如何使用VideoFragment在Leanback上播放视频时将缩放模式设置为全屏

implementation 'androidx.leanback:leanback:1.1.0'
implementation 'androidx.leanback:leanback-preference:1.1.0'
implementation 'androidx.leanback:leanback-presenter:1.1.0'
implementation 'androidx.leanback:leanback-databinding:1.1.0'
implementation 'androidx.leanback:leanback-tab:1.1.0'
implementation 'androidx.leanback:leanback-transition:1.1.0'

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.VideoView;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.leanback.app.VideoFragment;

public class CustomVideoFragment extends VideoFragment {

    private VideoView mVideoView;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = super.onCreateView(inflater, container, savedInstanceState);

        mVideoView = rootView.findViewById(androidx.leanback.R.id.lb_video_surface);
        mVideoView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                | View.SYSTEM_UI_FLAG_FULLSCREEN
                | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

        mVideoView.setOnSystemUiVisibilityChangeListener(visibility -> {
            if ((visibility & View.SYSTEM_UI_FLAG_FULLSCREEN) == 0) {
                mVideoView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
            }
        });

        return rootView;
    }
}

import android.os.Bundle;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentManager;

public class MainActivity extends FragmentActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FragmentManager fragmentManager = getSupportFragmentManager();
        CustomVideoFragment videoFragment = new CustomVideoFragment();

        fragmentManager.beginTransaction()
                .replace(R.id.fragment_container, videoFragment)
                .commit();
    }
}