content: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.widget;
  
  import android.annotation.FloatRange;
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.graphics.drawable.Drawable;
  import android.graphics.drawable.LayerDrawable;
  import android.util.AttributeSet;
  import android.view.inspector.InspectableProperty;
  
  /**
   * Displays checked/unchecked states as a button
   * with a "light" indicator and by default accompanied with the text "ON" or "OFF".
   *
   * <p>See the <a href="{@docRoot}guide/topics/ui/controls/togglebutton.html">Toggle Buttons</a>
   * guide.</p>
   * 
   * @attr ref android.R.styleable#ToggleButton_textOn
   * @attr ref android.R.styleable#ToggleButton_textOff
   * @attr ref android.R.styleable#ToggleButton_disabledAlpha
   */
  public class ToggleButton extends CompoundButton {
      private CharSequence mTextOn;
      private CharSequence mTextOff;
      
      private Drawable mIndicatorDrawable;
  
      private static final int NO_ALPHA = 0xFF;
      private float mDisabledAlpha;
  
      public ToggleButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
          super(context, attrs, defStyleAttr, defStyleRes);
  
          final TypedArray a = context.obtainStyledAttributes(
                  attrs, com.android.internal.R.styleable.ToggleButton, defStyleAttr, defStyleRes);
          saveAttributeDataForStyleable(context, com.android.internal.R.styleable.ToggleButton,
                  attrs, a, defStyleAttr, defStyleRes);
          mTextOn = a.getText(com.android.internal.R.styleable.ToggleButton_textOn);
          mTextOff = a.getText(com.android.internal.R.styleable.ToggleButton_textOff);
          mDisabledAlpha = a.getFloat(com.android.internal.R.styleable.ToggleButton_disabledAlpha, 0.5f);
          syncTextState();
          a.recycle();
      }
  
      public ToggleButton(Context context, AttributeSet attrs, int defStyleAttr) {
          this(context, attrs, defStyleAttr, 0);
      }
  
      public ToggleButton(Context context, AttributeSet attrs) {
          this(context, attrs, com.android.internal.R.attr.buttonStyleToggle);
      }
  
      public ToggleButton(Context context) {
          this(context, null);
      }
  
      @Override
      public void setChecked(boolean checked) {
          super.setChecked(checked);
          
          syncTextState();
      }
  
      private void syncTextState() {
          boolean checked = isChecked();
          if (checked && mTextOn != null) {
              setText(mTextOn);
          } else if (!checked && mTextOff != null) {
              setText(mTextOff);
          }
      }
  
      /**
       * Returns the text for when the button is in the checked state.
       * 
       * @return The text.
       */
      @InspectableProperty
      public CharSequence getTextOn() {
          return mTextOn;
      }
  
      /**
       * Sets the text for when the button is in the checked state.
       *  
       * @param textOn The text.
       */
      public void setTextOn(CharSequence textOn) {
          mTextOn = textOn;
      }
  
      /**
       * Returns the text for when the button is not in the checked state.
       * 
       * @return The text.
       */
      @InspectableProperty
      public CharSequence getTextOff() {
          return mTextOff;
      }
  
      /**
       * Sets the text for when the button is not in the checked state.
       * 
       * @param textOff The text.
       */
      public void setTextOff(CharSequence textOff) {
          mTextOff = textOff;
      }
  
      /**
       * Returns the alpha value of the button when it is disabled
       *
       * @return the alpha value, 0.0-1.0
       */
      @InspectableProperty
      @FloatRange(from = 0.0, to = 1.0)
      public float getDisabledAlpha() {
          return mDisabledAlpha;
      }
  
      @Override
      protected void onFinishInflate() {
          super.onFinishInflate();
          
          updateReferenceToIndicatorDrawable(getBackground());
      }
  
      @Override
      public void setBackgroundDrawable(Drawable d) {
          super.setBackgroundDrawable(d);
          
          updateReferenceToIndicatorDrawable(d);
      }
  
      private void updateReferenceToIndicatorDrawable(Drawable backgroundDrawable) {
          if (backgroundDrawable instanceof LayerDrawable) {
              LayerDrawable layerDrawable = (LayerDrawable) backgroundDrawable;
              mIndicatorDrawable =
                      layerDrawable.findDrawableByLayerId(com.android.internal.R.id.toggle);
          } else {
              mIndicatorDrawable = null;
          }
      }
      
      @Override
      protected void drawableStateChanged() {
          super.drawableStateChanged();
          
          if (mIndicatorDrawable != null) {
              mIndicatorDrawable.setAlpha(isEnabled() ? NO_ALPHA : (int) (NO_ALPHA * mDisabledAlpha));
          }
      }
  
      @Override
      public CharSequence getAccessibilityClassName() {
          return ToggleButton.class.getName();
      }
  }
  