启动流程的更改阅读

API 26

Launcher->AMS

AMS->ApplicationThread

AppLicationThread->Activity

--------------------------------Launcher-----------------------------------

Launcher#startActivity--->Activty#startActivityForResult(三个参数) --> Activity#Instrumentation#execStartActivity

-->Instrumentation#startActivity

---> IActivityManager#startActivity

--->AMS(ActivityManagerService)#mActivityStarter#startActivityMayWait

--------------------------------AMS------------------------------------

-->ActivityStarter#startActivityLocked-->ActivityStarter#startActivity-->ActivityStarter#startActivity-->ActivityStarter#startActivityUnchecked--> ActivityStarter#mSupervisor# resumeFocusedStackTopActivityLocked

---> ActiviltyStack#resumeTopActivityUncheckedLocked--> ActiviltyStack#resumeTopActivityInnerLocked--> ActiviltyStack#mStackSupervisor# startSpecificActivityLocked

---> ActivityStackSupervisor#realStartActivityLocked-->ActivityStackSupervisor#app.thread.scheduleLaunchActivity

--> ApplicationThread
--------------------------------ApplicationThread------------------------

ApplicationThread#scheduleLaunchActivity-->ApplicationThread#sendMessage

--->ActivityThread#handlerMessage

--->H#handleLaunchActivity

--->ActivityThread#performLaunchActivity--> ActivityThread#callActivityOrCreate

--->Instrumentation#PerformCreate

--->Activity#onCreate

API26-----API28-------以上
ActivityThread 的兼容变化

API23---API26----API28----以上

Instrumentation/ActivityManger/ActivityMangerNative 发生很大的变化，兼容难度增加

API 28 启动流程发生的变化

ActivityStackSupervisor#realStartActivityLocked --> ActivityStackSupervisor#mService.getLifecycleManager().scheduleTransaction

---> ClientLifecycleManager#schedule

---> ClientTransaction#scheduleTransaction (IApplicationThread mClient)

---> ActivityThread#ApplicationThread#scheduleTransaction  

(实际上是ActivityThread 内部创建，这里容易找不到)
  final ApplicationThread mAppThread = new ApplicationThread();
ActivityThread extends ClientTransactionHandler

---> ActivityThread extends ClientTransactionHandler#scheduleTransaction

---> ClientTransactionHandler#sendMessage ActivityThread.H.EXECUTE_TRANSACTION 159

---> H#handleMessage

---> TransactionExecutor#execute --> TransactionExecutor#executeCallbacks -->TransactionExecutor#List<ClientTransactionItem> #execute

这里面我们只能知道callback 得到的ClientTransactionItem ，一脸懵逼
我们看get，那么一定有add 方法。是谁加进来的。

回到入口看这句话

 // Schedule transaction.
                mService.getLifecycleManager().scheduleTransaction(clientTransaction);
继续向上翻
找到了addCallback，里面的LaunchActivityItem -----------想骂娘了。。。。。。

--->LaunchActivityItem#execute

--->ClientTransactionHandler#handleLaunchActivity
看到ActivityClientRecord   整个流程通过Intent传递信息
实际就找到Handler的msg.obj
消息状态模式，找类找的懵逼。

还没完
ClientTransactionHandler#handleLaunchActivity  怎么有找不到。记得ActivityThread 改版了extends于ClientTransactionHandler 破案了

--->ActivityThread#handleLaunchActivity-->ActivityThread#performLaunchActivity-->ActivityThread#mInstrumentation #callActivityOnCreate

---> Instrumentation#activity #performCreate

---> Activity#onCreate