iOS SDK：在后台播放音乐并切换视图 [英] iOS SDK : playing music on the background and switching views

问题描述

我正在尝试在我的应用程序中播放音乐。音乐工作正常，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！我怎么解决这个问题？这是我的代码：

I am trying to play music in my application. The music works fine but after switching viewControllers and returning to the main menu, my music plays again! It means several identical sounds play together! How can I solve this? Here is my code :

- (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];
}

已编辑代码：

    - (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];

    } 

}

推荐答案

确保myMusic被正确地声明为保留属性并合成然后尝试这样的事情：

Make sure myMusic is correctly declared as a retained property and synthesized then try something like this:

-(void) commonInit {
    NSString * musicSonati = [[NSBundle mainBundle] pathForResource:@"music" ofType:@"mp3"];
    self.myMusic = [[[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:musicSonati] error:NULL] autorelease];
    self.myMusic.delegate = self;
    self.myMusic.numberOfLoops = -1;
//You probably don't want to play music on init, rather defer to viewDidLoad.
//        [self.myMusic play];
}

- (id)initWithCoder:(NSCoder *)coder {
    self = [super initWithCoder:coder];
    if (self) {
        [self commonInit];
    }
    return self;
}

- (id)init {
    self = [super init];
    if (self) {
        [self commonInit];
    }
    return self;
}

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

然后在viewDidLoad中试试这个：

Then try this in your viewDidLoad:

- (void)viewDidLoad {
    ...
    if (!self.myMusic.playing) {
        [self.myMusic play];
    }
    ...
}

此外，不要忘了释放你的玩家dealloc！

Also, don't forget to release your player in dealloc!

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