Question

我正在使用cocos2d v2并遇到一种非常奇怪的行为。

我有几个音轨应该一个接一个地作为背景音乐播放。但是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）都无效。

例如，我在每个新曲目后添加了一个新的精灵标记，但在播放完所有曲目之前屏幕上没有显示任何内容。我也尝试使用CCLABELBMFont显示音轨＃但是在所有曲目播放完毕之前，屏幕上也没有显示任何内容。

以下是代码：

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 **********************/


}

修改：这是音频设置的实现

-(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");
    }
}

任何人都有想法为什么会这样？

Answer 1

你的精灵永远不会被绘制，因为你正在阻止主线程。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sprite）时，将调度回主队列。

cocos2d iOS中背景音乐的奇怪行为

1 个答案: