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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 import com.android.launcher3.util.Thunk;
     28 
     29 /*
     30  *  This is a helper class that listens to updates from the corresponding animation.
     31  *  For the first two frames, it adjusts the current play time of the animation to
     32  *  prevent jank at the beginning of the animation
     33  */
     34 public class FirstFrameAnimatorHelper extends AnimatorListenerAdapter
     35     implements ValueAnimator.AnimatorUpdateListener {
     36     private static final boolean DEBUG = false;
     37     private static final int MAX_DELAY = 1000;
     38     private static final int IDEAL_FRAME_DURATION = 16;
     39     private View mTarget;
     40     private long mStartFrame;
     41     private long mStartTime = -1;
     42     private boolean mHandlingOnAnimationUpdate;
     43     private boolean mAdjustedSecondFrameTime;
     44 
     45     private static ViewTreeObserver.OnDrawListener sGlobalDrawListener;
     46     @Thunk static long sGlobalFrameCounter;
     47     private static boolean sVisible;
     48 
     49     public FirstFrameAnimatorHelper(ValueAnimator animator, View target) {
     50         mTarget = target;
     51         animator.addUpdateListener(this);
     52     }
     53 
     54     public FirstFrameAnimatorHelper(ViewPropertyAnimator vpa, View target) {
     55         mTarget = target;
     56         vpa.setListener(this);
     57     }
     58 
     59     // only used for ViewPropertyAnimators
     60     public void onAnimationStart(Animator animation) {
     61         final ValueAnimator va = (ValueAnimator) animation;
     62         va.addUpdateListener(FirstFrameAnimatorHelper.this);
     63         onAnimationUpdate(va);
     64     }
     65 
     66     public static void setIsVisible(boolean visible) {
     67         sVisible = visible;
     68     }
     69 
     70     public static void initializeDrawListener(View view) {
     71         if (sGlobalDrawListener != null) {
     72             view.getViewTreeObserver().removeOnDrawListener(sGlobalDrawListener);
     73         }
     74         sGlobalDrawListener = new ViewTreeObserver.OnDrawListener() {
     75                 private long mTime = System.currentTimeMillis();
     76                 public void onDraw() {
     77                     sGlobalFrameCounter++;
     78                     if (DEBUG) {
     79                         long newTime = System.currentTimeMillis();
     80                         Log.d("FirstFrameAnimatorHelper", "TICK " + (newTime - mTime));
     81                         mTime = newTime;
     82                     }
     83                 }
     84             };
     85         view.getViewTreeObserver().addOnDrawListener(sGlobalDrawListener);
     86         sVisible = true;
     87     }
     88 
     89     public void onAnimationUpdate(final ValueAnimator animation) {
     90         final long currentTime = System.currentTimeMillis();
     91         if (mStartTime == -1) {
     92             mStartFrame = sGlobalFrameCounter;
     93             mStartTime = currentTime;
     94         }
     95 
     96         final long currentPlayTime = animation.getCurrentPlayTime();
     97         boolean isFinalFrame = Float.compare(1f, animation.getAnimatedFraction()) == 0;
     98 
     99         if (!mHandlingOnAnimationUpdate &&
    100             sVisible &&
    101             // If the current play time exceeds the duration, or the animated fraction is 1,
    102             // the animation will get finished, even if we call setCurrentPlayTime -- therefore
    103             // don't adjust the animation in that case
    104             currentPlayTime < animation.getDuration() && !isFinalFrame) {
    105             mHandlingOnAnimationUpdate = true;
    106             long frameNum = sGlobalFrameCounter - mStartFrame;
    107             // If we haven't drawn our first frame, reset the time to t = 0
    108             // (give up after MAX_DELAY ms of waiting though - might happen, for example, if we
    109             // are no longer in the foreground and no frames are being rendered ever)
    110             if (frameNum == 0 && currentTime < mStartTime + MAX_DELAY && currentPlayTime > 0) {
    111                 // The first frame on animations doesn't always trigger an invalidate...
    112                 // force an invalidate here to make sure the animation continues to advance
    113                 mTarget.getRootView().invalidate();
    114                 animation.setCurrentPlayTime(0);
    115             // For the second frame, if the first frame took more than 16ms,
    116             // adjust the start time and pretend it took only 16ms anyway. This
    117             // prevents a large jump in the animation due to an expensive first frame
    118             } else if (frameNum == 1 && currentTime < mStartTime + MAX_DELAY &&
    119                        !mAdjustedSecondFrameTime &&
    120                        currentTime > mStartTime + IDEAL_FRAME_DURATION &&
    121                        currentPlayTime > IDEAL_FRAME_DURATION) {
    122                 animation.setCurrentPlayTime(IDEAL_FRAME_DURATION);
    123                 mAdjustedSecondFrameTime = true;
    124             } else {
    125                 if (frameNum > 1) {
    126                     mTarget.post(new Runnable() {
    127                             public void run() {
    128                                 animation.removeUpdateListener(FirstFrameAnimatorHelper.this);
    129                             }
    130                         });
    131                 }
    132                 if (DEBUG) print(animation);
    133             }
    134             mHandlingOnAnimationUpdate = false;
    135         } else {
    136             if (DEBUG) print(animation);
    137         }
    138     }
    139 
    140     public void print(ValueAnimator animation) {
    141         float flatFraction = animation.getCurrentPlayTime() / (float) animation.getDuration();
    142         Log.d("FirstFrameAnimatorHelper", sGlobalFrameCounter +
    143               "(" + (sGlobalFrameCounter - mStartFrame) + ") " + mTarget + " dirty? " +
    144               mTarget.isDirty() + " " + flatFraction + " " + this + " " + animation);
    145     }
    146 }
    147