Android 如何 隐藏导航栏

/**

 * 隐藏虚拟按键，并且全屏 
 */  
protected void hideBottomUIMenu() {  
    //隐藏虚拟按键，并且全屏  
    if (Build.VERSION.SDK_INT > 11 && Build.VERSION.SDK_INT < 19) { // lower api  
        View v = this.getWindow().getDecorView();  
        v.setSystemUiVisibility(View.GONE);  
    } else if (Build.VERSION.SDK_INT >= 19) {  
        //for new api versions.  
        View decorView = getWindow().getDecorView();  
        int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION  
                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY | View.SYSTEM_UI_FLAG_FULLSCREEN;  
        decorView.setSystemUiVisibility(uiOptions);  
    }  
}