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