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      1 /*
      2  * Copyright (C) 2013 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 com.android.systemui.recent;
     18 
     19 import android.animation.Animator;
     20 import android.animation.AnimatorListenerAdapter;
     21 import android.animation.ValueAnimator;
     22 import android.animation.Animator.AnimatorListener;
     23 import android.util.Log;
     24 import android.view.ViewTreeObserver;
     25 import android.view.View;
     26 import android.view.ViewPropertyAnimator;
     27 
     28 /*
     29  *  This is a helper class that listens to updates from the corresponding animation.
     30  *  For the first two frames, it adjusts the current play time of the animation to
     31  *  prevent jank at the beginning of the animation
     32  */
     33 public class FirstFrameAnimatorHelper implements ValueAnimator.AnimatorUpdateListener {
     34     private static final boolean DEBUG = false;
     35     private static final int MAX_DELAY = 1000;
     36     private static final int IDEAL_FRAME_DURATION = 16;
     37     private View mTarget;
     38     private long mStartFrame;
     39     private long mStartTime = -1;
     40     private boolean mHandlingOnAnimationUpdate;
     41     private boolean mAdjustedSecondFrameTime;
     42 
     43     private static ViewTreeObserver.OnDrawListener sGlobalDrawListener;
     44     private static long sGlobalFrameCounter;
     45 
     46     public FirstFrameAnimatorHelper(ValueAnimator animator, View target) {
     47         mTarget = target;
     48         animator.addUpdateListener(this);
     49     }
     50 
     51     public FirstFrameAnimatorHelper(ViewPropertyAnimator vpa, View target) {
     52         mTarget = target;
     53         vpa.setListener(new AnimatorListenerAdapter() {
     54                 public void onAnimationStart (Animator animation) {
     55                     final ValueAnimator va = (ValueAnimator) animation;
     56                     va.addUpdateListener(FirstFrameAnimatorHelper.this);
     57                     onAnimationUpdate(va);
     58                 }
     59             });
     60     }
     61 
     62     public static void initializeDrawListener(View view) {
     63         if (sGlobalDrawListener != null) {
     64             view.getViewTreeObserver().removeOnDrawListener(sGlobalDrawListener);
     65         }
     66         sGlobalDrawListener = new ViewTreeObserver.OnDrawListener() {
     67                 private long mTime = System.currentTimeMillis();
     68                 public void onDraw() {
     69                     sGlobalFrameCounter++;
     70                     if (DEBUG) {
     71                         long newTime = System.currentTimeMillis();
     72                         Log.d("FirstFrameAnimatorHelper", "TICK " + (newTime - mTime));
     73                         mTime = newTime;
     74                     }
     75                 }
     76             };
     77         view.getViewTreeObserver().addOnDrawListener(sGlobalDrawListener);
     78     }
     79 
     80     public void onAnimationUpdate(final ValueAnimator animation) {
     81         final long currentTime = System.currentTimeMillis();
     82         if (mStartTime == -1) {
     83             mStartFrame = sGlobalFrameCounter;
     84             mStartTime = currentTime;
     85         }
     86 
     87         if (!mHandlingOnAnimationUpdate) {
     88             mHandlingOnAnimationUpdate = true;
     89             long frameNum = sGlobalFrameCounter - mStartFrame;
     90             // If we haven't drawn our first frame, reset the time to t = 0
     91             // (give up after MAX_DELAY ms of waiting though - might happen, for example, if we
     92             // are no longer in the foreground and no frames are being rendered ever)
     93             if (frameNum == 0 && currentTime < mStartTime + MAX_DELAY) {
     94                 // The first frame on animations doesn't always trigger an invalidate...
     95                 // force an invalidate here to make sure the animation continues to advance
     96                 mTarget.getRootView().invalidate();
     97                 animation.setCurrentPlayTime(0);
     98 
     99             // For the second frame, if the first frame took more than 16ms,
    100             // adjust the start time and pretend it took only 16ms anyway. This
    101             // prevents a large jump in the animation due to an expensive first frame
    102             } else if (frameNum == 1 && currentTime < mStartTime + MAX_DELAY &&
    103                        !mAdjustedSecondFrameTime &&
    104                        currentTime > mStartTime + IDEAL_FRAME_DURATION) {
    105                 animation.setCurrentPlayTime(IDEAL_FRAME_DURATION);
    106                 mAdjustedSecondFrameTime = true;
    107             } else {
    108                 if (frameNum > 1) {
    109                     mTarget.post(new Runnable() {
    110                             public void run() {
    111                                 animation.removeUpdateListener(FirstFrameAnimatorHelper.this);
    112                             }
    113                         });
    114                 }
    115                 if (DEBUG) print(animation);
    116             }
    117             mHandlingOnAnimationUpdate = false;
    118         } else {
    119             if (DEBUG) print(animation);
    120         }
    121     }
    122 
    123     public void print(ValueAnimator animation) {
    124         float flatFraction = animation.getCurrentPlayTime() / (float) animation.getDuration();
    125         Log.d("FirstFrameAnimatorHelper", sGlobalFrameCounter +
    126               "(" + (sGlobalFrameCounter - mStartFrame) + ") " + mTarget + " dirty? " +
    127               mTarget.isDirty() + " " + flatFraction + " " + this + " " + animation);
    128     }
    129 }
    130