content: /*
   * Copyright (C) 2017 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.quickstep;
  
  import android.animation.Animator;
  import android.animation.AnimatorListenerAdapter;
  import android.animation.ObjectAnimator;
  import android.util.FloatProperty;
  
  /**
   * A mutable float which allows animating the value
   */
  public class AnimatedFloat {
  
      public static FloatProperty<AnimatedFloat> VALUE = new FloatProperty<AnimatedFloat>("value") {
          @Override
          public void setValue(AnimatedFloat obj, float v) {
              obj.updateValue(v);
          }
  
          @Override
          public Float get(AnimatedFloat obj) {
              return obj.value;
          }
      };
  
      private final Runnable mUpdateCallback;
      private ObjectAnimator mValueAnimator;
  
      public float value;
  
      public AnimatedFloat(Runnable updateCallback) {
          mUpdateCallback = updateCallback;
      }
  
      public ObjectAnimator animateToValue(float start, float end) {
          cancelAnimation();
          mValueAnimator = ObjectAnimator.ofFloat(this, VALUE, start, end);
          mValueAnimator.addListener(new AnimatorListenerAdapter() {
              @Override
              public void onAnimationEnd(Animator animator) {
                  if (mValueAnimator == animator) {
                      mValueAnimator = null;
                  }
              }
          });
          return mValueAnimator;
      }
  
      /**
       * Changes the value and calls the callback.
       * Note that the value can be directly accessed as well to avoid notifying the callback.
       */
      public void updateValue(float v) {
          if (Float.compare(v, value) != 0) {
              value = v;
              mUpdateCallback.run();
          }
      }
  
      public void cancelAnimation() {
          if (mValueAnimator != null) {
              mValueAnimator.cancel();
          }
      }
  
      public void finishAnimation() {
          if (mValueAnimator != null && mValueAnimator.isRunning()) {
              mValueAnimator.end();
          }
      }
  
      public ObjectAnimator getCurrentAnimation() {
          return mValueAnimator;
      }
  }
  