How to move data backward from third viewcontroller to first viewcontrlloer using notification center?

Question

I have 3 view controller. I have passed object from first to second and second to third viewcontroller and now editing some data in third viewcontroller and trying send updated data object back to first viewcontroller using notification center. But I am not sure how or which method should i use to post notification which can pass data object to first viewcontrller.

For now I tried as following

    // third view controller 
    import UIKit

    protocol editContactDelegate: AnyObject {
        func updateContact(contact: Contact)
    }

    class EditViewController: UIViewController {

        @IBOutlet weak var lblName: UILabel!
        @IBOutlet weak var lblPhoneNumber: UILabel!
        @IBOutlet weak var lblEmailID: UILabel!



        var editContact: Contact?

        weak var delegate: editContactDelegate?

        override func viewDidLoad() {
            super.viewDidLoad()

            // Do any additional setup after loading the view.

            lblName.text = editContact?.name
            lblPhoneNumber.text = editContact?.phone
            lblEmailID.text = editContact?.email

        }

        @IBAction func editContact(_ sender: AnyObject) {


///??? which method should i use to post object 
         NotificationCenter.default.post(name: NSNotification.Name("Test"), object: Contact(name: "abc", position: "xyz", email: "[email protected]", phone: "updated number"))
        }

    }

//////////

// first view controller 

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, editContactDelegate {
    func updateContact(contact: Contact) {
        print(contact.email)
    }


    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        self.tableview.delegate =  self
        self.tableview.dataSource = self

        tableview.register(UINib(nibName: "ContactCell", bundle: nil), forCellReuseIdentifier: "ContactCell")

       NotificationCenter.default
            .addObserver(self,
                         selector:#selector(NotificationAct(_:)),
                         name: NSNotification.Name ("Test"),                                          object: nil)

    }


    @objc func NotificationAct(_ notification: NSNotification) {

        var abc = notification. // how to get object from third viewcontroller ???

    }
}

Answer 1

You need

let abc = notification.object as! Contact