Ios 添加UIApgestureRecognitor时UIImageView崩溃

当我点击图像时，它会与此消息一起崩溃

mask = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 58, 58)];
mask.image =[UIImage imageNamed:@"centerButton.png"];
mask.center = self.center;
mask.center = CGPointMake(mask.center.x, mask.center.y+3);
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(buttonPressedDown:)];
[mask addGestureRecognizer:singleTap];
[mask setMultipleTouchEnabled:YES];
[mask setUserInteractionEnabled:YES];



-(IBAction)buttonPressedDown
{
    //Connect this IBAction to touchDown
    mask.alpha = 0.5f;
    NSLog(@"tapping the center of the earth");
}

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我以编程方式绘制UI，因此Interface Builder中没有UI元素。我的UI是一个故事板，但它是空的。

您在实现buttonPressedDown:时忘记了冒号。在singleTap定义的action参数中去掉冒号，或者将冒号和参数添加到实现中

我如何注册触地赛？我想在UIImage不再被触摸时更改alpha，这就是singleTap所做的-点击是一次触摸，然后是一次触摸，因此在触摸之前，您不会调用buttonPressedDown。

mask = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 58, 58)];
mask.image =[UIImage imageNamed:@"centerButton.png"];
mask.center = self.center;
mask.center = CGPointMake(mask.center.x, mask.center.y+3);
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(buttonPressedDown:)];
[mask addGestureRecognizer:singleTap];
[mask setMultipleTouchEnabled:YES];
[mask setUserInteractionEnabled:YES];



-(IBAction)buttonPressedDown
{
    //Connect this IBAction to touchDown
    mask.alpha = 0.5f;
    NSLog(@"tapping the center of the earth");
}

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[OOTRotaryWheel buttonPressedDown:]: unrecognized selector sent to instance 0x71724e0'
*** First throw call stack: