使具有物理按键的手机能够显示Action Bar overflow

让overflow始终都显示：

public class XxxActivity{@Overrideprotected void onCreate(Bundle savedInstanceState) {...        getOverflowMenu();    }//force to show overflow menu in actionbar for android 4.4 belowprivate void getOverflowMenu() {     try {        ViewConfiguration config = ViewConfiguration.get(this);        Field menuKeyField = ViewConfiguration.class.getDeclaredField("sHasPermanentMenuKey");        if(menuKeyField != null) {            menuKeyField.setAccessible(true);            menuKeyField.setBoolean(config, false);        }    } catch (Exception e) {        e.printStackTrace();    }}}