Android U 多任务启动分屏——整体流程介绍

序

原生的分屏功能是在多任务中，点击应用图标选择分屏，在选择多任务中的其他应用进行分屏

整体流程

层级结构

#1 DefaultTaskDisplayArea type=undefined mode=fullscreen override-mode=fullscreen requested-bounds=[0,0][0,0] bounds=[0,0][1440,2960]
 #1 Task=3 type=standard mode=fullscreen override-mode=fullscreen requested-bounds=[0,0][0,0] bounds=[0,0][1440,2960]
  #1 Task=4 type=standard mode=multi-window override-mode=multi-window requested-bounds=[0,1498][1440,2960] bounds=[0,1498][1440,2960]
   #0 Task=55 type=standard mode=multi-window override-mode=undefined requested-bounds=[0,0][0,0] bounds=[0,1498][1440,2960]
    #0 ActivityRecord{c8a85d8 u0 com.android.dialer/.main.impl.MainActivity t55} type=standard mode=multi-window override-mode=undefined requested-bounds=[0,0][0,0] bounds=[0,1498][1440,2960]
     #0 17b29c2 com.android.dialer/com.android.dialer.main.impl.MainActivity type=standard mode=multi-window override-mode=undefined requested-bounds=[0,0][0,0] bounds=[0,1498][1440,2960]
  #0 Task=5 type=standard mode=multi-window override-mode=multi-window requested-bounds=[0,0][1440,1463] bounds=[0,0][1440,1463]
   #0 Task=61 type=standard mode=multi-window override-mode=undefined requested-bounds=[0,0][0,0] bounds=[0,0][1440,1463]
    #0 ActivityRecord{a029103 u0 com.android.messaging/.ui.conversationlist.ConversationListActivity t61} type=standard mode=multi-window override-mode=undefined requested-bounds=[0,0][0,0] bounds=[0,0][1440,1463]
     #0 d3dd038 com.android.messaging/com.android.messaging.ui.conversationlist.ConversationListActivity type=standard mode=multi-window override-mode=undefined requested-bounds=[0,0][0,0] bounds=[0,0][1440,1463]

对应如下树状图

各模块责任与堆栈

Launcher

1.确定分屏上部分，做好相关显示动画，等待选择下分屏

Launcher: 	at com.android.quickstep.views.RecentsView.createInitialSplitSelectAnimation(RecentsView.java:3196)
Launcher: 	at com.android.quickstep.views.RecentsView.createTaskDismissAnimation(RecentsView.java:3493)
Launcher: 	at com.android.quickstep.views.RecentsView.createSplitSelectInitAnimation(RecentsView.java:4636)
Launcher: 	at com.android.launcher3.uioverrides.RecentsViewStateController.handleSplitSelectionState(RecentsViewStateController.java:139)
Launcher: 	at com.android.launcher3.uioverrides.RecentsViewStateController.setStateWithAnimationInternal(RecentsViewStateController.java:109)
Launcher: 	at com.android.launcher3.uioverrides.BaseRecentsViewStateController.setStateWithAnimation(BaseRecentsViewStateController.java:91)
Launcher: 	at com.android.launcher3.uioverrides.BaseRecentsViewStateController.setStateWithAnimation(BaseRecentsViewStateController.java:61)
Launcher: 	at com.android.launcher3.statemanager.StateManager.createAnimationToNewWorkspaceInternal(StateManager.java:350)
Launcher: 	at com.android.launcher3.statemanager.StateManager.goToStateAnimated(StateManager.java:285)
Launcher: 	at com.android.launcher3.statemanager.StateManager.goToState(StateManager.java:273)
Launcher: 	at com.android.launcher3.statemanager.StateManager.goToState(StateManager.java:152)
Launcher: 	at com.android.launcher3.statemanager.StateManager.goToState(StateManager.java:145)
Launcher: 	at com.android.quickstep.views.LauncherRecentsView.initiateSplitSelect(LauncherRecentsView.java:210)
Launcher: 	at com.android.quickstep.views.TaskView.initiateSplitSelect(TaskView.java:1767)
Launcher: 	at com.android.quickstep.TaskShortcutFactory$SplitSelectSystemShortcut.onClick(TaskShortcutFactory.java:124)
Launcher: 	at com.android.quickstep.views.TaskMenuView$$ExternalSyntheticLambda3.onClick(Unknown Source:2)
Launcher: 	at android.view.View.performClick(View.java:7659)
Launcher: 	at android.view.View.performClickInternal(View.java:7636)
Launcher: 	at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0)
Launcher: 	at android.view.View$PerformClick.run(View.java:30156)
Launcher: 	at android.os.Handler.handleCallback(Handler.java:958)
Launcher: 	at android.os.Handler.dispatchMessage(Handler.java:99)
Launcher: 	at android.os.Looper.loopOnce(Looper.java:205)
Launcher: 	at android.os.Looper.loop(Looper.java:294)
Launcher: 	at android.app.ActivityThread.main(ActivityThread.java:8177)
Launcher: 	at java.lang.reflect.Method.invoke(Native Method)
Launcher: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
Launcher: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

2.确定选择下分屏，播放相关动画，调用SytemUI接口进入到真正分屏

Launcher: 	at com.android.quickstep.views.RecentsView.confirmSplitSelect(RecentsView.java:4716)
Launcher: 	at com.android.quickstep.views.TaskView.confirmSecondSplitSelectApp(TaskView.java:762)
Launcher: 	at com.android.quickstep.views.TaskView.onClick(TaskView.java:746)
Launcher: 	at com.android.quickstep.views.TaskView.$r8$lambda$2dErZAYzRAWboZR0vn31kIz_HGY(Unknown Source:0)
Launcher: 	at com.android.quickstep.views.TaskView$$ExternalSyntheticLambda2.onClick(Unknown Source:2)
Launcher: 	at android.view.View.performClick(View.java:7659)
Launcher: 	at android.view.View.performClickInternal(View.java:7636)
Launcher: 	at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0)
Launcher: 	at android.view.View$PerformClick.run(View.java:30156)
Launcher: 	at android.os.Handler.handleCallback(Handler.java:958)
Launcher: 	at android.os.Handler.dispatchMessage(Handler.java:99)
Launcher: 	at android.os.Looper.loopOnce(Looper.java:205)
Launcher: 	at android.os.Looper.loop(Looper.java:294)
Launcher: 	at android.app.ActivityThread.main(ActivityThread.java:8177)
Launcher: 	at java.lang.reflect.Method.invoke(Native Method)
Launcher: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
Launcher: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

pendingAnimation.addEndListener(aBoolean -> {
            mSplitSelectStateController.launchSplitTasks(
                    aBoolean1 -> RecentsView.this.resetFromSplitSelectionState());
            InteractionJankMonitorWrapper.end(InteractionJankMonitorWrapper.CUJ_SPLIT_SCREEN_ENTER);
        });

Launcher: 	at com.android.quickstep.util.SplitSelectStateController.launchTasksRefactored(SplitSelectStateController.java:412)
Launcher: 	at com.android.quickstep.util.SplitSelectStateController.launchTasks(SplitSelectStateController.java:329)
Launcher: 	at com.android.quickstep.util.SplitSelectStateController.launchSplitTasks(SplitSelectStateController.java:258)
Launcher: 	at com.android.quickstep.views.RecentsView.lambda$confirmSplitSelect$34(RecentsView.java:4718)
Launcher: 	at com.android.quickstep.views.RecentsView.$r8$lambda$uSHMT-0i9azkpL6YW9McOOFyjVQ(Unknown Source:0)
Launcher: 	at com.android.quickstep.views.RecentsView$$ExternalSyntheticLambda26.accept(Unknown Source:4)
Launcher: 	at com.android.launcher3.anim.AnimatorListeners$EndStateCallbackWrapper.onAnimationEnd(AnimatorListeners.java:80)
Launcher: 	at android.animation.Animator$AnimatorListener.onAnimationEnd(Animator.java:711)
Launcher: 	at android.animation.Animator$AnimatorCaller$$ExternalSyntheticLambda1.call(Unknown Source:4)
Launcher: 	at android.animation.Animator.callOnList(Animator.java:669)
Launcher: 	at android.animation.Animator.notifyListeners(Animator.java:608)
Launcher: 	at android.animation.Animator.notifyEndListeners(Animator.java:633)
Launcher: 	at android.animation.ValueAnimator.endAnimation(ValueAnimator.java:1306)
Launcher: 	at android.animation.ValueAnimator.doAnimationFrame(ValueAnimator.java:1566)
Launcher: 	at android.animation.ValueAnimator.pulseAnimationFrame(ValueAnimator.java:1582)
Launcher: 	at android.animation.AnimatorSet.pulseFrame(AnimatorSet.java:1314)
Launcher: 	at android.animation.AnimatorSet.handleAnimationEvents(AnimatorSet.java:1297)
Launcher: 	at android.animation.AnimatorSet.doAnimationFrame(AnimatorSet.java:1197)
Launcher: 	at android.animation.AnimationHandler.doAnimationFrame(AnimationHandler.java:328)
Launcher: 	at android.animation.AnimationHandler.-$$Nest$mdoAnimationFrame(Unknown Source:0)
Launcher: 	at android.animation.AnimationHandler$1.doFrame(AnimationHandler.java:86)
Launcher: 	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1337)
Launcher: 	at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1348)
Launcher: 	at android.view.Choreographer.doCallbacks(Choreographer.java:952)
Launcher: 	at android.view.Choreographer.doFrame(Choreographer.java:878)
Launcher: 	at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1322)
Launcher: 	at android.os.Handler.handleCallback(Handler.java:958)
Launcher: 	at android.os.Handler.dispatchMessage(Handler.java:99)
Launcher: 	at android.os.Looper.loopOnce(Looper.java:205)
Launcher: 	at android.os.Looper.loop(Looper.java:294)
Launcher: 	at android.app.ActivityThread.main(ActivityThread.java:8177)
Launcher: 	at java.lang.reflect.Method.invoke(Native Method)
Launcher: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
Launcher: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

SystemUiProxy调用ISplitScreen.aidl进行跨进程通信到SystemUI进程

SytemUI

SplitScreenController实现了ISplitScreen.aidl

SplitScreen: 	at android.window.WindowOrganizer.startNewTransition(WindowOrganizer.java:94)
SplitScreen: 	at com.android.wm.shell.transition.Transitions.startTransition(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:1121)
SplitScreen: 	at com.android.wm.shell.splitscreen.SplitScreenTransitions.startEnterTransition(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:345)
SplitScreen: 	at com.android.wm.shell.splitscreen.StageCoordinator.startWithTask(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:701)
SplitScreen: 	at com.android.wm.shell.splitscreen.StageCoordinator.startTasks(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:623)
SplitScreen: 	at com.android.wm.shell.splitscreen.SplitScreenController$ISplitScreenImpl.lambda$startTasks$11(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:1157)
SplitScreen: 	at com.android.wm.shell.splitscreen.SplitScreenController$ISplitScreenImpl.$r8$lambda$UuHBVv3bzz4CDOdyAqlv4kaRHgY(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:0)
SplitScreen: 	at com.android.wm.shell.splitscreen.SplitScreenController$ISplitScreenImpl$$ExternalSyntheticLambda14.accept(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:0)
SplitScreen: 	at com.android.wm.shell.common.ExecutorUtils.lambda$executeRemoteCallWithTaskPermission$1(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:60)
SplitScreen: 	at com.android.wm.shell.common.ExecutorUtils.$r8$lambda$s8eUOdyrqpqzzyFwAMGxO-MaCg4(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:0)
SplitScreen: 	at com.android.wm.shell.common.ExecutorUtils$$ExternalSyntheticLambda1.run(go/retraceme d8ee0e3eecdad3cdc77c111ff5591ebe26372c47d62ba59187c5ecf96366b561:0)
SplitScreen: 	at android.os.Handler.handleCallback(Handler.java:958)
SplitScreen: 	at android.os.Handler.dispatchMessage(Handler.java:99)
SplitScreen: 	at android.os.Looper.loopOnce(Looper.java:205)
SplitScreen: 	at android.os.Looper.loop(Looper.java:294)
SplitScreen: 	at android.os.HandlerThread.run(HandlerThread.java:67)

1.对上分屏的Task进行启动

2.设置好对应的bound到configration中

3.对分屏的RootTask进行排位到最顶部

4.对下分屏的Task进行启动

对Task的操作均会保存到WindowContainerTransaction对象中，最后通过WindowOrganizer调用IWindowOrganizerController.aidl进行跨进程通信到SystemServer进程进程Task操作

注：SplitLayout初始化分屏的分割线的布局的流程，从代码上看，如果shell动画开关是打开的，那么该流程在1和2之间执行；反之，则会在4之后，即窗口relayout流程中通过shell动画流程调用。

SystemServer

WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.applyTransaction(WindowOrganizerController.java:597)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.applyTransaction(WindowOrganizerController.java:484)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.applyTransaction(WindowOrganizerController.java:502)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.lambda$startTransition$3(WindowOrganizerController.java:314)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.$r8$lambda$v_6sOG-rerjgO2wQxXrUcgpnWaU(WindowOrganizerController.java:0)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController$$ExternalSyntheticLambda3.onCollectStarted(R8$$SyntheticClass:0)
WindowOrganizerController: 	at com.android.server.wm.TransitionController.startCollectOrQueue(TransitionController.java:1306)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.startTransition(WindowOrganizerController.java:310)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.startNewTransition(WindowOrganizerController.java:271)
WindowOrganizerController: 	at android.window.IWindowOrganizerController$Stub.onTransact(IWindowOrganizerController.java:245)
WindowOrganizerController: 	at com.android.server.wm.WindowOrganizerController.onTransact(WindowOrganizerController.java:188)
WindowOrganizerController: 	at android.os.Binder.execTransactInternal(Binder.java:1344)
WindowOrganizerController: 	at android.os.Binder.execTransact(Binder.java:1275)

WindowOrganizerController实现了IWindowOrganizerController.aidl
其接收SystemUI中的命令来对Task进行不同的操作
applyTransaction中对Task区域大小bounds变化以及RootTask的reorder和startTask等操作进行了处理

交互简图