ios - 使用AVAudioPlayer在后台播放声音序列

Question

我想使用AVAudioPlayer播放声音序列。前台都可以，但是在后台我有问题。

安排下一个声音后，它会在后台播放，但是下一个声音初始化失败。

如何解决这个问题？

实际上，我有声音的顺序和开始时刻的顺序。当用户触摸按钮应用程序开始播放声音时。

我使用以下代码:

- (void)soundScheduleNext
{
    NSURL * url = ...; // get url of next sound file

    if (soundPlayer == nil)
        soundPlayer = [AVAudioPlayer alloc];
    soundPlayer = [soundPlayer initWithContentsOfURL:url error:nil];
    soundPlayer.delegate = self;

    AVAudioSession * audioSession = [AVAudioSession sharedInstance];
    [audioSession setCategory:AVAudioSessionCategoryPlayback error:nil];

    // if this is a first element of sound sequence...
    if (soundSeqNext == 0)
    {
        // ... play right now
        [soundPlayer prepareToPlay];
        soundStartMoment = [soundPlayer deviceCurrentTime];

        [soundPlayer play];
    } else {
        BOOL prepareToPlayOk = [soundPlayer prepareToPlay];

        // when second element of sequence play - prepareToPlayOk is YES; when third - prepareToPlayOk is NO :(
        NSLog(@"soundScheduleNext: prepareToPlayOk = %d", (int)prepareToPlayOk, nil);

        NSTimeInterval timeMoment = ... ; // get moment of time for next sound
        [soundPlayer playAtTime:timeMoment];
    }
    soundSeqNext++;
}

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
    [self soundScheduleNext];
}

声音播放结束后，每次都会调用 audioPlayerDidFinishPlaying函数。

Answer 1

音频 session 设置类别后的以下行解决了该问题:

[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

有关更多信息，请访问 https://stackoverflow.com/a/8071865/13441