registerForContextMenu 注册上下文菜单 对于长按某些视图(例如Listview等)以后便能弹出次上下文菜单
覆写以下2个方法
1、public boolean onContextItemSelected(MenuItem item)
item.gettitle().tostring() 取出选中上下文菜单的内容
2、public void onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo)