选择器视图函数未调用

Question

我正在制作一个带有一些文本字段的应用程序，一旦按下，文本字段应该会从底部弹出一个选择器视图，并且应该显示我添加的一些数组，但不知何故，放上print语句后，我发现了最重要的两个函数，

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

和

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

我在选择器视图中放置单词的位置不运行代码。 我该如何解决？谢谢

import UIKit

class ViewController: UIViewController{
    var blocking = [Automation.blockTime.quarterHour, .halfHour, .hour, .twoHour]
    var blockingString = ["Quarter Hour", "Half Hour", "Hour", "Two Hours"]
    var startTimeString = ["5:00AM","6:30AM","5:30AM","6:00AM","7:00AM","7:30AM","8:00AM","8:30AM","9:00AM","9:30AM","10:00AM"]
    var endTimeString = ["5:00PM","6:30PM","5:30PM","6:00PM","7:00PM","7:30PM","8:00PM","8:30PM","9:00PM","9:30PM","10:00PM"]
    var startTime = [300, 390, 330, 360, 420, 450, 480, 510, 540, 570, 600]
    var endTime = [Int]()

    @IBOutlet weak var block: UITextField!
    @IBOutlet weak var endOfSchedule: UITextField!
    @IBOutlet weak var StartOfSchedule: UITextField!
    @IBOutlet weak var AppointmentTextField: UITextField!
    @IBOutlet weak var prorityTextField: UITextField!
    @IBOutlet weak var GoButton: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        createPicker()
        createToolbar()
        for EachElemnt in startTime {
            endTime.append(EachElemnt + (12 * 60))
        }
    }

    func createPicker() {
        let dayPicker = UIPickerView()
        dayPicker.delegate = self

        endOfSchedule.inputView = dayPicker
        StartOfSchedule.inputView = dayPicker
        block.inputView = dayPicker

        //Customizations
        dayPicker.backgroundColor = UIColor.darkGray
    }

    func createToolbar() {
        let toolBar = UIToolbar()
        toolBar.sizeToFit()

        //Customizations
        toolBar.barTintColor = .black
        toolBar.tintColor = .white

        let doneButton = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(ViewController.dismissKeyboard))

        toolBar.setItems([doneButton], animated: false)
        toolBar.isUserInteractionEnabled = true

        prorityTextField.inputAccessoryView = toolBar
    }

    @objc func dismissKeyboard() {
        view.endEditing(true)
    }
}

extension ViewController: UIPickerViewDelegate, UIPickerViewDataSource {
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        var returnment = Int()
        if pickerView == endOfSchedule {
            returnment = endTimeString.count
            return endTimeString.count
        }else if pickerView == StartOfSchedule {
            returnment = startTimeString.count
            return startTimeString.count
        }else if pickerView == block {
            returnment = blocking.count
            return blocking.count
        }

        return returnment

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

            var returnment = String()
            if pickerView == endOfSchedule {
                returnment = endTimeString[row]

            }else if pickerView == StartOfSchedule {
                returnment = startTimeString[row]

            }else if pickerView == block {
                returnment = blockingString[row]

            }
            print(returnment)
            return returnment
        }

        func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
            if pickerView == endOfSchedule {
                endOfSchedule.text = endTimeString[row]
            }else if pickerView == StartOfSchedule {
                StartOfSchedule.text = startTimeString[row]
            }else if pickerView == block {
                block.text = blockingString[row]
            }
        }

        func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
            var label: UILabel

            if let view = view as? UILabel {
                label = view
            } else {
                label = UILabel()
            }

            label.textColor = .white
            label.textAlignment = .center
            label.font = UIFont(name: "Menlo-Regular", size: 17)
            if pickerView == endOfSchedule {
                label.text = endOfSchedule.text
            }else if pickerView == StartOfSchedule {
                label.text = StartOfSchedule.text
            }else if pickerView == block {
                label.text = block.text
            }

            return label
        }
    }
}

Answer 1

你有几个问题。

1. 您从不设置选择器的dataSource。添加dayPicker.dataSource = self。
2. 您已经实现了titleForRow 和viewForRow。只实现其中之一。
3. 您的if 语句都不会成功，因为您将UIPickerView 变量与UITextField 实例进行比较。我很惊讶你的代码竟然能编译。

要解决最后一个问题，您需要设置所有文本字段的委托。然后实现textFieldDidBeginEditing委托方法。在那里，为文本字段设置一个属性。然后在您的所有选择器视图方法中，将该文本字段属性与您的文本字段插座进行比较，以便您知道哪个文本字段是当前文本字段。或者检查每个文本字段是否是第一响应者。

例子：

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if endOfSchedule.isFirstResponder {
        return endTimeString.count
    } else if StartOfSchedule.isFirstResponder {
        return startTimeString.count
    } else {
        return blocking.count
    }
}

最后一件事，确保您没有将其中一些方法放入另一个方法中。您发布的代码在错误的位置有一些花括号。

Answer 2

titleForRow: 没有被调用，因为您还使用了 viewForRow: 方法，这根本不可能包含在同一个委托中。您只能使用其中之一。

解决方案：在viewForRow: 中将label.text 设置为您在titleForRow: 中返回的字符串，并删除titleForRow: 方法。

Answer 3

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

    if pickerView == endOfSchedule {

        return endTimeString.count
    }else if pickerView == StartOfSchedule {

        return startTimeString.count
    }else {

        return blocking.count
    }
}                                                                             

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if pickerView == endOfSchedule {
        return endTimeString[row]

    }else if pickerView == StartOfSchedule {
        return startTimeString[row]

    }else  {
        return blockingString[row]
    }
}

尝试返回每个条件，然后尝试调试它。也许它会起作用，但您似乎错过了数据源。