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 25 /** 26 * <p> 27 * A radio button is a two-states button that can be either checked or 28 * unchecked. When the radio button is unchecked, the user can press or click it 29 * to check it. However, contrary to a {@link android.widget.CheckBox}, a radio 30 * button cannot be unchecked by the user once checked. 31 * </p> 32 * 33 * <p> 34 * Radio buttons are normally used together in a 35 * {@link android.widget.RadioGroup}. When several radio buttons live inside 36 * a radio group, checking one radio button unchecks all the others.</p> 37 * </p> 38 * 39 * <p>See the <a href="{@docRoot}guide/topics/ui/controls/radiobutton.html">Radio Buttons</a> 40 * guide.</p> 41 * 42 * <p><strong>XML attributes</strong></p> 43 * <p> 44 * See {@link android.R.styleable#CompoundButton CompoundButton Attributes}, 45 * {@link android.R.styleable#Button Button Attributes}, 46 * {@link android.R.styleable#TextView TextView Attributes}, 47 * {@link android.R.styleable#View View Attributes} 48 * </p> 49 */ 50 public class RadioButton extends CompoundButton { 51 RadioButton(Context context)52 public RadioButton(Context context) { 53 this(context, null); 54 } 55 RadioButton(Context context, AttributeSet attrs)56 public RadioButton(Context context, AttributeSet attrs) { 57 this(context, attrs, com.android.internal.R.attr.radioButtonStyle); 58 } 59 RadioButton(Context context, AttributeSet attrs, int defStyleAttr)60 public RadioButton(Context context, AttributeSet attrs, int defStyleAttr) { 61 this(context, attrs, defStyleAttr, 0); 62 } 63 RadioButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)64 public RadioButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 65 super(context, attrs, defStyleAttr, defStyleRes); 66 } 67 68 /** 69 * {@inheritDoc} 70 * <p> 71 * If the radio button is already checked, this method will not toggle the radio button. 72 */ 73 @Override toggle()74 public void toggle() { 75 // we override to prevent toggle when the radio is already 76 // checked (as opposed to check boxes widgets) 77 if (!isChecked()) { 78 super.toggle(); 79 } 80 } 81 82 @Override onInitializeAccessibilityEvent(AccessibilityEvent event)83 public void onInitializeAccessibilityEvent(AccessibilityEvent event) { 84 super.onInitializeAccessibilityEvent(event); 85 event.setClassName(RadioButton.class.getName()); 86 } 87 88 @Override onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)89 public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { 90 super.onInitializeAccessibilityNodeInfo(info); 91 info.setClassName(RadioButton.class.getName()); 92 } 93 } 94