Activity的启动流程

handleResumeActivity

execute

startActivity

realStartActivityLocked

system_server

IPC

scheduleTransaction

ResumeActivityItem

resumeTopActivityUncheckedLocked

ActivityStackSupervisor

resumeTopActivityInnerLocked

Activity

performLaunchActivity

1. 创建activity实例2 创建Application对象，调用了Application的onCreate方法。3. activity.attach方法。4. 调用Activity的onCreate方法

LaunchActivityItem

handMessage（切到主线程）

TransactionExecutor

H

ActivityTaskManagerService

是否有进程？

Instrumentation

1. 调用生命周期onStart、onResume2. 设置视图可见（所以视图的真正可见是在onResume方法之后）

startSpecificActivityLocked

startActivityUnchecked

handleLaunchActivity

scheduleTransaction（执行在Bind线程池）

APP

是

startActivityForResult

ApplicationThread

execStartActivity

startActivityAsUser

ActivityStack

executeCallbacks

1、ClientTransaction添加了LaunchActivityItem实例2、使用ATMS的ClientLifecycleManager的scheduleTransaction方法，发送ClientTransaction（还使用clientTransaction.setLifecycleStateRequest方法添加了ResumeActivityItem）3、内部调用了 IApplicationThread的scheduleTransaction方法，即IPC操作

executeLifecycleState

ActivityThread

ActivityStarter