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      1 /*
      2  * Copyright (C) 2007 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.content.res.TypedArray;
     21 import android.graphics.drawable.Drawable;
     22 import android.graphics.drawable.LayerDrawable;
     23 import android.util.AttributeSet;
     24 import android.view.accessibility.AccessibilityEvent;
     25 import android.view.accessibility.AccessibilityNodeInfo;
     26 
     27 /**
     28  * Displays checked/unchecked states as a button
     29  * with a "light" indicator and by default accompanied with the text "ON" or "OFF".
     30  *
     31  * <p>See the <a href="{@docRoot}guide/topics/ui/controls/togglebutton.html">Toggle Buttons</a>
     32  * guide.</p>
     33  *
     34  * @attr ref android.R.styleable#ToggleButton_textOn
     35  * @attr ref android.R.styleable#ToggleButton_textOff
     36  * @attr ref android.R.styleable#ToggleButton_disabledAlpha
     37  */
     38 public class ToggleButton extends CompoundButton {
     39     private CharSequence mTextOn;
     40     private CharSequence mTextOff;
     41 
     42     private Drawable mIndicatorDrawable;
     43 
     44     private static final int NO_ALPHA = 0xFF;
     45     private float mDisabledAlpha;
     46 
     47     public ToggleButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
     48         super(context, attrs, defStyleAttr, defStyleRes);
     49 
     50         final TypedArray a = context.obtainStyledAttributes(
     51                 attrs, com.android.internal.R.styleable.ToggleButton, defStyleAttr, defStyleRes);
     52         mTextOn = a.getText(com.android.internal.R.styleable.ToggleButton_textOn);
     53         mTextOff = a.getText(com.android.internal.R.styleable.ToggleButton_textOff);
     54         mDisabledAlpha = a.getFloat(com.android.internal.R.styleable.ToggleButton_disabledAlpha, 0.5f);
     55         syncTextState();
     56         a.recycle();
     57     }
     58 
     59     public ToggleButton(Context context, AttributeSet attrs, int defStyleAttr) {
     60         this(context, attrs, defStyleAttr, 0);
     61     }
     62 
     63     public ToggleButton(Context context, AttributeSet attrs) {
     64         this(context, attrs, com.android.internal.R.attr.buttonStyleToggle);
     65     }
     66 
     67     public ToggleButton(Context context) {
     68         this(context, null);
     69     }
     70 
     71     @Override
     72     public void setChecked(boolean checked) {
     73         super.setChecked(checked);
     74 
     75         syncTextState();
     76     }
     77 
     78     private void syncTextState() {
     79         boolean checked = isChecked();
     80         if (checked && mTextOn != null) {
     81             setText(mTextOn);
     82         } else if (!checked && mTextOff != null) {
     83             setText(mTextOff);
     84         }
     85     }
     86 
     87     /**
     88      * Returns the text for when the button is in the checked state.
     89      *
     90      * @return The text.
     91      */
     92     public CharSequence getTextOn() {
     93         return mTextOn;
     94     }
     95 
     96     /**
     97      * Sets the text for when the button is in the checked state.
     98      *
     99      * @param textOn The text.
    100      */
    101     public void setTextOn(CharSequence textOn) {
    102         mTextOn = textOn;
    103     }
    104 
    105     /**
    106      * Returns the text for when the button is not in the checked state.
    107      *
    108      * @return The text.
    109      */
    110     public CharSequence getTextOff() {
    111         return mTextOff;
    112     }
    113 
    114     /**
    115      * Sets the text for when the button is not in the checked state.
    116      *
    117      * @param textOff The text.
    118      */
    119     public void setTextOff(CharSequence textOff) {
    120         mTextOff = textOff;
    121     }
    122 
    123     @Override
    124     protected void onFinishInflate() {
    125         super.onFinishInflate();
    126 
    127         updateReferenceToIndicatorDrawable(getBackground());
    128     }
    129 
    130     @Override
    131     public void setBackgroundDrawable(Drawable d) {
    132         super.setBackgroundDrawable(d);
    133 
    134         updateReferenceToIndicatorDrawable(d);
    135     }
    136 
    137     private void updateReferenceToIndicatorDrawable(Drawable backgroundDrawable) {
    138         if (backgroundDrawable instanceof LayerDrawable) {
    139             LayerDrawable layerDrawable = (LayerDrawable) backgroundDrawable;
    140             mIndicatorDrawable =
    141                     layerDrawable.findDrawableByLayerId(com.android.internal.R.id.toggle);
    142         } else {
    143             mIndicatorDrawable = null;
    144         }
    145     }
    146 
    147     @Override
    148     protected void drawableStateChanged() {
    149         super.drawableStateChanged();
    150 
    151         if (mIndicatorDrawable != null) {
    152             mIndicatorDrawable.setAlpha(isEnabled() ? NO_ALPHA : (int) (NO_ALPHA * mDisabledAlpha));
    153         }
    154     }
    155 
    156     @Override
    157     public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
    158         super.onInitializeAccessibilityEvent(event);
    159         event.setClassName(ToggleButton.class.getName());
    160     }
    161 
    162     @Override
    163     public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
    164         super.onInitializeAccessibilityNodeInfo(info);
    165         info.setClassName(ToggleButton.class.getName());
    166     }
    167 }
    168