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 
FirstFrameAnimatorHelper(ValueAnimator animator, View target)49     public FirstFrameAnimatorHelper(ValueAnimator animator, View target) {
50         mTarget = target;
51         animator.addUpdateListener(this);
52     }
53 
FirstFrameAnimatorHelper(ViewPropertyAnimator vpa, View target)54     public FirstFrameAnimatorHelper(ViewPropertyAnimator vpa, View target) {
55         mTarget = target;
56         vpa.setListener(this);
57     }
58 
59     // only used for ViewPropertyAnimators
onAnimationStart(Animator animation)60     public void onAnimationStart(Animator animation) {
61         final ValueAnimator va = (ValueAnimator) animation;
62         va.addUpdateListener(FirstFrameAnimatorHelper.this);
63         onAnimationUpdate(va);
64     }
65 
setIsVisible(boolean visible)66     public static void setIsVisible(boolean visible) {
67         sVisible = visible;
68     }
69 
initializeDrawListener(View view)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 
onAnimationUpdate(final ValueAnimator animation)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 
print(ValueAnimator animation)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