当app在后台时，如何播放项目中本地添加的mp3文件？

func applicationDidEnterBackground(_ application: UIApplication) {
    let audioSession = AVAudioSession.sharedInstance()
    do {
        try audioSession.setCategory(.playback, mode: .default, options: .mixWithOthers)
        try audioSession.setActive(true)
    } catch {
        print("Failed to set audio session category.")
    }
    
    // 播放音频
    let audioURL = Bundle.main.url(forResource: "your_mp3_file", withExtension: "mp3")
    do {
        let audioPlayer = try AVAudioPlayer(contentsOf: audioURL!)
        audioPlayer.numberOfLoops = -1 // 无限循环播放
        audioPlayer.play()
    } catch {
        print("Failed to play audio.")
    }
    
    // 创建后台任务
    var backgroundTask: UIBackgroundTaskIdentifier = .invalid
    backgroundTask = application.beginBackgroundTask(withName: "PlayAudioInBackground") {
        // 后台任务结束时执行的代码
        application.endBackgroundTask(backgroundTask)
        backgroundTask = .invalid
    }
}