my navigation bar is not visible in my app - swift

Question

I am trying to set up the a navigation bar and a WKWebview in my app, the webview is present but i am not able to see the navigation bar is not visible. What am i doing wrong?
I edited my code now it functions well this is the problem remaining.
This is my code
class MyController:UIViewController, WKNavigationDelegate{
var webView: WKWebView!
#IBOutlet weak var barView: UIView!
required init(coder aDecoder: NSCoder) {
self.webView = WKWebView(frame: CGRect.zero)
super.init(coder: aDecoder)!
self.webView.navigationDelegate = self
}
override func viewDidLoad() {
super.viewDidLoad()
barView.frame = CGRect(x:0, y: 0, width: view.frame.width, height: 40)
view.insertSubview(webView, belowSubview: barView)
webView.translatesAutoresizingMaskIntoConstraints = false
let height = NSLayoutConstraint(item: webView, attribute: .height, relatedBy: .equal, toItem: view, attribute: .height, multiplier: 1, constant: 0)
let width = NSLayoutConstraint(item: webView, attribute: .width, relatedBy: .equal, toItem: view, attribute: .width, multiplier: 1, constant: 0)
view.addConstraints([height, width])
if((UserDefaults.standard.object(forKey:"language")as? String ?? "") == "en"){
let url = URL(string: "myurl")!
webView.load(URLRequest(url: url))
}
else{
let url = URL(string: "https://myurl")!
webView.load(URLRequest(url: url))
}
}
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
barView.frame = CGRect(x:0, y: 0, width: size.width, height: 40)
}
override func viewWillAppear(_ animated: Bool) {
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func btnSideMenuActn(_ sender: UIButton) {
self.pushViewControl(ViewControl:"SideMenuController")
}
}