Navigation bar not appearing after delegation setup - ios

Question

I have a UILabel in my ViewController that has a NavigationController (let's say view controller A) with a tap gesture recognizer attached to the label. When the label is tapped another view appears (let's call it B). The user picks some text in B and the view dismisses back to A with the label text updated with the selection. So I created a delegation between A and B to get the selection. The problem is that I do not see the NavigationBar when B appears. Is there a way to fix this?
ViewController A
#IBOutlet weak var sectionName: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
let sectionLabelTap = UITapGestureRecognizer(target: self, action: #selector(labelTapped(_:)))
sectionName.isUserInteractionEnabled = true
sectionName.addGestureRecognizer(sectionLabelTap)
}
#objc func labelTapped(_ sender: UITapGestureRecognizer) {
let sectionNameVC = storyboard?.instantiateViewController(withIdentifier: "SectionName") as! SectionNameTableViewController
sectionNameVC.selectionNameDelegate = self
sectionNameVC.userData = userData
present(sectionNameVC, animated: true, completion: nil)
}

Answer 1

In order to display the Navigation bar the UIViewController needs to have a UINavigationController.
You can add that sectionNameVC ViewController into a UINavigationController to persevere the present animation.
In that case your code might look something like this:
#objc func labelTapped(_ sender: UITapGestureRecognizer) {
let sectionNameVC = storyboard?.instantiateViewController(withIdentifier: "SectionName") as! SectionNameTableViewController
sectionNameVC.selectionNameDelegate = self
sectionNameVC.userData = userData
let naviagtionController = UINavigationController(rootViewController: sectionNameVC)
present(naviagtionController, animated: true, completion: nil)
}
Or you can simply call pushViewController on the View Controller A's navigation Controller, like this:
self.navigationController?.pushViewController(sectionNameVC, animated: true)
This will add sectionNameVC into the View Controller A's navigation Controller stack. In this case the transition animation will be different, the sectionNameVC will come from your right.

Answer 2

You are missing the concept between "Presenting" View Controller & "Navigating" the View Controller. You will get the answer, once you understood the concept. Here, it is..
When you are presenting the ViewController, you are completely replacing the stack container to the new view controller.
STACK holds the addresses of the ViewControllers you push or pop via navigating.
e.g:
present(sectionNameVC, animated: true, completion: nil)
On the other hand, if you are navigating to other view controller by pushing it. In this case, you can go back to previous controller by simple popping the ViewController address from stack.
e.g:
self.navigationController?.pushViewController(sectionNameVC, animated: true)
self.navigationController?.popViewController(animated: true)
So, If you navigate then, only you will get navigation Bar.
Now, in your case, you are presenting the ViewController and hence, navigation bar is not showing.