Question

我正在尝试从我的UIVmageController扩展方法在我的UIImageView上添加一个手势识别器。

点击图像时我要触发的方法是在我的swift扩展中声明的类方法：

class func openPopViewWithText(text: String!) {
    print("fire!")
}

我也从我的扩展类中添加了选择器。这是我添加选择器的方式：

infoImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(UIViewController.openPopViewWithText(_:)) ))

这是我点击ImageView时出现的错误：

[XXXDisplayStatsViewController openPopViewWithText:]: unrecognized selector sent to instance 0x7fd31520ada0

我的扩展程序类中的完整代码：

public extension UIViewController {


func addInfoImageViewWithText(infoText: String){
    let margins : CGFloat = 30.0
    let infoImageView : UIImageView =  UIImageView(image: UIImage(named: "info"));
    let yOrigin : CGFloat = ((self.view.y + self.view.height) - infoImageView.height) - margins
    infoImageView.frame = CGRectMake(margins, yOrigin, infoImageView.width + 5, infoImageView.height + 5)
    self.view.insertSubview(infoImageView, atIndex: 0)
    self.view.bringSubviewToFront(infoImageView)
    infoImageView.userInteractionEnabled = true
    infoImageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(UIViewController.openPopViewWithText(_:)) ))
}

class func openPopViewWithText(text: String!) {
    print("fire!")
}
}

Answer 1

问题是，a[i:] for i in range(3) [0, 1, 2, 3, 4, 5] [1, 2, 3, 4, 5] [2, 3, 4, 5] a[:i] for i in range(3) [] [0] [0, 1] a[-i:] for i in range(3) [0, 1, 2, 3, 4, 5] [5] [4, 5] a[:i] for i in [None, -1, -2] DESIRED RESULT [0, 1, 2, 3, 4, 5] [0, 1, 2, 3, 4] [0, 1, 2, 3] a[:-i] for i in range(3) BUT CAN'T GET IT HERE [] [0, 1, 2, 3, 4] [0, 1, 2, 3] a[:i] for i in [0, -1, -2] OR HERE EITHER [] [0, 1, 2, 3, 4] [0, 1, 2, 3]函数中的第一个参数是openPopViewWithText而不是String。点击UITapGestureRecognizer手势识别器时会触发，它会将手势识别器实例传递给选择器，以便您可以跟踪其属性。所以你应该做的是将当前的函数签名更改为：

UIImageView

除此之外，您不应该使用类功能，因为您无法访问任何class func openPopViewWithText(recognizer: UITapGestureRecognizer) { print("fire!") }属性。

如何使用类方法作为选择器添加手势识别器？

1 个答案: