Swift Selector 函數中的原始類型參數

Question

我想向我的 VC 添加動態數量的按鈕。 所以我循環遍歷我的按鈕數組模型並實例化 UIButtons。 問題在於向這些按鈕添加目標。 我想在添加目標時將字符串傳遞給選擇器，但是 Xcode 編譯器不允許我這樣做

“#selector”的參數不引用“@objc”方法、屬性或初始值設定項

@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)

除了使用自定義 UIButton 之外，還有其他解決方案嗎

Answer 1

我認為不可能做你正在嘗試的事情，你可以這樣嘗試：

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
}

我記得 UIButton 是可哈希的......

另一種選擇是擴展 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
}