android的消息处理机制（图+源码分析）——Looper,Handler,Message

http://www.cnblogs.com/codingmyworld/archive/2011/09/12/2174255.html

还有相关的如下链接需要仔细check：

http://mindtherobot.com/blog/159/android-guts-intro-to-loopers-and-handlers/

http://www.cnblogs.com/keyindex/articles/1822463.html