_MASK) == DISABLED) {
            // A disabled view that is clickable still consumes the touch
            // events, it just doesn't respond to them.
            return (((viewFlags & CLICKABLE) == CLICKABLE ||
                    (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE));
        }

        if (mTouchDelegate != null) {
            if (mTouchDelegate.onTouchEvent(event)) {
                return true;
            }
        }

        if (((viewFlags & CLICKABLE) == CLICKABLE ||
                (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_UP:
                    boolean prepressed = (mPrivateFlags & PREPRESSED) != 0;
                    if ((mPrivateFlags & PRESSED) != 0 || prepressed) {
                        // take focus if we don't have it already and we should in
                        // touch mode.
                        boolean focusTaken = false;
                        if (isFocusable() && isFocusableInTouchMode() && !isFocused()) {
                            focusTaken = requestFocus();
                        }

                        if (!mHasPerformedLongPress) {
                            // This is a tap, so remove the longpress check
                            removeLongPressCallback();

                            // Only perform take click actions if we were in the pressed state
                            if (!focusTaken) {
                                // Use a Runnable and post this rather than calling
                                // performClick directly. This lets other visual state
                                // of the view update before click actions start.
                                if (mPerformClick == null) {
                                    mPerformClick = new PerformClick();
                                }
                                if (!post(mPerformClick)) {
                                    performClick();
                                }
                            }
                        }

                        if (mUnsetPressedState == null) {
                            mUnsetPressedState = new UnsetPressedState();
                        }

                        if (prepressed) {
                            mPrivateFlags |= PRESSED;
                            refreshDrawableState();
                            postDelayed(mUnsetPressedState,
                                    ViewConfiguration.getPressedStateDuration());
                        } else if (!post(mUnsetPressedState)) {
                            // If the post failed, unpress right now
                            mUnsetPressedState.run();
                        }
                        removeTapCallback();
                    }
                    break;

                case MotionEvent.ACTION_DOWN:
                    if (mPendingCheckForTap == null) {
                        mPendingCheckForTap = new CheckForTap();
                    }
                    mPrivateFlags |= PREPRESSED;
                    mHasPerformedLongPress = false;
                    postDelayed(mPendingCheckForTap, ViewConfiguration.getTapTimeout());
                    break;

                case MotionEvent.ACTION_CANCEL:
                    mPrivateFlags &= ~PRESSED;
                    refreshDrawableState();
                    removeTapCallback();
                    break;

                case MotionEvent.ACTION_MOVE:
                    final int x = (int) event.getX();
                    final int y = (int) event.getY();

                    // Be lenient about moving outside of buttons
                    int slop = mTouchSlop;
                    if ((x < 0 - slop) || (x >= getWidth() + slop) ||
                            (y < 0 - slop) || (y >= getHeight() + slop)) {
                        // Outside button
                        removeTapCallback();
                        if ((mPrivateFlags & PRESSED) != 0) {
                            // Remove any future long press/tap checks
                            removeLongPressCallback();

                            // Need to switch from pressed to not pressed
                            mPrivateFlags &= ~PRESSED;
                            refreshDrawableState();
                        }
                    }
                    break;
            }
            return true;
        }

        return false;
    }

    /**
     * Remove the longpress detection timer.
     */
    private void removeLongPressCallback() {
        if (mPendingCheckForLongPress != null) {
          removeCallbacks(mPendingCheckForLongPress);
        }
    }

    /**
     * Remove the prepress detection timer.
     */
    private void removeUnsetPressCallback() {
        if ((mPrivateFlags & PRESSED) != 0 && mUnsetPressedState != null) {
            setPressed(false);
            removeCallbacks(mUnsetPressedState);
        }
    }

    /**
     * Remove the tap detection timer.
     */
    private void removeTapCallback() {
        if (mPendingCheckForTap != null) {
            mPrivateFlags &= ~PREPRESSED;
            removeCallbacks(mPendingCheckForTap);
        }
    }

    /**
     * Cancels a pending long press.  Your subclass can use this if you
     * want the context menu to come up if the user presses and holds
     * at the same place, but you don't want it to come up if they press
     * and then move around enough to cause scrolling.
     */
    public void cancelLongPress() {
        removeLongPressCallback();

        /*
         * The prepressed state handled by the tap callback is a display
         * construct, but the tap callback will post a long press callback
         * less its own timeout. Remove it here.
         */
        removeTapCallback();
    }

    /**
     * Sets the TouchDelegate for this View.
     */
    public void setTouchDelegate(TouchDelegate delegate) {
        mTouchDelegate = delegate;
    }

    /**
     * Gets the TouchDelegate for this View.
     */
    public TouchDelegate getTouchDelegate() {
        return mTouchDelegate;
    }

    /**
     * Set flags controlling behavior of this view.
     *
     * @param flags Constant indicating the value which should be set
     * @param mask Constant indicating the bit range that should be changed
     */
    void setFlags(int flags, int mask) {
        int old = mViewFlags;
        mViewFlags = (mViewFlags & ~mask) | (flags & mask);

        int changed = mViewFlags ^ old;
        if (changed == 0) {
            return;
        }
        int privateFlags = mPrivateFlags;

        /* Check if the FOCUSABLE bit has changed */
        if (((changed & FOCUSABLE_MASK) != 0) &&
                ((privateFlags & HAS_BOUNDS) !=0)) {
            if (((old & FOCUSABLE_MASK) == FOCUSABLE)
                    && ((privateFlags & FOCUSED) != 0)) {
                /* Give up focus if we are no longer focusable */
                clearFocus();
            } else if (((old & FOCUSABLE_MASK) == NOT_FOCUSABLE)
                    && ((privateFlags & FOCUSED) == 0)) {
                /*
                 * Tell the view system that we are now available to take focus
                 * if no one else already has it.
                 */
                if (mParent != null) mParent.focusableViewAvailable(this);
            }
        }

        if ((flags & VISIBILITY_MASK) == VISIBLE) {
            if ((changed & VISIBILITY_MASK) != 0) {
                /*
                 * If this view is becoming visible, set the DRAWN flag so that
                 * the next invalidate() will not be skipped.
                 */
                mPrivateFlags |= DRAWN;

                needGlobalAttributesUpdate(true);

                // a view becoming visible is worth notifying the parent
                // about in case nothing has focus.  even if this specific view
                // isn't focusable, it may contain something that is, so let
                // the root view try to give this focus if nothing else does.
                if ((mParent != null) && (mBottom > mTop) && (mRight > mLeft)) {
                    mParent.focusableViewAvailable(this);
                }
            }
        }

        /* Check if the GONE bit has changed */
        if ((changed & GONE) != 0) {
            needGlobalAttributesUpdate(false);
            requestLayout();
            invalidate();

            if (((mViewFlags & VISIBILITY_MASK) == GONE)) {
                if (hasFocus()) clearFocus();
                destroyDrawingCache();
            }
            if (mAttachInfo != null) {
                mAttachInfo.mViewVisibilityChanged = true;
            }
        }

        /* Check if the VISIBLE bit has changed */
        if ((changed & INVISIBLE) != 0) {
            needGlobalAttributesUpdate(false);
            invalidate();

            if (((mViewFlags & VISIBILITY_MASK) == INVISIBLE) && hasFocus()) {
                // root view becoming invisible shouldn't clear focus
                if (getRootView() != this) {
                    clearFocus();
                }
            }
            if (mAttachInfo != null) {
                mAttachInfo.mViewVisibilityChanged = true;
            }
        }

        if ((changed & VISIBILITY_MASK) != 0) {
            dispatchVisibilityChanged(this, (flags & VISIBILITY_MASK));
        }

        if ((changed & WILL_NOT_CACHE_DRAWING) != 0) {
            destroyDrawingCache();
        }

        if ((changed & DRAWING_CACHE_ENABLED) != 0) {
            destroyDrawingCache();
            mPrivateFlags &= ~DRAWING_CACHE_VALID;
        }

        if ((changed & DRAWING_CACHE_QUALITY_MASK) != 0) {
            destroyDrawingCache();
            mPrivateFlags &= ~DRAWING_CACHE_VALID;
        }

        if ((changed & DRAW_MASK) != 0) {
            if ((mViewFlags & WILL_NOT_DRAW) != 0) {
                if (mBGDrawable != null) {
                    mPrivateFlags &= ~SKIP_DRAW;
                    mPrivateFlags |= ONLY_DRAWS_BACKGROUND;
                } else {
                    mPrivateFlags |= SKIP_DRAW;
                }
            } else {
                mPrivateFlags &= ~SKIP_DRAW;
            }
            requestLayout();
            invalidate();
        }

        if ((changed & KEEP_SCREEN_ON) != 0) {
            if (mParent != null) {
                mParent.recomputeViewAttributes(this);
            }
        }
    }

    /**
     * Change the view's z order in the tree, so it's on top of other sibling
     * views
     */
    public void bringToFront() {
        if (mParent != null) {
            mParent.bringChildToFront(this);
        }
    }

    /**
     * This is called in response to an internal scroll in this view (i.e., the
     * view scrolled its own contents). This is typically as a result of
     * {@link #scrollBy(int, int)} or {@link #scrollTo(int, int)} having been
     * called.
     *
     * @param l Current horizontal scroll origin.
     * @param t Current vertical scroll origin.
     * @param oldl Previous horizontal scroll origin.
     * @param oldt Previous vertical scroll origin.
     */
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        mBackgroundSizeChanged = true;

        final AttachInfo ai = mAttachInfo;
        if (ai != null) {
            ai.mViewScrollChanged = true;
        }
    }

    /**
     * This is called during layout when the size of this view has changed. If
     * you were just added to the view hierarchy, you're called with the old
     * values of 0.
     *
     * @param w Current width of this view.
     * @param h Current height of this view.
     * @param oldw Old width of this view.
     * @param oldh Old height of this view.
     */
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    }

    /**
     * Called by draw to draw the child views. This may be overridden
     * by derived classes to gain control just before its children are drawn
     * (but after its own view has been drawn).
     * @param canvas the canvas on which to draw the view
     */
    protected void dispatchDraw(Canvas canvas) {
    }

    /**
     * Gets the parent of this view. Note that the parent is a
     * ViewParent and not necessarily a View.
     *
     * @return Parent of this view.
     */
    public final ViewParent getParent() {
        return mParent;
    }

    /**
     * Return the scrolled left position of this view. This is the left edge of
     * the displayed part of your view. You do not need to draw any pixels
     * farther left, since those are outside of the frame of your view on
     * screen.
     *
     * @return The left edge of the displayed part of your view, in pixels.
     */
    public final int getScrollX() {
        return mScrollX;
    }

    /**
     * Return the scrolled top position of this view. This is the top edge of
     * the displayed part of your view. You do not need to draw any pixels above
     * it, since those are outside of the frame of your view on screen.
     *
     * @return The top edge of the displayed part of your view, in pixels.
     */
    public final int getScrollY() {
        return mScrollY;
    }

    /**
     * Return the width of the your view.
     *
     * @return The width of your view, in pixels.
     */
    @ViewDebug.ExportedProperty(category = "layout")
    public final int getWidth() {
        return mRight - mLeft;
    }

    /**
     * Return the height of your view.
     *
     * @return The height of your view, in pixels.
     */
    @ViewDebug.ExportedProperty(category = "layout")
    public final int getHeight() {
        return mBottom - mTop;
    }

    /**
     * Return the visible drawing bounds of your view. Fills in the output
     * rectangle with the values from getScrollX(), getScrollY(),
     * getWidth(), and getHeight().
     *
     * @param outRect The (scrolled) drawing bounds of the view.
     */
    public void getDrawingRect(Rect outRect) {
        outRect.left = mScrollX;
        outRect.top = mScrollY;
        outRect.right = mScrollX + (mRight - mLeft);
        outRect.bottom = mScrollY + (mBottom - mTop);
    }

    /**
     * The width of this view as measured in the most recent call to measure().
     * This should be used during measurement and layout calculations only. Use
     * {@link #getWidth()} to see how wide a view is after layout.
     *
     * @return The measured width of this view.
     */
    public final int getMeasuredWidth() {
        return mMeasuredWidth;
    }

    /**
     * The height of this view as measured in the most recent call to measure().
     * This should be used during measurement and layout calculations only. Use
     * {@link #getHeight()} to see how tall a view is after layout.
     *
     * @return The measured height of this view.
     */
    public final int getMeasuredHeight() {
        return mMeasuredHeight;
    }

    /**
     * Top position of this view relative to its parent.
     *
     * @return The top of this view, in pixels.
     */
    @ViewDebug.CapturedViewProperty
    public final int getTop() {
        return mTop;
    }

    /**
     * Bottom position of this view relative to its parent.
     *
     * @return The bottom of this view, in pixels.
     */
    @ViewDebug.CapturedViewProperty
    public final int getBottom() {
        return mBottom;
    }

    /**
     * Left position of this view relative to its parent.
     *
     * @return The left edge of this view, in pixels.
     */
    @ViewDebug.CapturedViewProperty
    public final int getLeft() {
        return mLeft;
    }

    /**
     * Right position of this view relative to its parent.
     *
     * @return The right edge of this view, in pixels.
     */
    @ViewDebug.CapturedViewProperty
    public final int getRight() {
        return mRight;
    }

    /**
     * Hit rectangle in parent's coordinates
     *
     * @param outRect The hit rectangle of the view.
     */
    public void getHitRect(Rect outRect) {
        outRect.set(mLeft, mTop, mRight, mBottom);
    }

    /**
     * When a view has focus and the user navigates away from it, the next view is searched for
     * starting from the rectangle filled in by this method.
     *
     * By default, the rectange is the {@link #getDrawingRect})of the view.  However, if your
     * view maintains some idea of internal selection, such as a cursor, or a selected row
     * or column, you should override this method and fill in a more specific rectangle.
     *
     * @param r The rectangle to fill in, in this view's coordinates.
     */
    public void getFocusedRect(Rect r) {
        getDrawingRect(r);
    }

    /**
     * If some part of this view is not clipped by any of its parents, then
     * return that area in r in global (root) coordinates. To convert r to local
     * coordinates, offset it by -globalOffset (e.g. r.offset(-globalOffset.x,
     * -globalOffset.y)) If the view is completely clipped or translated out,
     * return false.
     *
     * @param r If true is returned, r holds the global coordinates of the
     *        visible portion of this view.
     * @param globalOffset If true is returned, globalOffset holds the dx,dy
     *        between this view and its root. globalOffet may be null.
     * @return true if r is non-empty (i.e. part of the view is visible at the
     *         root level.
     */
    public boolean