Swift Selector 函数中的原始类型参数

Question

我想向我的 VC 添加动态数量的按钮。 所以我循环遍历我的按钮数组模型并实例化 UIButtons。 问题在于向这些按钮添加目标。 我想在添加目标时将字符串传递给选择器，但是 Xcode 编译器不允许我这样做

“#selector”的参数不引用“@objc”方法、属性或初始值设定项

@objc func didTapOnButton(url: String) { }
let button = UIButton()
button.addTarget(self, action: #selector(didTapOnButton(url: "Random string which is different for every bbutton ")), for: .touchUpInside)

除了使用自定义 UIButton 之外，还有其他解决方案吗

Answer 1

我认为不可能做你正在尝试的事情，你可以这样尝试：

var buttons: [UIButton: String] = []

let button = UIButton()
let urlString = "Random string which is different for every button"
buttons[button] = urlString
button.addTarget(self, action: #selector(didTapOnButton), for: .touchUpInside

@objc func didTapOnButton(sender: UIButton) { 
    let urlString = self.buttons[sender]
    // Do something with my URL
}

我记得 UIButton 是可哈希的......

另一种选择是扩展 UIButton 以保存您想要的信息：

extension UIButton {
     private static var _urlStringComputedProperty = [String: String]()
     var urlString String {
        get {
            let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
            return Self._urlStringComputedProperty[tmpAddress]
        }
        set(newValue) {
            let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
            Self._urlStringComputedProperty[tmpAddress] = newValue
        }
     }
}

let button = UIButton()
button.urlString = "Random string which is different for every button"
button.addTarget(self, action: #selector(didTapOnButton), for: .touchUpInside

@objc func didTapOnButton(sender: UIButton) { 
    let urlString = sender.urlString
    // Do something with my URL
}