Android11 窗口动画

作者：神奇cpp | 2024-07-11 00:03:47

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Android11 窗口动画

窗口进入动画
应用端窗口绘制完成之后，调用finshDraw告知WMS，WMS这边最后就会调用WindowSurfacePlacer的performSurfacePlacement方法，最终调用到 WindowStateAnimator的commitFinishDrawingLocked方法

//frameworks/base/services/core/java/com/android/server/wm/WindowStateAnimator.java
	boolean commitFinishDrawingLocked() {
       
       //省略
        mDrawState = READY_TO_SHOW;//READY_TO_SHOW状态
        boolean result = false;
        final ActivityRecord activity = mWin.mActivityRecord;
        if (activity == null || activity.canShowWindows()
                || mWin.mAttrs.type == TYPE_APPLICATION_STARTING) {
            result = mWin.performShowLocked();
        }
        return result;
    }
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对于系统窗口，直接调用WindowState的performShowLocked 方法

//frameworks/base/services/core/java/com/android/server/wm/WindowState.java
boolean performShowLocked() {
	//省略
	mWinAnimator.applyEnterAnimationLocked();//动画
	mWinAnimator.mDrawState = HAS_DRAWN;//HAS_DRAWN状态
	//省略
}
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applyEnterAnimationLocked

//frameworks/base/services/core/java/com/android/server/wm/WindowStateAnimator.java
void applyEnterAnimationLocked() {
      	//省略
        final int transit;
        if (mEnterAnimationPending) {
            mEnterAnimationPending = false;
            transit = WindowManagerPolicy.TRANSIT_ENTER;//走这个分支
        } else {
            transit = WindowManagerPolicy.TRANSIT_SHOW;
        }

        // We don't apply animation for application main window here since this window type
        // should be controlled by AppWindowToken in general.
        if (mAttrType != TYPE_BASE_APPLICATION) {
            applyAnimationLocked(transit, true);//动画
        }
	//省略
    }
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最后调用applyAnimationLocked去播放动画。

窗口退出动画
应用端remove，导致WMS的removeWindow被调用

//frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java
 void removeWindow(Session session, IWindow client) {
        synchronized (mGlobalLock) {
            WindowState win = windowForClientLocked(session, client, false);
            if (win != null) {
                win.removeIfPossible();
                return;
            }

            // Remove embedded window map if the token belongs to an embedded window
            mEmbeddedWindowController.remove(client);
        }
    }
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removeIfPossible

//frameworks/base/services/core/java/com/android/server/wm/WindowState.java
@Override
    void removeIfPossible() {
        super.removeIfPossible();
        removeIfPossible(false /*keepVisibleDeadWindow*/);
        immediatelyNotifyBlastSync();
    }

private void removeIfPossible(boolean keepVisibleDeadWindow) {
	//省略
if (wasVisible) {
	final int transit = (!startingWindow) ? TRANSIT_EXIT : TRANSIT_PREVIEW_DONE;//transit 为TRANSIT_EXIT 

	// Try starting an animation.
	if (mWinAnimator.applyAnimationLocked(transit, false)) {
		mAnimatingExit = true;
		//省略
	}
}
//省略
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和窗口进入动画一样，也是调用WindowStateAnimator的applyAnimationLocked去处理动画相关的工作,只是传入的参数不一致。窗口进入时，transit为TRANSIT_ENTER，退出时，transit为TRANSIT_EXIT

applyAnimationLocked

//frameworks/base/services/core/java/com/android/server/wm/WindowStateAnimator.java
boolean applyAnimationLocked(int transit, boolean isEntrance) {
	//省略
	if (mWin.mToken.okToAnimate()) {
		int anim = mWin.getDisplayContent().getDisplayPolicy().selectAnimation(mWin, transit);//对于系统窗口，返回0
		Animation a = null;
		if (anim != DisplayPolicy.ANIMATION_STYLEABLE) {
           //省略    
    	} else {//进这个分支
			switch (transit) {
                    case WindowManagerPolicy.TRANSIT_ENTER:
                        attr = com.android.internal.R.styleable.WindowAnimation_windowEnterAnimation;
                        break;
                    case WindowManagerPolicy.TRANSIT_EXIT:
                        attr = com.android.internal.R.styleable.WindowAnimation_windowExitAnimation;
                        break;
                    case WindowManagerPolicy.TRANSIT_SHOW:
                        attr = com.android.internal.R.styleable.WindowAnimation_windowShowAnimation;
                        break;
                    case WindowManagerPolicy.TRANSIT_HIDE:
                        attr = com.android.internal.R.styleable.WindowAnimation_windowHideAnimation;
                        break;
                }
                if (attr >= 0) {
                    a = mWin.getDisplayContent().mAppTransition.loadAnimationAttr(
                            mWin.mAttrs, attr, TRANSIT_NONE);//加载动画
                }
		}
		if (a != null) {
                if (DEBUG_ANIM) logWithStack(TAG, "Loaded animation " + a + " for " + this);
                Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "WSA#startAnimation");
                mWin.startAnimation(a);//开始动画
                Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);
                mAnimationIsEntrance = isEntrance;
		}
		//省略
}
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首先根据不同的transit去加载不同的XML文件并创建对应的Animation 对象，然后调用WindowState的startAnimation 开始动画

//frameworks/base/services/core/java/com/android/server/wm/WindowState.java
void startAnimation(Animation anim) {
		//省略

        final DisplayInfo displayInfo = getDisplayInfo();
        anim.initialize(mWindowFrames.mFrame.width(), mWindowFrames.mFrame.height(),
                displayInfo.appWidth, displayInfo.appHeight);
        anim.restrictDuration(MAX_ANIMATION_DURATION);
        anim.scaleCurrentDuration(mWmService.getWindowAnimationScaleLocked());
        final AnimationAdapter adapter = new LocalAnimationAdapter(
                new WindowAnimationSpec(anim, mSurfacePosition, false /* canSkipFirstFrame */,
                        0 /* windowCornerRadius */),
                mWmService.mSurfaceAnimationRunner);//创建LocalAnimationAdapter
        startAnimation(getPendingTransaction(), adapter);
        commitPendingTransaction();
    }
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首先创建LocalAnimationAdapter对象，LocalAnimationAdapter对象中的mSpec成员是WindowAnimationSpec对象，WindowAnimationSpec对象中的mAnimation成员是上一步创建的Animation 对象。LocalAnimationAdapter对象中的mAnimator指向的是WMS中的mSurfaceAnimationRunner。创建好LocalAnimationAdapter对象后，继续调用startAnimation处理

//frameworks/base/services/core/java/com/android/server/wm/WindowState.java
 private void startAnimation(Transaction t, AnimationAdapter adapter) {
        startAnimation(t, adapter, mWinAnimator.mLastHidden, ANIMATION_TYPE_WINDOW_ANIMATION);
 }
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调用父类WindowContainer的startAnimation方法

//frameworks/base/services/core/java/com/android/server/wm/WindowContainer.java
void startAnimation(Transaction t, AnimationAdapter anim, boolean hidden,
            @AnimationType int type,
            @Nullable OnAnimationFinishedCallback animationFinishedCallback) {
            
        // TODO: This should use isVisible() but because isVisible has a really weird meaning at
        // the moment this doesn't work for all animatable window containers.
        mSurfaceAnimator.startAnimation(t, anim, hidden, type, animationFinishedCallback,
                mSurfaceFreezer);
    }

    void startAnimation(Transaction t, AnimationAdapter anim, boolean hidden,
            @AnimationType int type) {
        startAnimation(t, anim, hidden, type, null /* animationFinishedCallback */);
    }
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SurfaceAnimator.startAnimation

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimator.java
void startAnimation(Transaction t, AnimationAdapter anim, boolean hidden,
            @AnimationType int type,
            @Nullable OnAnimationFinishedCallback animationFinishedCallback,
            @Nullable SurfaceFreezer freezer) {
        cancelAnimation(t, true /* restarting */, true /* forwardCancel */);
        mAnimation = anim;//mAnimation 就为之前创建的LocalAnimationAdapter对象
        mAnimationType = type;
        mAnimationFinishedCallback = animationFinishedCallback;
        final SurfaceControl surface = mAnimatable.getSurfaceControl();//mAnimatable为窗口的WindowState
        mLeash = freezer != null ? freezer.takeLeashForAnimation() : null;
        if (mLeash == null) {
            mLeash = createAnimationLeash(mAnimatable, surface, t, type,
                    mAnimatable.getSurfaceWidth(), mAnimatable.getSurfaceHeight(), 0 /* x */,
                    0 /* y */, hidden, mService.mTransactionFactory);//创建leash图层
            mAnimatable.onAnimationLeashCreated(t, mLeash);
        }
        mAnimatable.onLeashAnimationStarting(t, mLeash);
      
        mAnimation.startAnimation(mLeash, t, type, mInnerAnimationFinishedCallback);//继续处理
    }
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首先创建leash图层，然后调用LocalAnimationAdapter的startAnimation继续处理，注意传入的mInnerAnimationFinishedCallback参数，后续动画完成后会回调里面的方法。高版本的动画都是基于leash图层来做的

createAnimationLeash

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimator.java
static SurfaceControl createAnimationLeash(Animatable animatable, SurfaceControl surface,
            Transaction t, @AnimationType int type, int width, int height, int x, int y,
            boolean hidden, Supplier<Transaction> transactionFactory) {
        if (DEBUG_ANIM) Slog.i(TAG, "Reparenting to leash");
        final SurfaceControl.Builder builder = animatable.makeAnimationLeash()
                .setParent(animatable.getAnimationLeashParent())//将leash图层挂载到WindowState父亲的图层下
                .setName(surface + " - animation-leash")
                // TODO(b/151665759) Defer reparent calls
                // We want the leash to be visible immediately because the transaction which shows
                // the leash may be deferred but the reparent will not. This will cause the leashed
                // surface to be invisible until the deferred transaction is applied. If this
                // doesn't work, you will can see the 2/3 button nav bar flicker during seamless
                // rotation.
                .setHidden(hidden)
                .setEffectLayer()
                .setCallsite("SurfaceAnimator.createAnimationLeash");
        final SurfaceControl leash = builder.build();
        t.setWindowCrop(leash, width, height);
        t.setPosition(leash, x, y);
        t.show(leash);
        t.setAlpha(leash, hidden ? 0 : 1);

        t.reparent(surface, leash);//将windowState的图层挂载在leash下
        return leash;
    }
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注意这这只是对surface图层的关系进行操作，WMS这边的层级树是没有改变的。此时，图层的关系如下：
在这里插入图片描述
LocalAnimationAdapter.startAnimation

//frameworks/base/services/core/java/com/android/server/wm/LocalAnimationAdapter.java
	@Override
    public void startAnimation(SurfaceControl animationLeash, Transaction t,
            @AnimationType int type, OnAnimationFinishedCallback finishCallback) {
        mAnimator.startAnimation(mSpec, animationLeash, t,
                () -> finishCallback.onAnimationFinished(type, this));//前面说过，mAnimator为SurfaceAnimationRunner对象,mSpec为WindowAnimationSpec对象
    }
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SurfaceAnimationRunner.startAnimation

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
void startAnimation(AnimationSpec a, SurfaceControl animationLeash, Transaction t,
            Runnable finishCallback) {
        synchronized (mLock) {
            final RunningAnimation runningAnim = new RunningAnimation(a, animationLeash,
                    finishCallback);//创建RunningAnimation对象
            mPendingAnimations.put(animationLeash, runningAnim);//放入map中，注意map中也放入了leash图层
            if (!mAnimationStartDeferred) {
                mChoreographer.postFrameCallback(this::startAnimations);//请求vsync
            }
			//省略
        }
    }
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又创建了一个RunningAnimation对象，RunningAnimation中的mAnimSpec为WindowAnimationSpec对象，这个WindowAnimationSpec对象中是有之前创建的Animation 对象的。然后将RunningAnimation对象保存到mPendingAnimations Map中。然后请求vsync信号。当vsync信号来了的时候，调用startAnimations方法

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
private void startAnimations(long frameTimeNanos) {
        synchronized (mLock) {
            startPendingAnimationsLocked();
        }
        mPowerManagerInternal.powerHint(PowerHint.INTERACTION, 0);
}

@GuardedBy("mLock")
    private void startPendingAnimationsLocked() {
        for (int i = mPendingAnimations.size() - 1; i >= 0; i--) {//遍历mPendingAnimations
            startAnimationLocked(mPendingAnimations.valueAt(i));
        }
        mPendingAnimations.clear();
    }

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startAnimationLocked就是去执行动画的播放了。

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
@GuardedBy("mLock")
    private void startAnimationLocked(RunningAnimation a) {
        final ValueAnimator anim = mAnimatorFactory.makeAnimator();//创建ValueAnimator 

        // Animation length is already expected to be scaled.
        anim.overrideDurationScale(1.0f);
        anim.setDuration(a.mAnimSpec.getDuration());
        anim.addUpdateListener(animation -> {
            synchronized (mCancelLock) {
                if (!a.mCancelled) {
                    final long duration = anim.getDuration();
                    long currentPlayTime = anim.getCurrentPlayTime();
                    if (currentPlayTime > duration) {
                        currentPlayTime = duration;
                    }
                    applyTransformation(a, mFrameTransaction, currentPlayTime);//播放动画
                }
            }

            // Transaction will be applied in the commit phase.
            scheduleApplyTransaction();//请求下一个vsync信号
        });
	
	//省略

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applyTransformation

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimationRunner.java
private void applyTransformation(RunningAnimation a, Transaction t, long currentPlayTime) {
        a.mAnimSpec.apply(t, a.mLeash, currentPlayTime);
    }
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WindowAnimationSpec.apply

//frameworks/base/services/core/java/com/android/server/wm/WindowAnimationSpec.java
@Override
    public void apply(Transaction t, SurfaceControl leash, long currentPlayTime) {
        final TmpValues tmp = mThreadLocalTmps.get();
        tmp.transformation.clear();
        mAnimation.getTransformation(currentPlayTime, tmp.transformation);
        tmp.transformation.getMatrix().postTranslate(mPosition.x, mPosition.y);
        t.setMatrix(leash, tmp.transformation.getMatrix(), tmp.floats);
        t.setAlpha(leash, tmp.transformation.getAlpha());

        boolean cropSet = false;
        if (mStackClipMode == STACK_CLIP_NONE) {
            if (tmp.transformation.hasClipRect()) {
                t.setWindowCrop(leash, tmp.transformation.getClipRect());
                cropSet = true;
            }
        } else {
            mTmpRect.set(mStackBounds);
            if (tmp.transformation.hasClipRect()) {
                mTmpRect.intersect(tmp.transformation.getClipRect());
            }
            t.setWindowCrop(leash, mTmpRect);
            cropSet = true;
        }

        // We can only apply rounded corner if a crop is set, as otherwise the value is meaningless,
        // since it doesn't have anything it's relative to.
        if (cropSet && mAnimation.hasRoundedCorners() && mWindowCornerRadius > 0) {
            t.setCornerRadius(leash, mWindowCornerRadius);
        }
    }
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可以看出播放动画就是对leash图层进行操作。

以一张图来总结下窗口动画的播放流程
在这里插入图片描述
leash图层的移除
在播放动画时，创建了leash图层，动画结束后需要移除该图层。
在上面SurfaceAnimationRunner的startAnimationLocked方法中，除了有动画更新的回调，当动画结束时也是有回调的

private void startAnimationLocked(RunningAnimation a) {
	//省略
	anim.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationStart(Animator animation) {
                synchronized (mCancelLock) {
                    if (!a.mCancelled) {
                        // TODO: change this back to use show instead of alpha when b/138459974 is
                        // fixed.
                        mFrameTransaction.setAlpha(a.mLeash, 1);
                    }
                }
            }

            @Override
            public void onAnimationEnd(Animator animation) {//动画结束
                synchronized (mLock) {
                    mRunningAnimations.remove(a.mLeash);
                    synchronized (mCancelLock) {
                        if (!a.mCancelled) {

                            // Post on other thread that we can push final state without jank.
                            mAnimationThreadHandler.post(a.mFinishCallback);
                        }
                    }
                }
            }
        });
	//省略
}
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动画结束时，post了一个Runnable，了解了前面动画的播放流程的话，就知道这个Runnable是 SurfaceAnimator的 mInnerAnimationFinishedCallback，mInnerAnimationFinishedCallback的定义如下

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimator.java
SurfaceAnimator(Animatable animatable,
            @Nullable OnAnimationFinishedCallback staticAnimationFinishedCallback,
            WindowManagerService service) {
       //省略
        mInnerAnimationFinishedCallback = getFinishedCallback(staticAnimationFinishedCallback);
}

private OnAnimationFinishedCallback getFinishedCallback(
            @Nullable OnAnimationFinishedCallback staticAnimationFinishedCallback) {
        return (type, anim) -> {
            synchronized (mService.mGlobalLock) {
                final SurfaceAnimator target = mService.mAnimationTransferMap.remove(anim);
                if (target != null) {
                    target.mInnerAnimationFinishedCallback.onAnimationFinished(type, anim);
                    return;
                }

                if (anim != mAnimation) {
                    return;
                }
                final Runnable resetAndInvokeFinish = () -> {
                    // We need to check again if the animation has been replaced with a new
                    // animation because the animatable may defer to finish.
                    if (anim != mAnimation) {
                        return;
                    }
                    final OnAnimationFinishedCallback animationFinishCallback =
                            mAnimationFinishedCallback;
                    reset(mAnimatable.getPendingTransaction(), true /* destroyLeash */);//移除leash
                   //省略
                };
                // If both the Animatable and AnimationAdapter requests to be deferred, only the
                // first one will be called.
                if (!(mAnimatable.shouldDeferAnimationFinish(resetAndInvokeFinish)
                        || anim.shouldDeferAnimationFinish(resetAndInvokeFinish))) {
                    resetAndInvokeFinish.run();//执行上面的Runnable 
                }
            }
        };
    }
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可以看出，动画结束时，调用reset去移除leash图层

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimator.java
private void reset(Transaction t, boolean destroyLeash) {
        mService.mAnimationTransferMap.remove(mAnimation);
        mAnimation = null;
        mAnimationFinishedCallback = null;
        mAnimationType = ANIMATION_TYPE_NONE;
        if (mLeash == null) {
            return;
        }
        SurfaceControl leash = mLeash;
        mLeash = null;
        final boolean scheduleAnim = removeLeash(t, mAnimatable, leash, destroyLeash);
        if (scheduleAnim) {
            mService.scheduleAnimationLocked();
        }
    }
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removeLeash

//frameworks/base/services/core/java/com/android/server/wm/SurfaceAnimator.java
static boolean removeLeash(Transaction t, Animatable animatable, @NonNull SurfaceControl leash,
            boolean destroy) {
        boolean scheduleAnim = false;
        final SurfaceControl surface = animatable.getSurfaceControl();//得到windowstate的图层
        final SurfaceControl parent = animatable.getParentSurfaceControl();//windowstate对应父节点的图层

        // If the surface was destroyed or the leash is invalid, we don't care to reparent it back.
        // Note that we also set this variable to true even if the parent isn't valid anymore, in
        // order to ensure onAnimationLeashLost still gets called in this case.
        final boolean reparent = surface != null;
        if (reparent) {
            if (DEBUG_ANIM) Slog.i(TAG, "Reparenting to original parent: " + parent);
            // We shouldn't really need these isValid checks but we do
            // b/130364451
            if (surface.isValid() && parent != null && parent.isValid()) {
                t.reparent(surface, parent);//将windowstate的图层重新挂载到父节点的图层下
                scheduleAnim = true;
            }
        }
        if (destroy) {
            t.remove(leash);//移除leash图层
            scheduleAnim = true;
        }

        if (reparent) {
            // Make sure to inform the animatable after the surface was reparented (or reparent
            // wasn't possible, but we still need to invoke the callback)
            animatable.onAnimationLeashLost(t);
            scheduleAnim = true;
        }
        return scheduleAnim;
    }
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所以，在动画播放和结束的流程中，图层有以下变化
在这里插入图片描述

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