1、準備一段無聲的音訊，新建一個播放音樂的Service類，將播放模式改為無限迴圈播放。在其onDestroy方法中對自己重新啟動。

public class PlayerMusicService extends Service {
    private final static String TAG = PlayerMusicService.class.getSimpleName();
    private MediaPlayer mMediaPlayer;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Logger.d(TAG, TAG + "---->onCreate,啟動服務");
        mMediaPlayer = MediaPlayer.create(getApplicationContext(), R.raw.silent);
        mMediaPlayer.setLooping(true);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                startPlayMusic();
            }
        }).start();
        return START_STICKY;
    }

    private void startPlayMusic() {
        if (mMediaPlayer != null) {
            Logger.d(TAG, "啟動後臺播放音樂");
            mMediaPlayer.start();
        }
    }

    private void stopPlayMusic() {
        if (mMediaPlayer != null) {
            Logger.d(TAG, "關閉後臺播放音樂");
            mMediaPlayer.stop();
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        stopPlayMusic();
        Logger.d(TAG, TAG + "---->onCreate,停止服務");
        // 重啟自己
        Intent intent = new Intent(getApplicationContext(), PlayerMusicService.class);
        startService(intent);
    }
}
 

2、 在保活的DownloadServie服務類的onCreate方法中對PlayerMusicService進行啟動

 Intent intent = new Intent(this, PlayerMusicService.class);
 startService(intent);

3、在Manifest檔案中進行註冊

  <service
            android:name=".service.PlayerMusicService"
            android:enabled="true"
            android:exported="true"
            android:process=":music_service" />