In PageViewController navigation not working - ios

Question

I have 3 types of VC's , 1st Vc, 2nd VC is PageViewController with 3 pages(I added PageController to normal ViewController here), third one is FinalViewController.
1st VC has button when i click it will move to 2nd VC that is PageViewController(It has 3 pages[3 ViewConrollers] working fine).
In PageViewController after loading first VC, it has view with gestures when i tap that i want to navigate FinalViewController completely.
Here navigation not working.
My 1st VC code
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = true
}
override func viewWillDisappear(_ animated: Bool) {
self.navigationController?.navigationBar.isHidden = false
}
#IBAction func btn(_ sender: Any) {
let storyboard = self.storyboard?.instantiateViewController(withIdentifier: "NVC")
self.navigationController?.pushViewController(storyboard!, animated: true)
}
My PageViewController code
import UIKit
class NewViewController: UIViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
#IBOutlet weak var pagerController: UIPageControl!
#IBOutlet weak var pageControllerView: UIView!
// The pages it contains
var pages = [UIViewController]()
// The UIPageViewController
var pageContainer: UIPageViewController!
// Track the current index
var currentIndex: Int?
private var pendingIndex: Int?
override func viewDidLoad() {
super.viewDidLoad()
// Setup the pages
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let page1 = storyboard.instantiateViewController(withIdentifier: "ViewController") as! ViewController
let page2: UIViewController! = storyboard.instantiateViewController(withIdentifier: "SecondViewController")
let page3: UIViewController! = storyboard.instantiateViewController(withIdentifier: "ThirdViewController")
pages.append(page1)
pages.append(page2)
pages.append(page3)
page1.variable = "This is strig..."
// Create the page container
pageContainer = UIPageViewController(transitionStyle: .scroll, navigationOrientation: .horizontal, options: nil)
pageContainer.delegate = self
pageContainer.dataSource = self
pageContainer.setViewControllers([page1], direction: UIPageViewController.NavigationDirection.forward, animated: false, completion: nil)
// Add it to the view
pageControllerView.addSubview(pageContainer.view)
// Configure our custom pageControl
view.bringSubviewToFront(pagerController)
pagerController.numberOfPages = pages.count
pagerController.currentPage = 0
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - UIPageViewController delegates
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
let currentIndex = pages.firstIndex(of:viewController)!
if currentIndex == 0 {
return nil
}
let previousIndex = abs((currentIndex - 1) % pages.count)
return pages[previousIndex]
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
let currentIndex = pages.firstIndex(of:viewController)!
if currentIndex == pages.count-1 {
return nil
}
let nextIndex = abs((currentIndex + 1) % pages.count)
return pages[nextIndex]
}
func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
pendingIndex = pages.firstIndex(of:pendingViewControllers.first!)
}
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if completed {
currentIndex = pendingIndex
if let index = currentIndex {
pagerController.currentPage = index
}
}
}
}
My `ViewConroller` code means which is loading in `PageViewController`
import UIKit
class ViewController: UIViewController {
var variable = String()
#IBOutlet weak var subView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
//Add gesture to incoming call view
let incomingCallsViewTap = UITapGestureRecognizer(target: self, action: #selector(incomingCallsViewTapFunction(_:)))
self.subView!.addGestureRecognizer(incomingCallsViewTap)
}
// Tap gestrure selector fuction
#objc func incomingCallsViewTapFunction(_ sender: UITapGestureRecognizer) {
let clvc = self.storyboard?.instantiateViewController(withIdentifier: "FVC") as! FinalViewController
self.navigationController?.pushViewController(clvc, animated: false)
}
#IBAction func btn(_ sender: Any) {
print("ViewController one")
print(variable)
}
}

Answer 1

navigationViewController is nil so I had to do the following:
(UIApplication.shared.keyWindow?.rootViewController as? UINavigationController)?.pushViewController(clvc, animated: true)
// Tap gestrure selector fuction
#objc func incomingCallsViewTapFunction(_ sender: UITapGestureRecognizer) {
let clvc = self.storyboard?.instantiateViewController(withIdentifier: "FVC") as! FinalViewController
// self.navigationController?.pushViewController(clvc, animated: false)
(UIApplication.shared.keyWindow?.rootViewController as? UINavigationController)?.pushViewController(clvc, animated: true)
}