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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.launcher3;
     18 
     19 import android.animation.Animator;
     20 import android.animation.AnimatorListenerAdapter;
     21 import android.animation.ValueAnimator;
     22 import android.util.Log;
     23 import android.view.View;
     24 import android.view.ViewPropertyAnimator;
     25 import android.view.ViewTreeObserver;
     26 
     27 /*
     28  *  This is a helper class that listens to updates from the corresponding animation.
     29  *  For the first two frames, it adjusts the current play time of the animation to
     30  *  prevent jank at the beginning of the animation
     31  */
     32 public class FirstFrameAnimatorHelper extends AnimatorListenerAdapter
     33     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     private static boolean sVisible;
     46 
     47     public FirstFrameAnimatorHelper(ValueAnimator animator, View target) {
     48         mTarget = target;
     49         animator.addUpdateListener(this);
     50     }
     51 
     52     public FirstFrameAnimatorHelper(ViewPropertyAnimator vpa, View target) {
     53         mTarget = target;
     54         vpa.setListener(this);
     55     }
     56 
     57     // only used for ViewPropertyAnimators
     58     public void onAnimationStart(Animator animation) {
     59         final ValueAnimator va = (ValueAnimator) animation;
     60         va.addUpdateListener(FirstFrameAnimatorHelper.this);
     61         onAnimationUpdate(va);
     62     }
     63 
     64     public static void setIsVisible(boolean visible) {
     65         sVisible = visible;
     66     }
     67 
     68     public static void initializeDrawListener(View view) {
     69         if (sGlobalDrawListener != null) {
     70             view.getViewTreeObserver().removeOnDrawListener(sGlobalDrawListener);
     71         }
     72         sGlobalDrawListener = new ViewTreeObserver.OnDrawListener() {
     73                 private long mTime = System.currentTimeMillis();
     74                 public void onDraw() {
     75                     sGlobalFrameCounter++;
     76                     if (DEBUG) {
     77                         long newTime = System.currentTimeMillis();
     78                         Log.d("FirstFrameAnimatorHelper", "TICK " + (newTime - mTime));
     79                         mTime = newTime;
     80                     }
     81                 }
     82             };
     83         view.getViewTreeObserver().addOnDrawListener(sGlobalDrawListener);
     84         sVisible = true;
     85     }
     86 
     87     public void onAnimationUpdate(final ValueAnimator animation) {
     88         final long currentTime = System.currentTimeMillis();
     89         if (mStartTime == -1) {
     90             mStartFrame = sGlobalFrameCounter;
     91             mStartTime = currentTime;
     92         }
     93 
     94         if (!mHandlingOnAnimationUpdate &&
     95             sVisible &&
     96             // If the current play time exceeds the duration, the animation
     97             // will get finished, even if we call setCurrentPlayTime -- therefore
     98             // don't adjust the animation in that case
     99             animation.getCurrentPlayTime() < animation.getDuration()) {
    100             mHandlingOnAnimationUpdate = true;
    101             long frameNum = sGlobalFrameCounter - mStartFrame;
    102             // If we haven't drawn our first frame, reset the time to t = 0
    103             // (give up after MAX_DELAY ms of waiting though - might happen, for example, if we
    104             // are no longer in the foreground and no frames are being rendered ever)
    105             if (frameNum == 0 && currentTime < mStartTime + MAX_DELAY) {
    106                 // The first frame on animations doesn't always trigger an invalidate...
    107                 // force an invalidate here to make sure the animation continues to advance
    108                 mTarget.getRootView().invalidate();
    109                 animation.setCurrentPlayTime(0);
    110 
    111             // For the second frame, if the first frame took more than 16ms,
    112             // adjust the start time and pretend it took only 16ms anyway. This
    113             // prevents a large jump in the animation due to an expensive first frame
    114             } else if (frameNum == 1 && currentTime < mStartTime + MAX_DELAY &&
    115                        !mAdjustedSecondFrameTime &&
    116                        currentTime > mStartTime + IDEAL_FRAME_DURATION) {
    117                 animation.setCurrentPlayTime(IDEAL_FRAME_DURATION);
    118                 mAdjustedSecondFrameTime = true;
    119             } else {
    120                 if (frameNum > 1) {
    121                     mTarget.post(new Runnable() {
    122                             public void run() {
    123                                 animation.removeUpdateListener(FirstFrameAnimatorHelper.this);
    124                             }
    125                         });
    126                 }
    127                 if (DEBUG) print(animation);
    128             }
    129             mHandlingOnAnimationUpdate = false;
    130         } else {
    131             if (DEBUG) print(animation);
    132         }
    133     }
    134 
    135     public void print(ValueAnimator animation) {
    136         float flatFraction = animation.getCurrentPlayTime() / (float) animation.getDuration();
    137         Log.d("FirstFrameAnimatorHelper", sGlobalFrameCounter +
    138               "(" + (sGlobalFrameCounter - mStartFrame) + ") " + mTarget + " dirty? " +
    139               mTarget.isDirty() + " " + flatFraction + " " + this + " " + animation);
    140     }
    141 }
    142