cocos2d iOS中背景音乐的奇怪行为

我正在使用cocos2dv2，并体验到一种非常奇怪的行为

我有几首应该作为背景音乐一首接一首播放的音轨。但我注意到，当这些曲目在后台播放时，屏幕上的任何更新（渲染）都不起作用

例如，我在每个新曲目之后添加了一个新的精灵标记，但在所有曲目播放完毕之前，屏幕上不会显示任何内容。我还尝试过用CCLABELBMFont显示曲目，但在所有曲目播放完毕之前，屏幕上也不会显示任何内容

代码如下：

NSString *keyString;
CCARRAY_FOREACH([[GameManager sharedGameManager] _musicItems], keyString){
    if ([[[GameManager sharedGameManager] _soundEngine] isBackgroundMusicPlaying]) {
        int waitCycles = 0;
        while (waitCycles < AUDIO_MAX_WAITTIME) {
            [NSThread sleepForTimeInterval:0.1f];
            if (![[[GameManager sharedGameManager] _soundEngine] isBackgroundMusicPlaying]) {
                break;
            }
            waitCycles += 1;
        }
    }

    //play sound file
    CCLOG(@"Playing Sound file: %@", keyString);
    [[GameManager sharedGameManager] playBackgroundTrack:keyString];

    **EDIT:**
    /******** changed to include dispatch: start *********/
        dispatch_async(dispatch_get_main_queue(), ^{
        CCLOG(@"on main thread");
        CCSprite *marker = [CCSprite spriteWithSpriteFrameName:@"marker.png"];
        [marker setPosition:ccp(100 * count, 200)];
        [self addChild:marker z:100];
    });
    /***************** end **********************/


}

---

有人知道为什么会这样吗？

您的精灵永远不会被绘制，因为您正在阻止主线程。您应该异步调度到后台队列，并且当您想要更改UI（添加或操作精灵）时，应将其调度回主队列。

这是在主线程上运行的吗？是的，音频在后台异步加载和播放，因此它有不同的线程。有没有办法用两个线程来处理它？我想你是对的。我的实现不正确。但当我尝试使用dispatch_async或NSOperationQueue时，它没有任何帮助。也许我做得不对。我在上面添加了更改，以便以良好的格式显示：）。请告诉我我做错了什么？谢谢你的时间和帮助：D

-(void)setupAudioEngine{
    if(_hasAudioBeenInitialized){
        return; //sound engine already initialized
    }
    else{
        _hasAudioBeenInitialized = YES;
        NSOperationQueue *queue = [[NSOperationQueue new] autorelease];
        NSInvocationOperation *asyncSetupOperation = [[NSInvocationOperation alloc] initWithTarget:self
                                                                    selector:@selector(initAudioAsync) object:nil];
        [queue addOperation:asyncSetupOperation];
        [asyncSetupOperation autorelease];
    }
}

-(void)initAudioAsync{
    //Initialize audio engine asynchronously
    CCLOG(@"Audio Manager Initializing");
    _managerSoundState = kAudioManagerInitializing;

    //start audio engine
    [CDSoundEngine setMixerSampleRate:CD_SAMPLE_RATE_HIGH];

    //Init audio manager asynchronously as it can take a few seconds
    //The kAMM_FxPlusMusic mode ensure only this game plays audio
    [CDAudioManager initAsynchronously:kAMM_FxPlusMusic];

    //wait for audio manager to initialize
    while ([CDAudioManager sharedManagerState] != kAMStateInitialised) {
        [NSThread sleepForTimeInterval:0.1];
    }

    CDAudioManager *audioManager = [CDAudioManager sharedManager];
    if (audioManager.soundEngine == nil || audioManager.soundEngine.functioning == NO) {
        CCLOG(@"COCOS Dension failed to init. No audio will play");
        _managerSoundState = kAudioManagerFailed;
    }
    else{
        [audioManager setResignBehavior:kAMRBStopPlay autoHandle:YES];
        _soundEngine = [SimpleAudioEngine sharedEngine];
        _managerSoundState = kAudioManagerReady;
        CCLOG(@"COCOS Dension is ready now");
    }
}