UIBarButtonItem depending on presentation. Swift3

Question

I am facing a problem, because there are two ways how do I display my ViewController.

1. First way is performSegue(withIdentifier: "segue", sender: self)

It works fine because then I have this back button in my navigationItem:

2. Then I use this code to present the same ViewController (from another viewController than in the first case):

       let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
       let navVC = storyboard.instantiateViewController(withIdentifier: "navViewController") as! UINavigationController
       let vc = navVC.topViewController as! ViewController             
       self.present(navVC, animated: true, completion: nil)
   

but then I do not have any back button in my ViewController.

My question is: How can I keep my backButton (exactly how it is) when I use this function: performSegue(withIdentifier: "segue", sender: self) , but add button (can look different) when I use this function: self.present(navVC, animated: true, completion: nil)

Note: In my case 1 my segue is connected right to ViewController , but in case 2 I present UINavigationController and ViewController is embed in in this UINavigationController.

Edit: I tried this code, but it always prints: "1.........":

if self.presentingViewController != nil {
            print("1..........")
        } else if self.navigationController?.presentingViewController?.presentedViewController == self.navigationController  {
            return print("2.........")
        } else if self.tabBarController?.presentingViewController is UITabBarController {
            return print("3........")
        }

And also this code prints:"Else.............." :

let isPresentingInAddMealMode = presentedViewController is UINavigationController

if isPresentingInAddMealMode {
    print("FirstOption......................")

} else {
    print("Else......................")

}

If you need more info just let me know. Thank you very much.

Answer 1

I have solved it!! I put restorationIdentifier to my root navigationController and then I just check if that is navigationController with my restorationIdentifier like this:

    if self.navigationController?.restorationIdentifier == "navViewController"{
        let leftItem = UIBarButtonItem(barButtonSystemItem: .stop, target: self, action: #selector(goBack))
        self.navigationItem.leftBarButtonItem = leftItem //Adds item if id is navViewController
    }else{
       self.navigationItem.leftBarButtonItem = nil //removes it and keeps "<Back"
    }