ios - 为什么我的按钮不让我的选择器 View 出现？

Question

这是我之前在这里获得帮助的代码，我只是不太清楚我的代码缺少什么功能。我已将其设置为按下按钮以使选择器 View 出现，然后选择出现在标签中。但是当我单击按钮时，它不会出现选择器 View 。据我所知，问题是我缺少一个连接，该连接会触发一个连接使另一个出现，我的选择器 View 设置为隐藏，并且当它应该弹出时它会出现在堆栈 View 之上。

    import UIKit

class CalculatorViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

@IBOutlet weak var firstButton: UIButton!
@IBOutlet weak var secondButton: UIButton!
@IBOutlet weak var thirdButton: UIButton!
@IBOutlet weak var fourthButton: UIButton!
@IBOutlet weak var fifthButton: UIButton!
@IBOutlet weak var nextPageButton: UIButton!

@IBOutlet weak var firstTextField: UITextField!
@IBOutlet weak var secondTextField: UITextField!
@IBOutlet weak var thirdTextField: UITextField!
@IBOutlet weak var fourthTextField: UITextField!
@IBOutlet weak var fifthTextField: UITextField!

@IBOutlet weak var pickerView: UIPickerView!

var firstButtonDataSource = ["1", "2", "3", "4"];
var secondButtonDataSource = ["White", "Red", "Green", "Blue"];
var thirdButtonDataSource = ["Mike", "Steve", "Ben", "Peter"];
var fourthButtonDataSource = ["Large", "Medium", "Small", "Extra-small"];
var fithButtonDataSource = ["USA", "UK", "France", "Germany"];

var lastPressedButton: UIButton?

override func viewDidLoad() {
    super.viewDidLoad()

    firstButton.addTarget(self, action:#selector(buttonClicked(sender:)), for: .touchUpInside)
    secondButton.addTarget(self, action:#selector(buttonClicked(sender:)), for: .touchUpInside)
    thirdButton.addTarget(self, action:#selector(buttonClicked(sender:)), for: .touchUpInside)
    fourthButton.addTarget(self, action:#selector(buttonClicked(sender:)), for: .touchUpInside)
    fifthButton.addTarget(self, action:#selector(buttonClicked(sender:)), for: .touchUpInside)

    self.pickerView.dataSource = self;
    self.pickerView.delegate = self;
}

@objc func buttonClicked(sender:UIButton!) {

    lastPressedButton = sender

    if lastPressedButton == firstButton {
        firstTextField.inputView = pickerView
    } else if lastPressedButton == secondButton {
        secondTextField.inputView = pickerView
    } else if lastPressedButton == thirdButton {
        thirdTextField.inputView = pickerView
    } else if lastPressedButton == fourthButton {
        fourthTextField.inputView = pickerView
    } else if lastPressedButton == fifthButton {
        fifthTextField.inputView = pickerView
    }
}

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

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

    if lastPressedButton == firstButton {
        return firstButtonDataSource.count;
    } else if lastPressedButton == secondButton {
        return secondButtonDataSource.count;
    } else if lastPressedButton == thirdButton {
        return thirdButtonDataSource.count;
    } else if lastPressedButton == fourthButton {
        return fourthButtonDataSource.count;
    } else if lastPressedButton == fifthButton {
        return fithButtonDataSource.count;
    }

    return 0
}

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

    if lastPressedButton == firstButton {
        return firstButtonDataSource[row];
    } else if lastPressedButton == secondButton {
        return secondButtonDataSource[row];
    } else if lastPressedButton == thirdButton {
        return thirdButtonDataSource[row];
    } else if lastPressedButton == fourthButton {
        return fourthButtonDataSource[row];
    } else if lastPressedButton == fifthButton {
        return fithButtonDataSource[row];
    }

    return ""
}

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

    if lastPressedButton == firstButton {
        self.firstTextField.text = firstButtonDataSource[row]
    } else if lastPressedButton == secondButton {
        self.secondTextField.text = secondButtonDataSource[row]
    } else if lastPressedButton == thirdButton {
        self.thirdTextField.text = thirdButtonDataSource[row]
    } else if lastPressedButton == fourthButton {
        self.fourthTextField.text = fourthButtonDataSource[row]
    } else if lastPressedButton == fifthButton {
        self.fifthTextField.text = fithButtonDataSource[row]
    }
}
}

Answer 1

您似乎从未将正确的文本字段设置为第一响应者。

顺便说一句，所有长 if/else if/else if... 构造都会像 switch 语句一样干净，或者您可以甚至设置以按钮为键的字典，然后设置一个包含数据源和该按钮的选择器 View 的结构:

struct ButtonData {
  let buttonDataSource: [String]
  let buttonTextField: UITextField
}

let buttonsDict = [
  firstButton: ButtonData(buttonDataSource: ["1", "2", "3", "4"],
    buttonTextField: firstTextField),
  secondButton: ButtonData(buttonDataSource: ["White", "Red", "Green", "Blue"],
    buttonTextField: secondTextField),
  thirdButton: ButtonData(buttonDataSource: ["Mike", "Steve", "Ben", "Peter"],
    buttonTextField: thirdTextField),
  fourthButton: ButtonData(buttonDataSource: ["Large", "Medium", "Small", "Extra-small"],
    buttonTextField: fourthTextField),
  fifthButton: ButtonData(buttonDataSource: ["USA", "UK", "France", "Germany"],
    buttonTextField: fifthTextField)
]

然后像按钮操作这样的代码可以使用字典:

@objc func buttonClicked(sender:UIButton!) {

    lastPressedButton = sender

    guard let buttonStruct = buttonsDict[lastPressedButton] else { return }

    let textField = buttonsStruct.buttonTextField

    textField.inputView = pickerView

    //I think this the code you need to show the picker
    textField.becomeFirstResponder() 
}