ios - 在制作自定义 UIButton 时以 NSException 类型的未捕获异常终止

Question

我想制作一个自定义按钮并在自定义按钮类内的选择器内提供输入，但它给我一个错误消息。我该如何修复它

我在 Playground 上测试它，因为当我运行到模拟器时应用程序崩溃了。这是 Playground 上出现的错误

terminating with uncaught exception of type NSException

这是我在 Playground 上的代码

class customButton: UIButton {

let titleName: String
let selectorName: String

init(titleName: String, selectorName: String) {
    self.titleName = titleName
    self.selectorName = selectorName
    super.init(frame: .zero)

    self.setTitle(titleName, for: .normal)
    self.addTarget(self, action: Selector(selectorName), for: .touchUpInside)
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}

class viewController: UIViewController {

override func loadView() {
    super.loadView()

    let testButton = customButton(titleName: "Test", selectorName: "handleButton")
    testButton.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(testButton)
    testButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    testButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}

func handleButton() {
    print("Pressed")
  }
}

新问题是

Cannot convert a value type of (viewController) -> () expected argument type UIViewController

I make a custom UIButton with target selector as an input, when I try to add input in the custom button it show in Xcode

Cannot convert value of type '(ProfileController) -> () -> (ProfileController)' to expected argument type 'UIViewController

这是我在 ProfileController 和自定义按钮中的代码

class CustomButton: UIButton {

let imageName: UIImage
let selectorName: String
let target: UIViewController

init(imageName: UIImage, selectorName: String, target: UIViewController) {
    self.imageName = imageName
    self.selectorName = selectorName
    self.target = target
    super.init(frame: .zero)

    self.setImage(imageName.withRenderingMode(.alwaysOriginal), for: .normal)
    self.addTarget(target, action: Selector(selectorName), for: .touchUpInside)
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}

class ProfileController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

let profileID = "profileID"

let profileImageView: UIImageView = {
    let iv = UIImageView()
    iv.image = #imageLiteral(resourceName: "581010.jpg-r_1280_720-f_jpg-q_x-xxyxx").withRenderingMode(.alwaysOriginal)
    iv.contentMode = .scaleAspectFill
    iv.clipsToBounds = true
    return iv
}()

let pickerImage = CustomButton(imageName: #imageLiteral(resourceName: "user-6"), selectorName: "handleImagePicker", target: self) //this is the error message show up in the target: self

Answer 1

您应该删除选择器作为初始化参数。您应该在创建按钮的任何位置设置目标。您还需要为 handleButton 添加 @objc，以供 Selector 调用。您的设置将如下所示，

class customButton: UIButton {

    let titleName: String

    init(titleName: String) {
        self.titleName = titleName
        super.init(frame: .zero)

        self.setTitle(titleName, for: .normal)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class viewController: UIViewController {

override func loadView() {
    super.loadView()

    let testButton = customButton(titleName: "Test")
    testButton.translatesAutoresizingMaskIntoConstraints = false
    testButton.addTarget(self, action: Selector("handleButton"), for: .touchUpInside)
    view.addSubview(testButton)
    testButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    testButton.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}

@objc func handleButton() {
    print("Pressed")
  }
}

在最新的 Swift 中，您应该将 Selector("handleButton") 更改为 #selector(handleButton)

---

如果你想坚持当前的实现，那么你需要在 customButton 初始化器中使用 target 参数，如下所示，

init(titleName: String, selectorName: String, target: UIViewController) {
    self.titleName = titleName
    self.selectorName = selectorName
    super.init(frame: .zero)

    self.setTitle(titleName, for: .normal)
    self.addTarget(target, action: Selector(selectorName), for: .touchUpInside)
}

现在您将像这样传递 ViewController 引用，

let testButton = customButton(titleName: "Test", selectorName: "handleButton", target: self)

并且不要忘记使用 objc 将 handleButton 标记为，

@objc func handleButton() {