Custom Progressbar

http://blog.csdn.net/lcore/article/details/8728298
http://my.oschina.net/u/614972/blog/144434
http://www.cnblogs.com/tianzhijiexian/p/3854105.html
http://winwyf.blog.51cto.com/4561999/857867
http://stackoverflow.com/questions/15243553/how-to-implement-this-type-of-progressbar-in-android-using-xml-file
http://www.tiemenschut.com/how-to-customize-android-progress-bars/