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.AccessibilityNodeInfo;
22 
23 
24 /**
25  * <p>
26  * A radio button is a two-states button that can be either checked or
27  * unchecked. When the radio button is unchecked, the user can press or click it
28  * to check it. However, contrary to a {@link android.widget.CheckBox}, a radio
29  * button cannot be unchecked by the user once checked.
30  * </p>
31  *
32  * <p>
33  * Radio buttons are normally used together in a
34  * {@link android.widget.RadioGroup}. When several radio buttons live inside
35  * a radio group, checking one radio button unchecks all the others.</p>
36  * </p>
37  *
38  * <p>See the <a href="{@docRoot}guide/topics/ui/controls/radiobutton.html">Radio Buttons</a>
39  * guide.</p>
40  *
41  * <p><strong>XML attributes</strong></p>
42  * <p>
43  * See {@link android.R.styleable#CompoundButton CompoundButton Attributes},
44  * {@link android.R.styleable#Button Button Attributes},
45  * {@link android.R.styleable#TextView TextView Attributes},
46  * {@link android.R.styleable#View View Attributes}
47  * </p>
48  */
49 public class RadioButton extends CompoundButton {
50 
RadioButton(Context context)51     public RadioButton(Context context) {
52         this(context, null);
53     }
54 
RadioButton(Context context, AttributeSet attrs)55     public RadioButton(Context context, AttributeSet attrs) {
56         this(context, attrs, com.android.internal.R.attr.radioButtonStyle);
57     }
58 
RadioButton(Context context, AttributeSet attrs, int defStyleAttr)59     public RadioButton(Context context, AttributeSet attrs, int defStyleAttr) {
60         this(context, attrs, defStyleAttr, 0);
61     }
62 
RadioButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)63     public RadioButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
64         super(context, attrs, defStyleAttr, defStyleRes);
65     }
66 
67     /**
68      * {@inheritDoc}
69      * <p>
70      * If the radio button is already checked, this method will not toggle the radio button.
71      */
72     @Override
toggle()73     public void toggle() {
74         // we override to prevent toggle when the radio is already
75         // checked (as opposed to check boxes widgets)
76         if (!isChecked()) {
77             super.toggle();
78         }
79     }
80 
81     @Override
getAccessibilityClassName()82     public CharSequence getAccessibilityClassName() {
83         return RadioButton.class.getName();
84     }
85 
86     @Override
onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)87     public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
88         super.onInitializeAccessibilityNodeInfo(info);
89         if (getParent() instanceof RadioGroup) {
90             RadioGroup radioGroup = (RadioGroup) getParent();
91             if (radioGroup.getOrientation() == LinearLayout.HORIZONTAL) {
92                 info.setCollectionItemInfo(AccessibilityNodeInfo.CollectionItemInfo.obtain(0, 1,
93                         radioGroup.getIndexWithinVisibleButtons(this), 1, false, isChecked()));
94             } else {
95                 info.setCollectionItemInfo(AccessibilityNodeInfo.CollectionItemInfo.obtain(
96                         radioGroup.getIndexWithinVisibleButtons(this), 1, 0, 1,
97                         false, isChecked()));
98             }
99         }
100     }
101 }
102