How to save data with segues in multi storyboard app?

Question

I am very very new to coding and I am trying to make a simple app. The app is kind of questionnaire, it is going to ask you a questions and you have to put the answer in textField. The problem is when you try to go back to the previous page the text you've put in textField disappears. I want the text to stay there if you decide to change your answer some question.

This is the first view:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }
        
    @IBAction func startedButtonPressed(_ sender: UIButton) {
    
    self.performSegue(withIdentifier: "goToPageTwo", sender: self)
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?)
    {
        if segue.identifier == "goToPageTwo" {
            let destinationVC = segue.destination as! PageTwoViewController

and this is the second page view:

import UIKit

class PageTwoViewController: UIViewController {
    
    var textBox: String?
    @IBOutlet weak var textFieldOne: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func backButtonPressed(_ sender: UIButton) {
        self.dismiss(animated: true, completion: nil)
    }

Answer 1

What you can do is, you can use a callBack closure for this :

1. define a CallBack variable of type ((String) -> Void) in PageTwoViewController

2. In prepare(for:, sender) assign a closure to callBack variable of PageViewController instance.

   class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() } var firstAnswer: String? // NEW_LINE_ADDED @IBAction func startedButtonPressed(_ sender: UIButton) {

        self.performSegue(withIdentifier: "goToPageTwo", sender: self)
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "goToPageTwo" {
            let destinationVC = segue.destination as! PageTwoViewController
            destinationVC.textBox = firstAnswer //NEW_LINE_ADDED
            destinationVC.callBack = { answer in //NEW_LINE_ADDED
                self.firstAnswer = answer //NEW_LINE_ADDED
            }
        }
    }
   

   }

In PageTwoViewController do this

class PageTwoViewController: UIViewController {
var textBox: String?
var callBack: ((String)-> Void) //NEW_LINE_ADDED
@IBOutlet weak var textFieldOne: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    textfieldOne.text = textBox ?? ""   //NEW_LINE_ADDED
}

@IBAction func backButtonPressed(_ sender: UIButton) {
    callBack?(textfieldOne.text ?? "") //NEW_LINE_ADDED
    self.dismiss(animated: true, completion: nil)
}