android 调出系统menu键

Window window = getWindow();        try {            window.addFlags(WindowManager.LayoutParams.class.getField("FLAG_NEEDS_MENU_KEY").getInt(null));        }        catch (NoSuchFieldException e) {// Ignore since this field won't exist in most versions of Android        }        catch (IllegalAccessException e) {            Log.w("====", "Could not access FLAG_NEEDS_MENU_KEY in addLegacyOverflowButton()", e);        }