使用 AVAudioPlayer 在后台播放声音序列

Posted 2023-02-25

【中文标题】使用 AVAudioPlayer 在后台播放声音序列

【英文标题】：Playing sequence of sounds in background with AVAudioPlayer

【发布时间】：2012-11-11 22:05:48

【问题描述】：

我想用AVAudioPlayer 播放声音序列。在前台一切正常，但在后台我有问题。

安排下一个声音后，它会在后台播放，但下一个声音初始化失败。

如何解决这个问题？

事实上，我有声音序列和起始时刻序列。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];

每次声音播放结束后都会调用audioPlayerDidFinishPlaying函数。

【参考方案1】：

音频会话设置类别后的以下行解决了问题：

[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

更多信息https://***.com/a/8071865/13441