如果某些活动在android中有视频播放，如何暂停背景音乐？

import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class VideoActivity extends AppCompatActivity implements SurfaceHolder.Callback, MediaPlayer.OnPreparedListener {
    private MediaPlayer mediaPlayer;
    private AudioManager audioManager;

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

        // 初始化视频播放器
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setOnPreparedListener(this);

        // 初始化音频管理器
        audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);

        // 初始化SurfaceView并设置回调
        SurfaceView surfaceView = findViewById(R.id.surfaceView);
        SurfaceHolder surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // 设置视频播放器的显示表面
        mediaPlayer.setDisplay(holder);

        try {
            // 设置视频文件路径
            mediaPlayer.setDataSource("path_to_video_file");

            // 异步准备视频播放器
            mediaPlayer.prepareAsync();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onPrepared(MediaPlayer mp) {
        // 请求音频焦点，暂停背景音乐
        audioManager.requestAudioFocus(null, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);

        // 开始播放视频
        mediaPlayer.start();
    }

    @Override
    protected void onPause() {
        super.onPause();

        // 暂停视频播放
        mediaPlayer.pause();

        // 释放音频焦点，继续播放背景音乐
        audioManager.abandonAudioFocus(null);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        // 释放视频播放器资源
        mediaPlayer.release();
    }
}