Activity启动

基于Api 30

一:activity启动

   1. activity.startActivity(Intent intent); ->startActivity(intent, null);
    ->startActivityForResult(intent, requestCode, null);->mInstrumentation.execStartActivity()
    // ActivityTaskManagerService
    ->ActivityTaskManager.getService().startActivity();->startActivityAsUser()->startActivityAsUser()
    ->getActivityStartController().obtainStarter().execute()->mFactory.obtain().setIntent().setReason().
        getActivityStartController() => ActivityStartController(DefaultFactory())
    ->ActivityStarter.execute()->executeRequest()->startActivityUnchecked()->startActivityInner()   
        ->resumeTopActivityUncheckedLocked()
        //Activity没有被添加到进程返回false
         if (next.attachedToProcess()) {
                } else {
                    mStackSupervisor.startSpecificActivity(next, true, true);
                }


        //没有被添加到进程中
        ->realStartActivityLocked()
        ->clientTransaction.addCallback(LaunchActivityItem.obtain(new Intent(r.intent)
        ->mService.getLifecycleManager().scheduleTransaction(clientTransaction)
        ->ApplicationThread.scheduleTransaction() -> sendMessage(ActivityThread.H.EXECUTE_TRANSACTION, transaction)
        ->mTransactionExecutor.execute(transaction);
        ->client.handleLaunchActivity()
        ->ActivityThread.handleLaunchActivity()->performLaunchActivity()
        ->mInstrumentation.newActivity()
        ->Activity activity = (Activity)clazz.newInstance()
            if (application == null) {
                        application = new Application();
                 }
                 activity.attach()
        
        
    ->mRootWindowContainer.resumeFocusedStacksTopActivities()
        ////进程不存在   
    ->2.startProcessAsync() ->ActivityManagerService.startProcess()->startProcessLocked->handleProcessStartedLocked
        ->ProcessList : mService.mHandler.sendMessageDelayed(msg, usingWrapper) PROC_START_TIMEOUT_MSG
                ->processStartTimedOutLocked(ProcessRecord)->
        
        //app进程存在   
    ->1.realStartActivityLocked()
            
    
        
             //上一个activity的pause 和下一个activity的resume
    ->resumeTopActivityInnerLocked()->startPausingLocked()
    //mAtmService ActivityTaskManagerService  getLifecycleManager()=>ClientLifecycleManager
    ->mAtmService.getLifecycleManager().scheduleTransaction()
    // transaction => ClientTransaction   mClient =>ActivityThread.ApplicationThread
    ->transaction.schedule();->mClient.scheduleTransaction(this);
    //ActivityThread extends ClientTransactionHandler
    ->ClientTransactionHandler.scheduleTransaction()
    ->sendMessage(ActivityThread.H.EXECUTE_TRANSACTION, transaction);   
    ->mTransactionExecutor.execute(transaction);
    ->executeCallbacks()
    ->performLifecycleSequence()
        mTransactionHandler.handleLaunchActivity()
        mTransactionHandler.handleStartActivity
        mTransactionHandler.handleResumeActivity
        mTransactionHandler.handlePauseActivity
        mTransactionHandler.handleStopActivity
        mTransactionHandler.handleDestroyActivity
        mTransactionHandler.performRestartActivity  

    ->handleLaunchActivity()->performLaunchActivity()
    ->mInstrumentation.newActivity(cl, component.getClassName(), r.intent)
    ->mInstrumentation.callActivityOnCreate()
    ->activity.performCreate(icicle, persistentState);
    ->performCreate()->onCreate()