getWindow().setFlags 不生效，要先執行 clearFlags

getWindow(). clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN); // 強制顯示狀态欄

        getWindow(). setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

                WindowManager.LayoutParams.FLAG_FULLSCREEN);//  去掉狀态欄