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 22 23 /** 24 * <p> 25 * A radio button is a two-states button that can be either checked or 26 * unchecked. When the radio button is unchecked, the user can press or click it 27 * to check it. However, contrary to a {@link android.widget.CheckBox}, a radio 28 * button cannot be unchecked by the user once checked. 29 * </p> 30 * 31 * <p> 32 * Radio buttons are normally used together in a 33 * {@link android.widget.RadioGroup}. When several radio buttons live inside 34 * a radio group, checking one radio button unchecks all the others.</p> 35 * </p> 36 * 37 * <p>See the <a href="{@docRoot}resources/tutorials/views/hello-formstuff.html">Form Stuff 38 * tutorial</a>.</p> 39 * 40 * <p><strong>XML attributes</strong></p> 41 * <p> 42 * See {@link android.R.styleable#CompoundButton CompoundButton Attributes}, 43 * {@link android.R.styleable#Button Button Attributes}, 44 * {@link android.R.styleable#TextView TextView Attributes}, 45 * {@link android.R.styleable#View View Attributes} 46 * </p> 47 */ 48 public class RadioButton extends CompoundButton { 49 RadioButton(Context context)50 public RadioButton(Context context) { 51 this(context, null); 52 } 53 RadioButton(Context context, AttributeSet attrs)54 public RadioButton(Context context, AttributeSet attrs) { 55 this(context, attrs, com.android.internal.R.attr.radioButtonStyle); 56 } 57 RadioButton(Context context, AttributeSet attrs, int defStyle)58 public RadioButton(Context context, AttributeSet attrs, int defStyle) { 59 super(context, attrs, defStyle); 60 } 61 62 /** 63 * {@inheritDoc} 64 * <p> 65 * If the radio button is already checked, this method will not toggle the radio button. 66 */ 67 @Override toggle()68 public void toggle() { 69 // we override to prevent toggle when the radio is already 70 // checked (as opposed to check boxes widgets) 71 if (!isChecked()) { 72 super.toggle(); 73 } 74 } 75 } 76