应用程序处于后台时，AVAudioplayer无法正常工作

Question

我实际上正在开发一个根据用户位置播放录音的应用。我在尝试在后台使用该应用程序时遇到了一些问题。我已启用后台模式在后台播放音频，它在模拟器中运行良好。问题是，当我在背景中使用app调用我的autoplayRecord方法时，它不会播放任何记录。这是我的代码：

- (void) autoplayRecord
{
    autoplayingRecord = [_autoplayList objectAtIndex:0];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{

    loadingSong = YES;

    dispatch_async(dispatch_get_main_queue(), ^{
        [self showTitle:autoplayingRecord.title];
        [audioPlayer stop];

        //Make sure the system follows our playback status
        [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
        [[AVAudioSession sharedInstance] setActive: YES error: nil];

        [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
        [self becomeFirstResponder];
    });

    NSError *error;
    NSData *songFile = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:autoplayingRecord.audioURL] options:NSDataReadingMappedIfSafe error:&error];
    audioPlayer = [[AVAudioPlayer alloc] initWithData:songFile error:&error];
    [audioPlayer setDelegate:self];
    [audioPlayer prepareToPlay];

    loadingSong = NO;

    if (audioPlayer == nil)
    {
        dispatch_async(dispatch_get_main_queue(), ^{
            [activityIndicatorView stopAnimating];
            [self stopRecord];
        });
    }
    else
    {
        dispatch_async(dispatch_get_main_queue(), ^{
            [activityIndicatorView stopAnimating];
            [audioPlayer play];
        });
    }
    });
}