@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

//        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//設定成全屏模式
//        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);//豎屏
//
 
設定螢幕為橫屏
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

      setContentView(R.layout.activity_main);

}

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        //判斷是否有焦點
        if(hasFocus && Build.VERSION.SDK_INT >= 19){
            View decorView 
 
= getWindow().getDecorView();
            decorView.setSystemUiVisibility(
                    View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                    |View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                    |View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                    |View.SYSTEM_UI_FLAG_HIDE_NAVIGATION//隱藏nav欄
                    
 
|View.SYSTEM_UI_FLAG_FULLSCREEN//隱藏狀態列
                    |View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
            );

        }
    }