UIBarButtonItem depending on presentation. Swift3 - ios

Question

I am facing a problem, because there are two ways how do I display my ViewController.
First way is performSegue(withIdentifier: "segue", sender: self)
It works fine because then I have this back button in my navigationItem:
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

you need to check presentedViewController and add back button as below .
if ([self presentedViewController]) {
// add your back button item here
}

Answer 2

Try this:
let viewController = storyboard?.instantiateViewController(withIdentifier: "Login") as! LoginView
let customNavigation = UINavigationController(rootViewController: viewController)
customNavigation.navigationBar.tintColor = UIColor.black
self.present(customNavigation, animated: true, completion: nil)
override func viewDidLoad() {
super.viewDidLoad()
self.title = "Login"
navigationItem.leftBarButtonItem = UIBarButtonItem(image: UIImage(named: "back"), style: .plain, target: self, action: #selector(self.backButton))
}
func backButton() {
self.dismiss(animated: true, completion: nil)
}
Try to set Image in UIBarButtonItem

Answer 3

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"
}