Activity.startActivity(Intent intent)—-Activity.startActivityForResult(Intent intent)—-Instrumentation.execStartActivity()—-ActivityManagerNative.getDefault().startActivity—-ActivityManagerService—-Binder—-IActivityManager—-ActivityManagerProxy—-ActivityManagerService.startActivity—-ActivityManagerService.startActivityAsUser设置了userId—–ActivityStackSuperviso.startActivityMayWait主要进行了Intent的检查—-ActivityStackSuperviso.startActivityLocked生成ActivityRecord—–ActivityStackSuperviso.startActivityUncheckedLocked首先判断了启动模式——上面的步骤完成了Activity的目标栈的判断(targetStack)——ActivityStack.startActivityLocked将Activity添加到了栈顶，初始化了WindowManager——–StackSupervisor.resumeTopActivitiesLocked判断目标任务栈是否在前——ActivityStack.resumeTopActivityLocked确保当前栈顶的Activity是否resumed——-ActivityStack.resumeTopActivityInnerLocked 1，首先让现在正在运行的Activity调用startPausingLocked进入pause状态 2.如果要启动的Activity不为空且所在的进程存在的话，所在的进程执行scheduleResumeActivity启动Activity 3.如果Activity为空，所在的进程不存在，执行ActivityStackSupervisor.startSpecificActivityLocked
ActivityStack.startPausingLocked——-ApplicationThread.schedulePauseActivity主要handler发送消息—–ApplicationThread.handlePauseActivity—-ApplicationThread.performPauseActivity—– callCallActivityOnSaveInstanceState(r)—-Instrumentation.callActivityOnPause—Activity.performPause—Activity.onPause()
ApplicationThread.handleReusmeActivity—-ApplicationThread.performReusmeActivity—– Instrumentation.callActivityOnReusme—Activity.performReusme—Activity.onReusme()
ActivityStackSupervisor.startSpecificActivityLocked——ActivityManagerService.startProcessLocked—–Process.start方法，并且传入类名android.app.ActivityThread——-startViaZygote—–zygoteSendArgsAndGetResult最后通过Zygote孵化出了我们刚才传入的ActivityThread，也就是我们很熟悉的应用入口进程,来到它的main方法—-ActivityThread.main()—— Looper.prepareMainLooper()Looper.loop();----ActivityThread thread = new ActivityThread(); thread.attach(false)---------ActivityManagerService.attachApplication----------ActivityManagerService.attachApplicationLocked-------ActivityStackSupervisor.realStartActivityLocked-------ApplicationThread.scheduleLaunchActivity-----ActivityThread.handleLaunchActivity----ActivityThread.performLaunchActivity----packageInfo.getClassLoader() mInstrumentation.newActivity----- activity.attach(---- mInstrumentation.callActivityOnCreate activity.performStart(); mInstrumentation.callActivityOnRestoreInstanceState( prePerformCreate(activity); activity.performCreate(icicle, persistentState); postPerformCreate(activity);---activity.performCreate()----activity.Create()
Looper.loop();----ActivityThread thread = new ActivityThread(); thread.attach(false)---------ActivityManagerService.attachApplication----------ActivityManagerService.attachApplicationLocked-------ActivityStackSupervisor.realStartActivityLocked-------ApplicationThread.scheduleLaunchActivity-----ActivityThread.handleLaunchActivity----ActivityThread.performLaunchActivity----packageInfo.getClassLoader() mInstrumentation.newActivity----- activity.attach(---- mInstrumentation.callActivityOnCreate activity.performStart(); mInstrumentation.callActivityOnRestoreInstanceState( prePerformCreate(activity); activity.performCreate(icicle, persistentState); postPerformCreate(activity);---activity.performCreate()----activity.Create()