ios - UiPickerview 值在 swift 中显示为问号 ("?"- 但在将其分配给文本框时获得正确的值

Question

//向下滚动选择器 View 时，我能够在文本框中看到正确的值。但是选择器 View 显示为“？” (问号)。我对需要将 pickerview 作为输入 View 分配给文本框的位置感到困惑。但这对我面临的错误仍然没有任何意义。

我正在使用 Xcode 9 和 Swift 3.2。

class BillDetailsViewController: UIViewController ,UITextFieldDelegate,UIPickerViewDelegate,UIPickerViewDataSource{

  //Variables  Declaration

  //Picker view outlet
  @IBOutlet var datePickerView: UIPickerView!

  //Picker view datasource - integer array
  var integerArray = [Int](1899...2500)

  //Textbox where picked value to be shown
  @IBOutlet var txtPaidYear: UITextField!

  //ViewLoad
  override func viewDidLoad() {

    super.viewDidLoad()
    self.hideKeyboardWhenTappedAround()

    datePickerView.isHidden = true
    datePickerView.reloadAllComponents()
    datePickerView.dataSource = self
    datePickerView.delegate = self
    txtPaidYear.inputView = datePickerView
  }

  //picker view delegate functions

  public func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
  }

  public func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return integerArray.count
  }

  public func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
    let pickerValue: String = String(integerArray[row])
    return pickerValue
  }

  public func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    txtPaidYear.text = String(integerArray[row])
    self.datePickerView.reloadAllComponents()
  }
}

Answer 1

****你必须像这样改变方法，它肯定会起作用。**并删除您正在使用的 TextField 的委托(delegate)..**

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent 组件: Int) -> Int {

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> 字符串？ {

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {