android framework车载桌面CarLauncher的TaskView详细源码分析

1、构建相关的TaskView，装载到对应的ViewGroup

b站免费视频教程讲解：
https://www.bilibili.com/video/BV1wj411o7A9/

//packages/apps/Car/Launcher/src/com/android/car/carlauncher/CarLauncher.java
void onCreate() {//ignoresetContentView(R.layout.car_launcher);// We don't want to show Map card unnecessarily for the headless user 0.if (!UserHelperLite.isHeadlessSystemUser(getUserId())) {ViewGroup mapsCard = findViewById(R.id.maps_card);if (mapsCard != null) {//这里获取了mapsCard后，接下来就是构造出对应的TaskViewsetUpTaskView(mapsCard);}}//ignore}//进行TaskView相关的设置private void setUpTaskView(ViewGroup parent) {//把TaskViewManager进行构造mTaskViewManager = new TaskViewManager(this,new HandlerExecutor(getMainThreadHandler()), mCarActivityManagerRef);//创建对应的TaskViewmTaskViewManager.createTaskView(taskView -> {taskView.setListener(getMainExecutor(), mTaskViewListener);//把TaskView添加到了mapsCardparent.addView(taskView);mTaskView = taskView;});}//packages/apps/Car/Launcher/src/com/android/car/carlauncher/TaskViewManager.javapublic TaskViewManager(@UiContext Context context, HandlerExecutor handlerExecutor,AtomicReference<CarActivityManager> carActivityManagerRef) {mContext = context;mExecutor = handlerExecutor;//构造对应的ShellTaskOrganizermTaskOrganizer = new ShellTaskOrganizer(mExecutor, mContext);//把TaskOrganizer进行对应的注册initTaskOrganizer(carActivityManagerRef, transactionPool);}//构造出TaskViewvoid createTaskView(Consumer<TaskView> onCreate) {CarTaskView taskView = new CarTaskView(mContext, mTaskOrganizer, mSyncQueue);mExecutor.execute(() -> {onCreate.accept(taskView);});}

总结：
1、构建出对应的TaskViewManager，主要是注册和初始化TaskOrganizer
2、创建出相关的TaskView即SurfaceView，并放置到CarLauncher的ViewGroup

时序图如下：

2、相关Activity的启动情况

启动Activity相关堆栈

07-26 17:25:48.075  1584  1584 I lsm3333 : TaskView startActivity
07-26 17:25:48.075  1584  1584 I lsm3333 : java.lang.Exception
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.wm.shell.TaskView.startActivity(TaskView.java:179)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.car.carlauncher.CarLauncher.startMapsInTaskView(CarLauncher.java:373)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.car.carlauncher.CarLauncher.-$$Nest$mstartMapsInTaskView(Unknown Source:0)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.car.carlauncher.CarLauncher$1.onInitialized(CarLauncher.java:108)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.wm.shell.TaskView.lambda$surfaceCreated$11$com-android-wm-shell-TaskView(TaskView.java:416)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.wm.shell.TaskView$$ExternalSyntheticLambda11.run(Unknown Source:2)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at android.os.Handler.handleCallback(Handler.java:942)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at android.os.Handler.dispatchMessage(Handler.java:99)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at android.os.Looper.loopOnce(Looper.java:201)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at android.os.Looper.loop(Looper.java:288)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at android.app.ActivityThread.main(ActivityThread.java:7898)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at java.lang.reflect.Method.invoke(Native Method)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
07-26 17:25:48.075  1584  1584 I lsm3333 :  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)

主要代码流程步骤如下：
TaskView.onInitialized -->CarLauncher.startMapsInTaskView -->
TaskView.startActivity -->TaskView.prepareActivityOptions -->PendingIntent.send
相关时序图如下：

3、Task启动后，进行相关的surface重新挂载操作

Task启动完成后进行相关的onTaskAppeared回调：
相关堆栈：

07-26 17:33:03.205  2931  2931 I lsm3333 : onTaskAppeared taskInfo = TaskInfo{userId=10 taskId=1000013 displayId=0 isRunning=true baseIntent=Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.android.car.mapsplaceholder/.MapsPlaceholderActivity } baseActivity=ComponentInfo{com.android.car.mapsplaceholder/com.android.car.mapsplaceholder.MapsPlaceholderActivity} topActivity=ComponentInfo{com.android.car.mapsplaceholder/com.android.car.mapsplaceholder.MapsPlaceholderActivity} origActivity=null realActivity=ComponentInfo{com.android.car.mapsplaceholder/com.android.car.mapsplaceholder.MapsPlaceholderActivity} numActivities=1 lastActiveTime=462943 supportsSplitScreenMultiWindow=false supportsMultiWindow=true resizeMode=2 isResizeable=true minWidth=-1 minHeight=-1 defaultMinSize=220 token=WCT{android.window.IWindowContainerToken$Stub$Proxy@8b9b010} topActivityType=1 pictureInPictureParams=null shouldDockBigOverlays=false launchIntoPipHostTaskId=0 displayCutoutSafeInsets=null topActivityInfo=ActivityInfo{7150709 com.android.car.mapsplaceholder.MapsPlaceholderActivity} launchCookies=[android.os.Binder@a4aa911] positionInParent=Point(303, 57) parentTaskId=-1 isFocused=true isVisible=false isSleeping=false topActivityInSizeCompat=false topActivityEligibleForLetterboxEducation= false locusId=null displayAreaFeatureId=1 cameraCompatControlState=hidden}
07-26 17:33:03.205  2931  2931 I lsm3333 : java.lang.Exception
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.wm.shell.TaskView.onTaskAppeared(TaskView.java:313)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.car.carlauncher.CarTaskView.onTaskAppeared(CarTaskView.java:46)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.wm.shell.ShellTaskOrganizer.onTaskAppeared(ShellTaskOrganizer.java:440)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.wm.shell.ShellTaskOrganizer.onTaskAppeared(ShellTaskOrganizer.java:429)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.window.TaskOrganizer$1.lambda$onTaskAppeared$4$android-window-TaskOrganizer$1(TaskOrganizer.java:306)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.window.TaskOrganizer$1$$ExternalSyntheticLambda6.run(Unknown Source:6)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.os.Handler.handleCallback(Handler.java:942)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.os.Handler.dispatchMessage(Handler.java:99)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.os.Looper.loopOnce(Looper.java:201)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.os.Looper.loop(Looper.java:288)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.app.ActivityThread.main(ActivityThread.java:7898)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at java.lang.reflect.Method.invoke(Native Method)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)

4、Task启动过程通知流程详细分析

1、首先要监听Task相关的显示情况，必须要注册相关的监听方法
进行相关的ShellTaskOrganizer构造

//省略相关方法
public TaskViewManager(@UiContext Context context, HandlerExecutor handlerExecutor,AtomicReference<CarActivityManager> carActivityManagerRef) {//构造对应的TaskOrganizermTaskOrganizer = new ShellTaskOrganizer(mExecutor, mContext);initTaskOrganizer(carActivityManagerRef, transactionPool);}private void initTaskOrganizer(AtomicReference<CarActivityManager> carActivityManagerRef,TransactionPool transactionPool) {//这个方法关键注册到systemserver端，建立联系List<TaskAppearedInfo> taskAppearedInfos = mTaskOrganizer.registerOrganizer();}public List<TaskAppearedInfo> registerOrganizer() {try {//这里就是正式的跨进程，把mInterface传递给systemserver方便回调return mTaskOrganizerController.registerTaskOrganizer(mInterface).getList();} catch (RemoteException e) {throw e.rethrowFromSystemServer();}}

总结：上面几步最重要就是与systemserver端建立了联系，而且把相关的回调的mInterface传递到了systemserver端，这样systemserver端就可以在Task有变化情况下通过mInterface通知到客户端

2、监听后怎么准确的通知到TaskView

上面第一步已经实现了CarLauncher可以监听Task的相关行为，注意这里肯定是所有的Task行为，但是TaskView它自身只关心Map相关的Task，那么这里是怎么精准通知的呢？

这里可以通过一个堆栈看看：

07-26 17:33:03.205  2931  2931 I lsm3333 :   at com.android.car.carlauncher.CarTaskView.onTaskAppeared(CarTaskView.java:46)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.wm.shell.ShellTaskOrganizer.onTaskAppeared(ShellTaskOrganizer.java:440)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at com.android.wm.shell.ShellTaskOrganizer.onTaskAppeared(ShellTaskOrganizer.java:429)
07-26 17:33:03.205  2931  2931 I lsm3333 :  at android.window.TaskOrganizer$1.lambda$onTaskAppeared$4$android-window-TaskOrganizer$1(TaskOrganizer.java:306)

可以明显看出这里systemserver跨进程回调到了ShellTaskOrganizer的onTaskAppeared，在这个方法进行精准匹配到TaskView关心的Task变化，然后进行通知

private void onTaskAppeared(TaskAppearedInfo info) {final int taskId = info.getTaskInfo().taskId;mTasks.put(taskId, info);//这里进行对应的TaskListener获取，这里就是TaskView的listener获取，本身TaskView是有实现 ShellTaskOrganizer.TaskListener接口的final TaskListener listener =getTaskListener(info.getTaskInfo(), true /*removeLaunchCookieIfNeeded*/);//获取了TaskView的Listener后就可以进行通知了，从而他知道TaskView的onTaskAppearedif (listener != null) {listener.onTaskAppeared(info.getTaskInfo(), info.getLeash());}}

接下来就是重点分析这个getTaskListener，是怎么可以准确知道当前通知的Task信息就是TaskView对应的Task信息


private TaskListener getTaskListener(RunningTaskInfo runningTaskInfo,boolean removeLaunchCookieIfNeeded) {//这里的launchCookies属于系统端回调带的final ArrayList<IBinder> launchCookies = runningTaskInfo.launchCookies;for (int i = launchCookies.size() - 1; i >= 0; --i) {final IBinder cookie = launchCookies.get(i);//拿系统端的回调的cookie与本地进行匹配，配上了就进行获取了相关的listenerlistener = mLaunchCookieToListener.get(cookie);if (removeLaunchCookieIfNeeded) {// Remove the cookie and add the listener.mLaunchCookieToListener.remove(cookie);mTaskListeners.put(taskId, listener);}return listener;}return mTaskListeners.get(taskListenerType);}

上面看出核心就是服务端会在TaskInfo中有对应的cookie，然后本地也有对应的cookie集合map，这样实现的准确匹配。
那么这个cookie来自哪里呢？哈哈，其实这个cookie都是来自客户端的，在启动activity时候就构造设置了

 public void startActivity(@NonNull PendingIntent pendingIntent, @Nullable Intent fillInIntent,@NonNull ActivityOptions options, @Nullable Rect launchBounds) {//在这prepareActivityOptions进行了相关参数的设置prepareActivityOptions(options, launchBounds);//省略}

来看看prepareActivityOptions方法：

 private void prepareActivityOptions(ActivityOptions options, Rect launchBounds) {//构造出了这个cookie，其实就是binder对象final Binder launchCookie = new Binder();mShellExecutor.execute(() -> {//这里把这个cookie进行相关的存放到mapmTaskOrganizer.setPendingLaunchCookieListener(launchCookie, this);});options.setLaunchBounds(launchBounds);//把cookie设置进了option，可以传递到systemserver端options.setLaunchCookie(launchCookie);options.setLaunchWindowingMode(WINDOWING_MODE_MULTI_WINDOW);options.setRemoveWithTaskOrganizer(true);}public void setPendingLaunchCookieListener(IBinder cookie, TaskListener listener) {synchronized (mLock) {//把这里的cookie放到了mLaunchCookieToListener的集合中mLaunchCookieToListener.put(cookie, listener);}}

通过这个cookie即可以精准的把系统回调的TaskInfo匹配到对应的TaskView