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.view.accessibility.AccessibilityEvent; 22 import android.view.accessibility.AccessibilityNodeInfo; 23 import android.widget.RemoteViews.RemoteView; 24 25 26 /** 27 * Represents a push-button widget. Push-buttons can be 28 * pressed, or clicked, by the user to perform an action. 29 30 * <p>A typical use of a push-button in an activity would be the following: 31 * </p> 32 * 33 * <pre> 34 * public class MyActivity extends Activity { 35 * protected void onCreate(Bundle icicle) { 36 * super.onCreate(icicle); 37 * 38 * setContentView(R.layout.content_layout_id); 39 * 40 * final Button button = (Button) findViewById(R.id.button_id); 41 * button.setOnClickListener(new View.OnClickListener() { 42 * public void onClick(View v) { 43 * // Perform action on click 44 * } 45 * }); 46 * } 47 * }</pre> 48 * 49 * <p>However, instead of applying an {@link android.view.View.OnClickListener OnClickListener} to 50 * the button in your activity, you can assign a method to your button in the XML layout, 51 * using the {@link android.R.attr#onClick android:onClick} attribute. For example:</p> 52 * 53 * <pre> 54 * <Button 55 * android:layout_height="wrap_content" 56 * android:layout_width="wrap_content" 57 * android:text="@string/self_destruct" 58 * android:onClick="selfDestruct" /></pre> 59 * 60 * <p>Now, when a user clicks the button, the Android system calls the activity's {@code 61 * selfDestruct(View)} method. In order for this to work, the method must be public and accept 62 * a {@link android.view.View} as its only parameter. For example:</p> 63 * 64 * <pre> 65 * public void selfDestruct(View view) { 66 * // Kabloey 67 * }</pre> 68 * 69 * <p>The {@link android.view.View} passed into the method is a reference to the widget 70 * that was clicked.</p> 71 * 72 * <h3>Button style</h3> 73 * 74 * <p>Every Button is styled using the system's default button background, which is often different 75 * from one device to another and from one version of the platform to another. If you're not 76 * satisfied with the default button style and want to customize it to match the design of your 77 * application, then you can replace the button's background image with a <a 78 * href="{@docRoot}guide/topics/resources/drawable-resource.html#StateList">state list drawable</a>. 79 * A state list drawable is a drawable resource defined in XML that changes its image based on 80 * the current state of the button. Once you've defined a state list drawable in XML, you can apply 81 * it to your Button with the {@link android.R.attr#background android:background} 82 * attribute. For more information and an example, see <a 83 * href="{@docRoot}guide/topics/resources/drawable-resource.html#StateList">State List 84 * Drawable</a>.</p> 85 * 86 * <p>Also see the <a href="{@docRoot}resources/tutorials/views/hello-formstuff.html">Form Stuff 87 * tutorial</a> for an example implementation of a button.</p> 88 * 89 * <p><strong>XML attributes</strong></p> 90 * <p> 91 * See {@link android.R.styleable#Button Button Attributes}, 92 * {@link android.R.styleable#TextView TextView Attributes}, 93 * {@link android.R.styleable#View View Attributes} 94 * </p> 95 */ 96 @RemoteView 97 public class Button extends TextView { Button(Context context)98 public Button(Context context) { 99 this(context, null); 100 } 101 Button(Context context, AttributeSet attrs)102 public Button(Context context, AttributeSet attrs) { 103 this(context, attrs, com.android.internal.R.attr.buttonStyle); 104 } 105 Button(Context context, AttributeSet attrs, int defStyle)106 public Button(Context context, AttributeSet attrs, int defStyle) { 107 super(context, attrs, defStyle); 108 } 109 110 @Override onInitializeAccessibilityEvent(AccessibilityEvent event)111 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 112 super.onInitializeAccessibilityEvent(event); 113 event.setClassName(Button.class.getName()); 114 } 115 116 @Override onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)117 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 118 super.onInitializeAccessibilityNodeInfo(info); 119 info.setClassName(Button.class.getName()); 120 } 121 } 122