content: /*
   * Copyright (C) 2018 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 com.android.launcher3.anim;
  
  import android.animation.Animator;
  import android.animation.ValueAnimator;
  import android.animation.ValueAnimator.AnimatorUpdateListener;
  import android.view.View;
  import android.view.ViewGroup;
  
  /**
   * A convenience class to update a view's visibility state after an alpha animation.
   */
  public class AlphaUpdateListener extends AnimationSuccessListener
          implements AnimatorUpdateListener {
      public static final float ALPHA_CUTOFF_THRESHOLD = 0.01f;
  
      private View mView;
  
      public AlphaUpdateListener(View v) {
          mView = v;
      }
  
      @Override
      public void onAnimationUpdate(ValueAnimator arg0) {
          updateVisibility(mView);
      }
  
      @Override
      public void onAnimationSuccess(Animator animator) {
          updateVisibility(mView);
      }
  
      @Override
      public void onAnimationStart(Animator arg0) {
          // We want the views to be visible for animation, so fade-in/out is visible
          mView.setVisibility(View.VISIBLE);
      }
  
      public static void updateVisibility(View view) {
          if (view.getAlpha() < ALPHA_CUTOFF_THRESHOLD && view.getVisibility() != View.INVISIBLE) {
              view.setVisibility(View.INVISIBLE);
          } else if (view.getAlpha() > ALPHA_CUTOFF_THRESHOLD
                  && view.getVisibility() != View.VISIBLE) {
              if (view instanceof ViewGroup) {
                  ViewGroup viewGroup = ((ViewGroup) view);
                  int oldFocusability = viewGroup.getDescendantFocusability();
                  viewGroup.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
                  viewGroup.setVisibility(View.VISIBLE);
                  viewGroup.setDescendantFocusability(oldFocusability);
              } else {
                  view.setVisibility(View.VISIBLE);
              }
          }
      }
  }