2 * Copyright (C) 2006 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 package android.widget;
19 import android.content.Context;
20 import android.util.AttributeSet;
21 import android.view.MotionEvent;
22 import android.view.PointerIcon;
23 import android.widget.RemoteViews.RemoteView;
27 * Represents a push-button widget. Push-buttons can be
28 * pressed, or clicked, by the user to perform an action.
30 * <p>A typical use of a push-button in an activity would be the following:
34 * public class MyActivity extends Activity {
35 * protected void onCreate(Bundle icicle) {
36 * super.onCreate(icicle);
38 * setContentView(R.layout.content_layout_id);
40 * final Button button = findViewById(R.id.button_id);
41 * button.setOnClickListener(new View.OnClickListener() {
42 * public void onClick(View v) {
43 * // Perform action on click
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>
55 * android:layout_height="wrap_content"
56 * android:layout_width="wrap_content"
57 * android:text="@string/self_destruct"
58 * android:onClick="selfDestruct" /></pre>
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>
65 * public void selfDestruct(View view) {
69 * <p>The {@link android.view.View} passed into the method is a reference to the widget
70 * that was clicked.</p>
72 * <h3>Button style</h3>
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
86 * <p>See the <a href="{@docRoot}guide/topics/ui/controls/button.html">Buttons</a>
89 * <p><strong>XML attributes</strong></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}
97 public class Button extends TextView {
98 public Button(Context context) {
102 public Button(Context context, AttributeSet attrs) {
103 this(context, attrs, com.android.internal.R.attr.buttonStyle);
106 public Button(Context context, AttributeSet attrs, int defStyleAttr) {
107 this(context, attrs, defStyleAttr, 0);
110 public Button(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
111 super(context, attrs, defStyleAttr, defStyleRes);
115 public CharSequence getAccessibilityClassName() {
116 return Button.class.getName();
120 public PointerIcon onResolvePointerIcon(MotionEvent event, int pointerIndex) {
121 if (getPointerIcon() == null && isClickable() && isEnabled()) {
122 return PointerIcon.getSystemIcon(getContext(), PointerIcon.TYPE_HAND);
124 return super.onResolvePointerIcon(event, pointerIndex);