iPhone：在后台播放音频播放列表？

发布于 2024-09-11 05:44:23 字数 1497 浏览 6 评论 0原文

我正在尝试使用 AVAudioPlayer 在后台播放音频文件序列。当应用程序不在后台时，它播放得很好，但是当应用程序进入后台时，它不会播放第二首歌曲。

这是我的代码：

-(void)playAudio:(NSString *)path{
    NSURL *url = [NSURL fileURLWithPath:path];

    NSError *error;
    AVAudioPlayer *ap = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
    [[AVAudioSession sharedInstance] setActive: YES error: nil];
    ap.delegate = self;

    mainController.audioPlayer = ap;
    [ap release];


    if (mainController.audioPlayer == nil)
        NSLog([error description]);
    else{


        UIBackgroundTaskIdentifier newTaskId = UIBackgroundTaskInvalid;

        [mainController.audioPlayer prepareToPlay];

        if([mainController.audioPlayer play]){

            newTaskId = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:NULL];

        }

        if (newTaskId != UIBackgroundTaskInvalid && bgTaskId != UIBackgroundTaskInvalid)
            [[UIApplication sharedApplication] endBackgroundTask: bgTaskId];

        bgTaskId = newTaskId;
    }

}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
    NSLog(@"finished now next...");
    [self playAudio:[self getNextAudio]];

}

我调试了应用程序，似乎当它要播放第二首歌曲时 [mainController.audioPlayer play] 返回 NO，这意味着它无法播放。那么你觉得怎么样？

更新

经过一些测试，似乎只有在设备锁定时它才能继续正常播放，但如果用户按下主页按钮并且应用程序进入后台，问题仍然存在

原文

I'm trying to play sequence of audio files in the background using AVAudioPlayer. When the app is not in the background it plays well, but when the app goes to the background it won't play the second song.

Here is my code:

-(void)playAudio:(NSString *)path{
    NSURL *url = [NSURL fileURLWithPath:path];

    NSError *error;
    AVAudioPlayer *ap = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error];
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
    [[AVAudioSession sharedInstance] setActive: YES error: nil];
    ap.delegate = self;

    mainController.audioPlayer = ap;
    [ap release];


    if (mainController.audioPlayer == nil)
        NSLog([error description]);
    else{


        UIBackgroundTaskIdentifier newTaskId = UIBackgroundTaskInvalid;

        [mainController.audioPlayer prepareToPlay];

        if([mainController.audioPlayer play]){

            newTaskId = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:NULL];

        }

        if (newTaskId != UIBackgroundTaskInvalid && bgTaskId != UIBackgroundTaskInvalid)
            [[UIApplication sharedApplication] endBackgroundTask: bgTaskId];

        bgTaskId = newTaskId;
    }

}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{
    NSLog(@"finished now next...");
    [self playAudio:[self getNextAudio]];

}

I debugged the app and it seems that when it's about to play the second song [mainController.audioPlayer play] returns NO, which means it can't play.
So what do you think?

UPDATE

After some testing it seems that it does continue to play properly only if the device locks, but if the user presses the home button and the app goes to the background the problem still remains

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