| /* |
| * 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 android.support.animation; |
| |
| import android.os.SystemClock; |
| import android.support.v4.util.SimpleArrayMap; |
| import android.view.Choreographer; |
| |
| import java.util.ArrayList; |
| |
| /** |
| * This custom, static handler handles the timing pulse that is shared by all active |
| * ValueAnimators. This approach ensures that the setting of animation values will happen on the |
| * same thread that animations start on, and that all animations will share the same times for |
| * calculating their values, which makes synchronizing animations possible. |
| * |
| * The handler uses the Choreographer by default for doing periodic callbacks. A custom |
| * AnimationFrameCallbackProvider can be set on the handler to provide timing pulse that |
| * may be independent of UI frame update. This could be useful in testing. |
| * |
| * @hide |
| */ |
| class AnimationHandler { |
| /** |
| * Callbacks that receives notifications for animation timing |
| */ |
| interface AnimationFrameCallback { |
| /** |
| * Run animation based on the frame time. |
| * @param frameTime The frame start time |
| */ |
| boolean doAnimationFrame(long frameTime); |
| } |
| |
| /** |
| * Internal per-thread collections used to avoid set collisions as animations start and end |
| * while being processed. |
| * @hide |
| */ |
| private final SimpleArrayMap<AnimationFrameCallback, Long> mDelayedCallbackStartTime = |
| new SimpleArrayMap<>(); |
| public static final ThreadLocal<AnimationHandler> sAnimatorHandler = new ThreadLocal<>(); |
| private final ArrayList<AnimationFrameCallback> mAnimationCallbacks = new ArrayList<>(); |
| private AnimationFrameCallbackProvider mProvider; |
| |
| private long mCurrentFrameTime = 0; |
| private final Choreographer.FrameCallback mFrameCallback = new Choreographer.FrameCallback() { |
| @Override |
| public void doFrame(long frameTimeNanos) { |
| mCurrentFrameTime = System.currentTimeMillis(); |
| doAnimationFrame(mCurrentFrameTime); |
| if (mAnimationCallbacks.size() > 0) { |
| getProvider().postFrameCallback(this); |
| } |
| } |
| }; |
| |
| private boolean mListDirty = false; |
| |
| public static AnimationHandler getInstance() { |
| if (sAnimatorHandler.get() == null) { |
| sAnimatorHandler.set(new AnimationHandler()); |
| } |
| return sAnimatorHandler.get(); |
| } |
| |
| public static long getFrameTime() { |
| if (sAnimatorHandler.get() == null) { |
| return 0; |
| } |
| return sAnimatorHandler.get().mCurrentFrameTime; |
| } |
| |
| /** |
| * By default, the Choreographer is used to provide timing for frame callbacks. A custom |
| * provider can be used here to provide different timing pulse. |
| */ |
| public void setProvider(AnimationFrameCallbackProvider provider) { |
| if (provider == null) { |
| mProvider = new MyFrameCallbackProvider(); |
| } else { |
| mProvider = provider; |
| } |
| } |
| |
| private AnimationFrameCallbackProvider getProvider() { |
| if (mProvider == null) { |
| mProvider = new MyFrameCallbackProvider(); |
| } |
| return mProvider; |
| } |
| |
| /** |
| * Register to get a callback on the next frame after the delay. |
| */ |
| public void addAnimationFrameCallback(final AnimationFrameCallback callback, long delay) { |
| if (mAnimationCallbacks.size() == 0) { |
| getProvider().postFrameCallback(mFrameCallback); |
| } |
| if (!mAnimationCallbacks.contains(callback)) { |
| mAnimationCallbacks.add(callback); |
| } |
| |
| if (delay > 0) { |
| mDelayedCallbackStartTime.put(callback, (SystemClock.uptimeMillis() + delay)); |
| } |
| } |
| /** |
| * Removes the given callback from the list, so it will no longer be called for frame related |
| * timing. |
| */ |
| public void removeCallback(AnimationFrameCallback callback) { |
| mDelayedCallbackStartTime.remove(callback); |
| int id = mAnimationCallbacks.indexOf(callback); |
| if (id >= 0) { |
| mAnimationCallbacks.set(id, null); |
| mListDirty = true; |
| } |
| } |
| |
| private void doAnimationFrame(long frameTime) { |
| long currentTime = SystemClock.uptimeMillis(); |
| for (int i = 0; i < mAnimationCallbacks.size(); i++) { |
| final AnimationFrameCallback callback = mAnimationCallbacks.get(i); |
| if (callback == null) { |
| continue; |
| } |
| if (isCallbackDue(callback, currentTime)) { |
| callback.doAnimationFrame(frameTime); |
| } |
| } |
| cleanUpList(); |
| } |
| |
| /** |
| * Remove the callbacks from mDelayedCallbackStartTime once they have passed the initial delay |
| * so that they can start getting frame callbacks. |
| * |
| * @return true if they have passed the initial delay or have no delay, false otherwise. |
| */ |
| private boolean isCallbackDue(AnimationFrameCallback callback, long currentTime) { |
| Long startTime = mDelayedCallbackStartTime.get(callback); |
| if (startTime == null) { |
| return true; |
| } |
| if (startTime < currentTime) { |
| mDelayedCallbackStartTime.remove(callback); |
| return true; |
| } |
| return false; |
| } |
| |
| private void cleanUpList() { |
| if (mListDirty) { |
| for (int i = mAnimationCallbacks.size() - 1; i >= 0; i--) { |
| if (mAnimationCallbacks.get(i) == null) { |
| mAnimationCallbacks.remove(i); |
| } |
| } |
| mListDirty = false; |
| } |
| } |
| |
| /** |
| * Default provider of timing pulse that uses Choreographer for frame callbacks. |
| */ |
| private static class MyFrameCallbackProvider implements AnimationFrameCallbackProvider { |
| |
| final Choreographer mChoreographer = Choreographer.getInstance(); |
| |
| @Override |
| public void postFrameCallback(Choreographer.FrameCallback callback) { |
| mChoreographer.postFrameCallback(callback); |
| } |
| } |
| |
| /** |
| * The intention for having this interface is to increase the testability of ValueAnimator. |
| * Specifically, we can have a custom implementation of the interface below and provide |
| * timing pulse without using Choreographer. That way we could use any arbitrary interval for |
| * our timing pulse in the tests. |
| * |
| * @hide |
| */ |
| public interface AnimationFrameCallbackProvider { |
| void postFrameCallback(Choreographer.FrameCallback callback); |
| } |
| } |