Question

我想在键盘上显示日期选择器视图。我这样做是使用UITextField扩展名。

我的代码：

extension UITextField {

//... other functions

func showDatePicker(){
    let datePicker = UIDatePicker()
    datePicker.datePickerMode = .date

    let toolbar = UIToolbar();
    toolbar.sizeToFit()

    let doneButton = UIBarButtonItem(title: "Pronto", style: UIBarButtonItemStyle.plain, target: self, action: #selector(UITextField.doneDatePicker(_:)))
    let spaceButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.flexibleSpace, target: nil, action: nil)
    let cancelButton = UIBarButtonItem(title: "Cancelar", style: UIBarButtonItemStyle.plain, target: self, action: #selector(UITextField.donePicker))
    toolbar.setItems([cancelButton,spaceButton,doneButton], animated: false)

    self.inputAccessoryView = toolbar

    self.inputView = datePicker

}

@objc func doneDatePicker(_ datePicker: UIDatePicker){

    let formatter = DateFormatter()
    formatter.dateFormat = "dd/MM/yyyy"
    self.text = formatter.string(from: datePicker.date)
    self.endEditing(true)
}
}

我的问题是当我点击“Pronto”按钮并执行函数doneDatePicker。我需要传递UIDatePicker（或只是日期）来显示文本字段上的日期但我收到此错误：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIBarButtonItem date]: unrecognized selector sent to instance 0x103488850'

我该如何解决这个问题？

Answer 1

无法通过选择器传递额外参数。为什么要将日期选择器传递给

void mergeSort(Node *head) {

    Node *front = NULL, *back = NULL, *fast, *slow;

    if(head == NULL || head->next == NULL)
        return;

    ...

    mergeSort(front);
    mergeSort(back);

    head = mergeLists(front, back);

}

替换

@objc func doneDatePicker(_ datePicker: UIDatePicker)

带

 let datePicker = UIDatePicker()

并将其作为单例类中的共享实例。然后在函数内部访问datePicker。

Answer 2

您应该简单地将UITextField子类化并将您的日期选择器声明为UITextField的属性，覆盖didMoveToSuperview方法并在那里进行自定义：

class DateField: UITextField {
    var date: Date?
    let datePicker = UIDatePicker()
    let formatter = DateFormatter()
    override func didMoveToSuperview() {
        datePicker.datePickerMode = .date
        formatter.dateStyle = .short
        let toolbar = UIToolbar()
        toolbar.sizeToFit()
        let done = UIBarButtonItem(title: "Pronto", style: .plain, target: self, action: #selector(doneAction))
        let space = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let cancel = UIBarButtonItem(title: "Cancelar", style: .plain, target: self, action: #selector(cancelAction))
        toolbar.setItems([cancel,space,done], animated: false)
        inputAccessoryView = toolbar
        inputView = datePicker
    }
    @objc func cancelAction(_ sender: UIBarButtonItem) {
        endEditing(true)
    }
    @objc func doneAction(_ sender: UIBarButtonItem) {
        date = datePicker.date
        text = formatter.string(from: datePicker.date)
        endEditing(true)
    }
}

如何传递日期选择器（或仅仅是日期）以在Swift中的文本字段中显示日期？

2 个答案: