UIButton addTarget没有接到电话

Question

我正在尝试创建一个UIAlertController，其中包含一个UITextField。

文本字段的右侧应该有一个按钮(使用rightView属性)。该按钮应该查看图像，而不是常规文本按钮。

当我单击文本字段的按钮时，应该调用函数btnClicked，但它实际上从未被调用。

let alert = UIAlertController(title: "Testing", message: "", preferredStyle: .alert)
            
alert.addTextField { (field) in
    let chk = UIButton(type: UIButtonType.custom)
    chk.frame = CGRect(x: 2, y: 2, width: 18, height: 18)
    chk.tag = i
    chk.isUserInteractionEnabled = true
    chk.addTarget(self, action: #selector(self.btnClicked(sender:)), for: .touchUpInside)
    // I also tried the following:
    // chk.addTarget(chk, action: #selector(self.btnClicked(sender:)), for: .touchUpInside)

                    
    chk.setImage(UIImage(named: "rectangle"), for: .normal)
    chk.setImage(UIImage(named: "rectangle"), for: .selected)
    chk.setImage(UIImage(named: "rectangle"), for: .highlighted)
    chk.imageView!.contentMode = UIViewContentMode.scaleAspectFit
    chk.adjustsImageWhenHighlighted = true
                    
    field.rightView = chk
    field.rightViewMode = .always
}
            
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
            
self.present(alert, animated: true, completion: nil)

这是btnClicked函数：

@objc func btnClicked(sender: UIButton) {
    print("test")
}

现在，我只是尝试打印test，看看它是否工作，但没有任何东西被打印到控制台上。

我做错了什么吗？到目前为止，我无法在单击btnClicked按钮后调用chk函数。

Answer 1

我已经运行了您的代码，有一些编译器错误，我已经修复了它们。它工作得很完美。每当我点击按钮时，它每次都会在控制台上打印“测试”。

 func showAlert(){
   let alert = UIAlertController(title: "Testing", message: "", preferredStyle: .alert)

    alert.addTextField { (field) in
        let chk = UIButton(type: UIButton.ButtonType.custom)
        chk.frame = CGRect(x: 2, y: 2, width: 18, height: 18)
        chk.tag = 1
        chk.isUserInteractionEnabled = true
        chk.addTarget(self, action: #selector(self.btnClicked(sender:)), for: .touchUpInside)
        // I also tried the following:
        // chk.addTarget(chk, action: #selector(self.btnClicked(sender:)), for: .touchUpInside)


        chk.setImage(UIImage(named: "rectangle"), for: .normal)
        chk.setImage(UIImage(named: "rectangle"), for: .selected)
        chk.setImage(UIImage(named: "rectangle"), for: .highlighted)
        chk.imageView!.contentMode = UIView.ContentMode.scaleAspectFit
        chk.adjustsImageWhenHighlighted = true

        field.rightView = chk
        field.rightViewMode = .always
    }

    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

    self.present(alert, animated: true, completion: nil)
}

@objc func btnClicked(sender: UIButton) {
    print("test")
}

Answer 2

将目标chk更改为self (或btnClicked函数所在的位置)

chk.addTarget(self, action: #selector(self.btnClicked(sender:)), for: .touchUpInside)