keycode------------>KEYCODE_BACK,KEYCODE_MENU
event.getAction------->ACTION_DOWN,ACTION_UP,ACTION_MULTIPLE
|_____onKeyUp,onKeyDown,onKeyLongPress
http://xys289187120.blog.51cto.com/3361352/656863
http://blog.csdn.net/xys289187120/article/details/6685378
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原文：http://www.cnblogs.com/daishuguang/p/3718007.html