How to assign numbers for each UIpicker row - swift

Question

I am trying to develop a function in which the user enters a number in a TextField and based on the selection of the picker, it will calculate the number and display it either in a label or another text field. Now keep in mind, the picker has to retain String titles, but it will have different numbers for each row.
import UIKit
class ViewController: UIViewController, UIPickerViewDelegate,
UIPickerViewDataSource {
#IBOutlet weak var numberInput: UITextField!
#IBOutlet weak var pickerControl: UIPickerView!
#IBOutlet weak var pickerControl2: UIPickerView!
#IBOutlet weak var resultField: UILabel!
var pickerData = ["Logistic","Administration","Clinic"]
var pickerData2 = ["Days","Weeks","Months"]
override func viewDidLoad() {
super.viewDidLoad()
pickerControl.delegate = self
pickerControl2.delegate = self
pickerControl.delegate = self
pickerControl2.delegate = self
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView,
numberOfRowsInComponent component: Int) -> Int {
if pickerView == pickerControl {
return pickerData.count
} else if pickerView == pickerControl2 {
return pickerData2.count
}
return 1
}
func pickerView(_ pickerView: UIPickerView, titleForRow row:
Int, forComponent component: Int) -> String? {
if pickerView == pickerControl {
return pickerData[row]
} else if pickerView == pickerControl2 {
return pickerData2[row]
}
return ""
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row:
Int, inComponent component: Int) -> String? {
let entry = Float(numberInput.text!) ?? 0.0
if pickerView == pickerControl {
return (Array(pickerData)[row])
}
if pickerView == pickerControl2 {
if Array(pickerData2)[row] == "Days" {
self.resultField.text = String(entry * 3)
}
if Array(pickerData2)[row] == "Weeks" {
self.resultField.text = String(entry * 4)
}
if Array(pickerData2)[row] == "Months" {
self.resultField.text = String(entry * 6)
}
return Array(pickerData2)[row]
}
return ""
}
}

Answer 1

The function signature for pickerView(didSelect...) isn't correct, so it's not getting called. You'll see that Xcode is giving you a warning about it. That function shouldn't be returning anything.
Here's an example of how to change it:
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let entry = Float(numberInput.text ?? "") ?? 0.0
if pickerView == pickerControl {
return
}
switch pickerData2[row] {
case "Days":
self.resultField.text = String(entry * 3)
case "Weeks":
self.resultField.text = String(entry * 4)
case "Months":
self.resultField.text = String(entry * 6)
default:
break
}
}
You'll note that I also used a switch statement, which I think is a little cleaner looking. But, if you didn't and stuck to your if/else, you don't have to use Array() for everything -- you can do things like if pickerControl2[row] == "Days" { }
You could clean things up even further by defining pickerData2 as:
var pickerData2 : [(title: String, value: Float)] = [(title: "Days",value: 3),(title: "Weeks",value: 4),(title: "Months", value:6)]
Then, in titleForRow, you could return pickerData2[row].title
and later, in didSelectRow:
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let entry = Float(numberInput.text ?? "") ?? 0.0
if pickerView == pickerControl {
return
}
self.resultField.text = String(entry * pickerData2[row].value)
}