Android学习 RadioButton
http://blog.csdn.net/cuiran/article/details/45065477
https://www.baidu.com/s?wd=BadgeView%20RadioButton&rsv_spt=1&rsv_iqid=0xe724dde900024226&issp=1&f=8&rsv_bp=1&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_t=a06b3Wdgtne9PAZxt3%2BPXuMODWQBDeAvWAmwtCgLUKeTP1TkXPDbRThHcYlXAALUMFNH&oq=radiobutton%20findview&inputT=3245&rsv_pq=fbb1223700027a19&rsv_n=2&rsv_sug3=12&rsv_sug2=0&rsv_sug7=000&rsv_sug4=3245