Nil when transferring data from TabbarController to ViewController - ios

Question

I can’t understand what the mistake is,
an ordinary user should register, provided that everything is successful, the current user will show on TabBarController, and if you want him to convert to print("\(currentUser)"), then everything is fine. this user's protocol
Here I output to the console, everything is fine
import UIKit
class MainTabBarViewController: UITabBarController {
var currentUser: MUser = MUser(username: "fdff",
usersurname: "dfdf",
phone: "dffd",
sex: "dfb",
avatarStringURL: "fgf",
id: "gf",
bithDate: "fggf")
override func viewDidLoad() {
super.viewDidLoad()
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let messageVC = storyboard.instantiateViewController(identifier: "MessageVC") as! MessageVC
messageVC.currentUser = currentUser
print("\(currentUser)")
}
}
but you see, I pass it on and in this controller the nil issues
import UIKit
import FirebaseFirestore
class MessageVC: UITableViewController {
var chat = [MChat]()
var currentUser: MUser!
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print(chat[indexPath.row])
print("\(currentUser)") // return nil
let chatsVC = ChatsViewController(user: currentUser, chat: chat[indexPath.row])
navigationController?.pushViewController(chatsVC, animated: true)
}
}
Can anyone explain what I'm doing wrong?

Answer 1

Solution
Try to instantiate the MessageVC from the storyboard and then pass the data to it from the TabBarController.
Hold the reference of MessageVC globally outside ViewDidLoad and use it for navigation.
Example
class MainTabBarViewController: UITabBarController {
var currentUser: MUser = MUser(username: "fdff",
usersurname: "dfdf",
phone: "dffd",
sex: "dfb",
avatarStringURL: "fgf",
id: "gf",
bithDate: "fggf")
// Declare Message VC instance
var messageVC : MessageVC!
override func viewDidLoad() {
super.viewDidLoad()
// Instantiate from Storyboard
let storyboard = UIStoryboard(name: "Main", bundle: nil)
messageVC = storyboard.instantiateViewController(identifier: "VCIdentifier")
messageVC.currentUser = currentUser
print("\(currentUser)")
}
}
Update: Access Child ViewController from TabBarController
func accessMessageVC() {
// Use your viewcontroller index.
let vc = self.viewControllers![2] as! MessageVC
messageVC.currentUser = currentUser
}
Call this method from TabBarController's ViewDidLoad