Android系统架构图,描述一下各个层次的作用?
Activity如何与Service通信?
参考:
http://www.wanandroid.com/blog/show/2109
https://www.jianshu.com/p/91718de18979
https://www.jianshu.com/p/fb815eaf628f
https://www.jianshu.com/p/c70989bd5f29