Android Framework- AMS/ATMS/AS/A

1. ActivityManagerService（AMS）:

处理来自 ActivityManager的调用（App 端的调用），
然后转发给 ATMS处理
frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java

2. ActivityTaskManagerService（ATMS）:

处理来自AMS 的请求， 又会转发给 ASC/ 或者AS 处理
frameworks/base/services/core/java/com/android/server/wm/ActivityTaskManagerService.java

3. ActivityStarter(AS)

真正执行启动Activity
frameworks/base/services/core/java/com/android/server/wm/ActivityStarter.java

4. ActivityStartController(ASC)

创建并持有 AS 对象.
并做一些例外处理再交给 AS 最终启动.
frameworks/base/services/core/java/com/android/server/wm/ActivityStartController.java