在同一视图控制器上的 Swift 中使用 2 个 pickerview 时，我只看到 ?-s，如何解决这个问题？

Question

我已经尝试解决这个问题好几个小时了，现在只剩下一个小问题了：

我在一个视图控制器上使用了 2 个 UI 选择器，当我尝试 select 一个（也就是我正在单击文本字段）时，我看到的只是问号，但是如果我单击其中一个，文本将出现在文本字段中。我只是看不到我在选择器中选择了什么。

我已经尝试使用普通的选择器视图，我为每个选择器使用了标签，但似乎没有任何效果。我知道它应该如何工作，我看了很多教程，但仍然缺少一些东西。你能帮我么？谢谢！

代码如下：

import UIKit

class SelectionViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

    @IBOutlet weak var ageTextField: UITextField!
    @IBOutlet weak var weightTextField: UITextField!

    @IBOutlet weak var genderTextField: UITextField!
    @IBOutlet weak var lifeStyleTextField: UITextField!

    let picker1 = UIPickerView()
    let picker2 = UIPickerView()

    var genders = ["Male", "Female"]
    var lifeStyle = ["Sitting", "Normal", "Active"]

    override func viewDidLoad() {
        super.viewDidLoad()

        picker1.dataSource = self
        picker1.delegate = self

        picker2.dataSource = self
        picker2.delegate = self

        genderTextField.inputView = picker1
        lifeStyleTextField.inputView = picker2
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func numberOfComponentsInPickerView(pickerView : UIPickerView!) -> Int{
        return 2
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
        if pickerView == picker1 {
            return genders.count
        } else {
            return lifeStyle.count
        }
    }

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {

        if pickerView == picker1 {
            return genders[row]
        } else if pickerView == picker2{
            return lifeStyle[row]
        }
        else {
            print("No pickerview selected.")
        }
        return ("Pickeview not selected")
    }

        func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
            if pickerView == picker1 {
                genderTextField.text = genders[row]
                self.view.endEditing(false)
            } else if pickerView == picker2{
                lifeStyleTextField.text = lifeStyle[row]
                self.view.endEditing(false)
            }
            else {
                print("Love love love I want your love")
            }
        }
}

这是我看到的：

Answer 1

您需要这个签名（错过了_）

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {

和numberOfComponentsInPickerView应该return1

在同一视图控制器上的 Swift 中使用 2 个 pickerview 时，我只看到 ?-s，如何解决这个问题？

I see only ?-s when using 2 pickerviews in Swift on the same view controller, how to fix this?

ios

swift

uiviewcontroller

uipickerview