https://www.cnblogs.com/adm1989/archive/2012/07/13/2590231.html
https://blog.csdn.net/xiaoyu940601/article/details/53944445
https://blog.csdn.net/aikongmeng/article/details/17960217
Android显示实时时间
原文：https://www.cnblogs.com/fengjingfei/p/12763625.html
