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      1 /*
      2  * Copyright (C) 2006 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.widget;
     18 
     19 import android.content.Context;
     20 import android.util.AttributeSet;
     21 import android.util.Log;
     22 import android.view.MotionEvent;
     23 import android.view.KeyEvent;
     24 import android.widget.RemoteViews.RemoteView;
     25 
     26 
     27 /**
     28  * Represents a push-button widget. Push-buttons can be
     29  * pressed, or clicked, by the user to perform an action.
     30 
     31  * <p>A typical use of a push-button in an activity would be the following:
     32  * </p>
     33  *
     34  * <pre>
     35  * public class MyActivity extends Activity {
     36  *     protected void onCreate(Bundle icicle) {
     37  *         super.onCreate(icicle);
     38  *
     39  *         setContentView(R.layout.content_layout_id);
     40  *
     41  *         final Button button = (Button) findViewById(R.id.button_id);
     42  *         button.setOnClickListener(new View.OnClickListener() {
     43  *             public void onClick(View v) {
     44  *                 // Perform action on click
     45  *             }
     46  *         });
     47  *     }
     48  * }</pre>
     49  *
     50  * <p>However, instead of applying an {@link android.view.View.OnClickListener OnClickListener} to
     51  * the button in your activity, you can assign a method to your button in the XML layout,
     52  * using the {@link android.R.attr#onClick android:onClick} attribute. For example:</p>
     53  *
     54  * <pre>
     55  * &lt;Button
     56  *     android:layout_height="wrap_content"
     57  *     android:layout_width="wrap_content"
     58  *     android:text="@string/self_destruct"
     59  *     android:onClick="selfDestruct" /&gt;</pre>
     60  *
     61  * <p>Now, when a user clicks the button, the Android system calls the activity's {@code
     62  * selfDestruct(View)} method. In order for this to work, the method must be public and accept
     63  * a {@link android.view.View} as its only parameter. For example:</p>
     64  *
     65  * <pre>
     66  * public void selfDestruct(View view) {
     67  *     // Kabloey
     68  * }</pre>
     69  *
     70  * <p>The {@link android.view.View} passed into the method is a reference to the widget
     71  * that was clicked.</p>
     72  *
     73  * <h3>Button style</h3>
     74  *
     75  * <p>Every Button is styled using the system's default button background, which is often different
     76  * from one device to another and from one version of the platform to another. If you're not
     77  * satisfied with the default button style and want to customize it to match the design of your
     78  * application, then you can replace the button's background image with a <a
     79  * href="{@docRoot}guide/topics/resources/drawable-resource.html#StateList">state list drawable</a>.
     80  * A state list drawable is a drawable resource defined in XML that changes its image based on
     81  * the current state of the button. Once you've defined a state list drawable in XML, you can apply
     82  * it to your Button with the {@link android.R.attr#background android:background}
     83  * attribute. For more information and an example, see <a
     84  * href="{@docRoot}guide/topics/resources/drawable-resource.html#StateList">State List
     85  * Drawable</a>.</p>
     86  *
     87  * <p>Also see the <a href="{@docRoot}resources/tutorials/views/hello-formstuff.html">Form Stuff
     88  * tutorial</a> for an example implementation of a button.</p>
     89  *
     90  * <p><strong>XML attributes</strong></p>
     91  * <p>
     92  * See {@link android.R.styleable#Button Button Attributes},
     93  * {@link android.R.styleable#TextView TextView Attributes},
     94  * {@link android.R.styleable#View View Attributes}
     95  * </p>
     96  */
     97 @RemoteView
     98 public class Button extends TextView {
     99     public Button(Context context) {
    100         this(context, null);
    101     }
    102 
    103     public Button(Context context, AttributeSet attrs) {
    104         this(context, attrs, com.android.internal.R.attr.buttonStyle);
    105     }
    106 
    107     public Button(Context context, AttributeSet attrs, int defStyle) {
    108         super(context, attrs, defStyle);
    109     }
    110 }
    111