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}guide/topics/ui/controls/radiobutton.html">Radio Buttons</a>
38  * guide.</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 defStyleAttr)58     public RadioButton(Context context, AttributeSet attrs, int defStyleAttr) {
59         this(context, attrs, defStyleAttr, 0);
60     }
61 
RadioButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)62     public RadioButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
63         super(context, attrs, defStyleAttr, defStyleRes);
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
getAccessibilityClassName()81     public CharSequence getAccessibilityClassName() {
82         return RadioButton.class.getName();
83     }
84 }
85