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 24 import com.android.internal.R; 25 26 27 /** 28 * <p> 29 * A radio button is a two-states button that can be either checked or 30 * unchecked. When the radio button is unchecked, the user can press or click it 31 * to check it. However, contrary to a {@link android.widget.CheckBox}, a radio 32 * button cannot be unchecked by the user once checked. 33 * </p> 34 * 35 * <p> 36 * Radio buttons are normally used together in a 37 * {@link android.widget.RadioGroup}. When several radio buttons live inside 38 * a radio group, checking one radio button unchecks all the others.</p> 39 * </p> 40 * 41 * <p>See the <a href="{@docRoot}guide/topics/ui/controls/radiobutton.html">Radio Buttons</a> 42 * guide.</p> 43 * 44 * <p><strong>XML attributes</strong></p> 45 * <p> 46 * See {@link android.R.styleable#CompoundButton CompoundButton Attributes}, 47 * {@link android.R.styleable#Button Button Attributes}, 48 * {@link android.R.styleable#TextView TextView Attributes}, 49 * {@link android.R.styleable#View View Attributes} 50 * </p> 51 */ 52 public class RadioButton extends CompoundButton { 53 RadioButton(Context context)54 public RadioButton(Context context) { 55 this(context, null); 56 } 57 RadioButton(Context context, AttributeSet attrs)58 public RadioButton(Context context, AttributeSet attrs) { 59 this(context, attrs, com.android.internal.R.attr.radioButtonStyle); 60 } 61 RadioButton(Context context, AttributeSet attrs, int defStyle)62 public RadioButton(Context context, AttributeSet attrs, int defStyle) { 63 super(context, attrs, defStyle); 64 } 65 66 /** 67 * {@inheritDoc} 68 * <p> 69 * If the radio button is already checked, this method will not toggle the radio button. 70 */ 71 @Override toggle()72 public void toggle() { 73 // we override to prevent toggle when the radio is already 74 // checked (as opposed to check boxes widgets) 75 if (!isChecked()) { 76 super.toggle(); 77 } 78 } 79 80 @Override onInitializeAccessibilityEvent(AccessibilityEvent event)81 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 82 super.onInitializeAccessibilityEvent(event); 83 event.setClassName(RadioButton.class.getName()); 84 } 85 86 @Override onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)87 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 88 super.onInitializeAccessibilityNodeInfo(info); 89 info.setClassName(RadioButton.class.getName()); 90 } 91 } 92