Swift and Xcode. All UIViewControllers become black when added to TabBarController - ios

Question

I'm trying to create UITabBarController programmatically, adding multiple NavigationControllers to it. When UITabBarController contains one NavigationController - everything works as expected (see image)
But when i add multiple NavigationControllers to UITabBarController each screen becomes black (see another image )
The same black screen is shown when switching between tabs 1, 2, 3, 4 and 5.
Here's the code how UITabBarController is created
class TabBarViewController : UITabBarController{
override func viewDidLoad() {
super.viewDidLoad()
let controllers = [HistoryViewController.self, StatsViewController.self, DashboardViewController.self, ExpenseManagerViewController.self, ProfileViewController.self]
var navControllers: [UINavigationController] = []
controllers.forEach{ ctrl in
navControllers.append(getController(from: ctrl))
}
tabBar.tintColor = Color.green
viewControllers = navControllers
}
private func getController<TType: UIViewController>(from type: TType.Type) -> UINavigationController{
let ctrl = TType()
let navCtrl = UINavigationController(rootViewController: ctrl)
let ctrlName = String.init(describing: type.self).replacingOccurrences(of: "ViewController", with: String.empty)
navCtrl.tabBarItem.title = ctrlName
navCtrl.tabBarItem.image = UIImage(named: ctrlName)
navCtrl.navigationBar.topItem?.title = ctrlName
return navCtrl
}
}
Those UIViewControllers are created using "add Cocoa Touch Class" option and have assigned *.xib files with some minimum design (see one more image)
Any help regarding why all screens become black when multiple (2 and more) NavigationControllers added to TabBarController would be highly appreciated.
Thanks

Answer 1

Clearly you forget how to init the UIViewControllers with xib file:
private func getController<TType: UIViewController>(from type: TType.Type) -> UINavigationController{
let ctrl = TType(nibName: String.init(describing: type.self), bundle: nil)
let navCtrl = UINavigationController(rootViewController: ctrl)

Answer 2

First if you come from any screen then dont insert navigationbar in between that viewcontroller and tabbarcontroller and when you jump to tabbarcontroller set as rootview controller and any tab you want to open than place navigation controller in between. means dont open tabbar controller with navigationbar heirarchy but when u want to open controller with tabs then place navigation controller in between.