ios - 预期标识符或 "("Objective C

Question

我对 xcode 非常陌生，我正在为一个学校项目制作一个应用程序。我正在研究背景音乐代码以在同一按钮上播放/暂停(找到代码但对其进行了一些修改)。我已经能够清除其他错误，但我不知道该怎么做......预期标识符或“(”

@implementation settingscontroller2

-(void) btnAction:(UIButton*)button{
button.selected = !button.selected;}

{ //expected Identifier or "("


if (button.selected){

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

else (!button.selected){

    // Pause
    [theAudio pause];
    return.nil
}
}

Answer 1

一旦检查这个，

-(void) btnAction:(UIButton*)button{
    button.selected = !button.selected;


    if (button.selected){

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

    else if(!button.selected){//here also one problem in your code.

        // Pause
        [theAudio pause];
        //return.nil
    }
}