Changing the population of one picker view depending on which textfield is used

Question

I am new to Swift. To fill some Textfields in my app, I want to use one picker view which changes its population depending on which textfield I want to fill. My Problem is, that the function textFieldShouldBeginEditing seems not to work. The variable textFieldName doesn't change its name. Unfortunately all the code I found here is only for Objective-C. I hope you can help me bring this code to work.

Here is my code:

@IBOutlet weak var Stadt: UITextField!
@IBOutlet weak var Untergrund: UITextField!
@IBOutlet weak var Groesse: UITextField!
@IBOutlet weak var AnzToreKoerbe: UITextField!
@IBOutlet weak var Platzart: UITextField!
var UntergrundArray = ["Kunstrasen Sand", "Kunstrasen Granulat", "Rasen", "Tartan", "Teer"]
var StadtArray = ["Norderstedt", "Hamburg", "Berlin", "München"]
var GroesseArray = ["1 vs 1", "2 vs 2", "3 vs 3", "4 vs 4", "5 vs 5", "6 vs 6", "7 vs 7"]
var AnzTorKoerbe = ["1", "2", "3", "4"]
var Art = ["Fußball", "Basketball"]
var textFieldName = "Stadt1"

func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool{
    if textField.tag == 1{
        textFieldName = "Stadt1"
    }else if textField.tag == 2{
        textFieldName = "Untergrund1"
    }else if textField.tag == 3 {
        textFieldName = "Groesse1"
    }else if textField.tag == 4 {
        textFieldName = "AnzToreKoerbe1"
    }else if textField.tag == 5 {
        textFieldName = "Platzart1"
    }

    return true;
}

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

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if (textFieldName.isEqual("Stadt1")) {
        return StadtArray.count
    }else if (textFieldName.isEqual("Untergrund1")) {
        return UntergrundArray.count
    }else if (textFieldName.isEqual("Groesse1")) {
        return GroesseArray.count
    }else if (textFieldName.isEqual("AnzToreKoerbe1")) {
        return AnzTorKoerbe.count
    }else  {
        return Art.count
    }
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if (textFieldName.isEqual("Stadt1")) {
        return StadtArray [row]
    }else if (textFieldName.isEqual("Untergrund1")) {
        return UntergrundArray [row]
    }else if (textFieldName.isEqual("Groesse1")) {
        return GroesseArray [row]
    }else if (textFieldName.isEqual("AnzToreKoerbe1")) {
        return AnzTorKoerbe [row]
    }else  {
       return Art [row]
    }
}

Answer 1

You need to called reloadAllComponents at the end of the textFieldShouldBeginEditing method.

func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool{
    if textField.tag == 1{
        textFieldName = "Stadt1"
    }else if textField.tag == 2{
        textFieldName = "Untergrund1"
    }else if textField.tag == 3 {
        textFieldName = "Groesse1"
    }else if textField.tag == 4 {
        textFieldName = "AnzToreKoerbe1"
    }else if textField.tag == 5 {
        textFieldName = "Platzart1"
    }

    somePickerViewProperty.reloadAllComponents()

    return true;
}

Replace somePickerViewProperty with the name of your UIPickerView outlet.

There also a much simpler way to write your code:

var UntergrundArray = ["Kunstrasen Sand", "Kunstrasen Granulat", "Rasen", "Tartan", "Teer"]
var StadtArray = ["Norderstedt", "Hamburg", "Berlin", "München"]
var GroesseArray = ["1 vs 1", "2 vs 2", "3 vs 3", "4 vs 4", "5 vs 5", "6 vs 6", "7 vs 7"]
var AnzTorKoerbe = ["1", "2", "3", "4"]
var Art = ["Fußball", "Basketball"]
var currentData = StadtArray

func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool{
    if textField.tag == 1{
        currentData = StadtArray
    }else if textField.tag == 2{
        currentData = UntergrundArray
    }else if textField.tag == 3 {
        currentData = GroesseArray
    }else if textField.tag == 4 {
        currentData = AnzTorKoerbe
    }else if textField.tag == 5 {
        currentData = Art
    }

    somePickerViewProperty.reloadAllComponents()

    return true;
}

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

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

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return currentData[row]
}

Answer 2

Have you set the UITextField delegate to self ? I can't see it in the code you provided and the methods such as textFieldShouldBeginEditing won't be called if the delegate is not set.