Passing data from modal view controller to parent

class ViewController : UIViewController {
    var userName : String = " ";

    lazy var showModalButton : UIButton = {
        let button = UIButton();
        button.setTitle("show modal", for: .normal);
        button.backgroundColor = UIColor.blue;
        // add 'click event' to button
        button.addTarget(self, action: #selector(showModal), for: .touchUpInside);
        return button;
   }();

    override func viewDidLoad() {
        super.viewDidLoad()
        // add button to view controller's view.
        self.view.addSubview(self.showModalButton);
        // center the button vertically and horizontally.
        self.view.addConstraint(NSLayoutConstraint(item: self.showModalButton, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1, constant: 0));
        self.view.addConstraint(NSLayoutConstraint(item: self.showModalButton, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0));
    }

    // this is the function that is called when the button is tapped.
    func showModal()
    {
        let modalController = ModalController();
        // self the parent as a property on the child. Usually, the name of the property is 'delegate', 
        // but you can actually call it whatever you like. To help other's, you should add a comment
        // to the property mentioning the fact the it's a delegate.
        modalController.delegate = self;
        self. presentViewController( modalController, animated: true, completion: nil);
    }



}

class ModalViewController : UIViewController {

    lazy var saveButton : UIButton = {
        let button = UIButton();
        button.setTitle("save name", for: .normal);
        button.backgroundColor = UIColor.blue;
        // add 'click event' to button
        button.addTarget(self, action: #selector(saveName), for: .touchUpInside);
        return button;
    }();

    self.delegate : ViewController?;

    let nameField = UITextInput();

    override func viewDidLoad() {
        super.viewDidLoad()
        // add button to view controller's view.
        self.view.addSubview(self.saveButton);
        // center the button horizontally and place button 50 pixel below the views center point.
        self.view.addConstraint(NSLayoutConstraint(item: self.saveButton, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1, constant: 50));
        self.view.addConstraint(NSLayoutConstraint(item: self.saveButton, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0));
        // add text field to view controller's view.
        self.view.addSubview(self.nameField);
        // center the text field horizontally and vertically.
        self.view.addConstraint(NSLayoutConstraint(item: self.nameField, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1, constant: 0));
        self.view.addConstraint(NSLayoutConstraint(item: self.nameField, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0));
    }

    // this is the function that is called when the button is tapped.
    func saveName()
    {
        // pass the data from the child's text field to the parent by setting is on a property of the parent.
        self.delegate?.userName = self.nameField.text as? String;
        self.dismiss(animated: true, completion: nil);
    }



}

class ViewController: UIViewController {

    // MARK: - Property   
    @IBOutlet weak var textView: UITextView! 

    // MARK: - Life Cycle   
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    // MARK: - Navigation

   // This is your unwind Segue, and it must be a @IBAction
    @IBAction func unwindToViewController(segue: UIStoryboardSegue) {
        let source = segue.source as? SecondViewController // This is the source
        textView.text = source?.textField.text // Here we are getting the information and setting it to the textView
    }

}

class SecondViewController: UIViewController {

    // MARK: - Property
    @IBOutlet weak var textField: UITextField!

    // MARK: - Life Cycle   
    override func viewDidLoad() {
        super.viewDidLoad()
    }

}