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