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可以解决。

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＆＃39;，原因：＆＃39; + [HonorsApp.ToastView hideSelf：]：无法识别的选择器发送到类0x10b564530＆＃39; ***首先抛出调用堆栈：

我尝试将@objc添加到从选择器和类调用的方法中但是它没用了

此外：

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功能一样的东西，我找到了这个代码，但是一旦我点击运行就出现了错误。

感谢您的帮助。

Answer 1

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

尝试将您创建的ToastView实例传递给计时器：

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

Answer 2

试试这段代码。

toast.performSelector(Selector("hideSelf:"), withObject: nil) 或

toast.performSelector(#selector(ClassName.hideSelf(_:)), withObject: nil) s

Answer 3

更改此行：

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

成：

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

这应该有所帮助。

为什么我将无法识别的选择器发送到课堂？

3 个答案: