为什么我将无法识别的选择器发送到课堂？

Question

我一直在经历所有堆栈溢出试图解决这个问题,但没有一个解决方案有效.

class ToastView: UIView {

    static func showInParent(parentView: UIView!, withText text: String, forDuration duration: double_t) {

        //Count toast views are already showing on parent. Made to show several toasts one above another
        var toastsAlreadyInParent = 0;

        for view in parentView.subviews {
            if (view.isKindOfClass(ToastView)) {
                toastsAlreadyInParent++
            }
        }

        var parentFrame = parentView.frame;

        var yOrigin = parentFrame.size.height - getDouble(toastsAlreadyInParent)

        var selfFrame = CGRectMake(parentFrame.origin.x + 20.0, yOrigin, parentFrame.size.width - 40.0, toastHeight);
        var toast = ToastView(frame: selfFrame)

        toast.textLabel.backgroundColor = UIColor.clearColor()
        toast.textLabel.textAlignment = NSTextAlignment.Center
        toast.textLabel.textColor = UIColor.whiteColor()
        toast.textLabel.numberOfLines = 2
        toast.textLabel.font = UIFont.systemFontOfSize(13.0)
        toast.addSubview(toast.textLabel)

        toast.backgroundColor = UIColor.darkGrayColor()
        toast.alpha = 0.0;
        toast.layer.cornerRadius = 4.0;
        toast.textLabel.text = text;

        parentView.addSubview(toast)
        UIView.animateWithDuration(0.4, animations: {
            toast.alpha = 0.9
            toast.textLabel.alpha = 0.9
        })

        var timer = NSTimer.scheduledTimerWithTimeInterval(duration, target: self , selector: "hideSelf:", userInfo: nil,     repeats: false)
        //toast.performSelector(Selector("hideSelf"), withObject: nil, afterDelay: duration)

    }

    static private func getDouble(toastsAlreadyInParent : Int) -> CGFloat {
        return (70.0 + toastHeight * CGFloat(toastsAlreadyInParent) + toastGap * CGFloat(toastsAlreadyInParent));
    }

    func hideSelf( timer: NSTimer) {
        UIView.animateWithDuration(0.4, animations: {
            self.alpha = 0.0
            self.textLabel.alpha = 0.0
            }, completion: { t in self.removeFromSuperview() })
    }

} 

这是我得到的错误:

NSInvalidArgumentException',原因:'+ [HonorsApp.ToastView hideSelf:]:无法识别的选择器发送到类0x10b564530'***第一次抛出调用堆栈:

我已经尝试将@objc添加到从选择器和类调用的方法,但它已经没用了

也:

Selector("hideSelf")

将方法声明为 hideSelf()

Selector("hideSelf:")

将方法声明为 hideSelf( timer: NSTimer)

还检查了该类继承自NSObject,这是通过继承UIView完成的,如果我没有错的话.

我正在使用XCode 6.4和swift 1.2

我是swift编程的新手,需要像Android中的Toast函数这样的东西,我发现这个代码,但是一旦我点击运行,错误就出现了.

我在这里先向您的帮助表示感谢.

Answer 1

既然showInParent是static函数,那么self您使用的NSTimer.scheduledTimerWithTimeInterval是指类,而不是类的实例.hideSelf如果没有查找正确的目标,iOS将不会找到实例方法.

尝试将ToastView您创建的实例传递给计时器:

var timer = NSTimer.scheduledTimerWithTimeInterval(duration, target: toast, selector: "hideSelf:", userInfo: nil, repeats: false)