iphone - iOS SDK : playing music on the background and switching views

Question

我正在尝试在我的应用程序中播放音乐。音乐播放正常，但在切换 viewControllers 并返回主菜单后，我的音乐再次播放!这意味着几个相同的声音一起播放!我该如何解决这个问题？这是我的代码:

- (void)viewDidLoad {

    NSString *music = [[NSBundle mainBundle] pathForResource:@"1music" ofType:@"mp3"];
    myMusic = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:music] error:NULL];
    myMusic.delegate = self;
    myMusic.numberOfLoops = -1; 
    [myMusic play];
}


- (IBAction) scoreView {

    ScoreViewController *scoreView = [[ScoreViewController alloc] initWithNibName:@"ScoreViewController" bundle:nil];
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:1];
    [UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:self.view cache:YES];
    [self.view addSubview: scoreView.view];
    [UIView commitAnimations];
}

编辑代码:

    - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
        if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {

            NSString * musicSonati = [[NSBundle mainBundle] pathForResource:@"music" ofType:@"mp3"];
            myMusic = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:musicSonati] error:NULL];
            myMusic.delegate = self;
            myMusic.numberOfLoops = -1;
            [myMusic play];

        }
        return self;
    }

//toggle button
- (IBAction)MusicPlaying:(id)sender {

    if ((isPlay = !isPlay))
    {

        UIImage *buttonImageNormal = [UIImage imageNamed:@"play.png"]; 
        UIImage *stretchableButtonImageNormal = [buttonImageNormal  stretchableImageWithLeftCapWidth:0 topCapHeight:0]; 
        [MusicButton setBackgroundImage:stretchableButtonImageNormal forState:UIControlStateNormal]; 
        [myMusic pause];



    }else {

        UIImage *buttonImageNormal = [UIImage imageNamed:@"pause.png"]; 
        UIImage *stretchableButtonImageNormal = [buttonImageNormal  stretchableImageWithLeftCapWidth:0 topCapHeight:0]; 
        [MusicButton setBackgroundImage:stretchableButtonImageNormal forState:UIControlStateNormal]; 
        NSLog(@"Music play");
        [myMusic play];

    } 

}

Answer 1

如果您要在多个地方播放音频，那么实现此目的的一种简单方法是在具有合成属性的委托(delegate)中声明 AVAudioPlayer 实例。如果您想在任何地方播放它，请执行以下操作:-

MyAppDelegate *app_delegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];


if(app_delegate.audioPlayer)
{
    [app_delegate.audioPlayer release];
    app_delegate.audioPlayer = nil;
}
app_delegate.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];     

如果你想停止声音，这样做:-

if(app_delegate.audioPlayer)
{
    if([app_delegate.audioPlayer isPlaying])
    {
        [app_delegate.audioPlayer stop];
        [app_delegate.audioPlayer setCurrentTime:0];
    }
}

如果已经分配或使用新的声音文件 url 再次分配它，则播放新的声音文件发布和零相同的播放器。