#selector 函数不会为 UIDatePicker 触发

Question

我有一个非常简单的 CustomIDatePicker class 写在 Swift 5，它的顶部有一个工具栏，其中包含一个 'Done' 按钮。问题是，与此按钮关联的功能似乎从未被触发。

class CustomDatePicker: UIDatePicker {

    var zTextField: UITextField!

    let toolbar = UIToolbar()

    // bar buttons
    let doneBtn = UIBarButtonItem(barButtonSystemItem: .done, target: nil, action: #selector(donePressed(sender:)))

    convenience init(textField: UITextField) {
        self.init()

        toolbar.sizeToFit()
        toolbar.setItems([doneBtn], animated: true)

        self.datePickerMode = .date

        // link up the Text Field
        zTextField = textField
        zTextField.inputAccessoryView = toolbar
        zTextField.inputView = self
    }

    @objc func donePressed (sender: UIBarButtonItem) {
        print("done pressed") // this line fail to appear on the debugger
    }
}

一个非常简单的 ViewController 来测试 class:

class ViewController: UIViewController {

    @IBOutlet weak var theTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()

        let datePicker = CustomDatePicker(textField: theTextField)
    }
}

如有任何帮助，我们将不胜感激！

Answer 1

您需要设置目标，为此您需要在组件初始化中移动条形按钮实例化。

class CustomDatePicker: UIDatePicker {

    var zTextField: UITextField!

    let toolbar = UIToolbar()

    // bar buttons

    convenience init(textField: UITextField) {
        self.init()
        let doneBtn = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(donePressed(sender:)))
        toolbar.sizeToFit()
        toolbar.setItems([doneBtn], animated: true)

        self.datePickerMode = .date

        // link up the Text Field
        zTextField = textField
        zTextField.inputAccessoryView = toolbar
        zTextField.inputView = self
    }

    @objc func donePressed (sender: UIBarButtonItem) {
        print("done pressed") // this line fail to appear on the debugger
    }
}

#selector 函数不会为 UIDatePicker 触发

#selector function does not trigger for UIDatePicker

swift

swift5