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) {

        Window _window = getWindow();
        WindowManager.LayoutParams params = _window.getAttributes();
        params.systemUiVisibility = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION|View.SYSTEM_UI_FLAG_IMMERSIVE;
        _window.setAttributes(params);
    }
}