How to add navigation interface after create a tab bar controller programmatically (Swift)

Question

How do I add a navigation interface programmatically on Swift after I created a TabBarController on AppDelegate/didFinishLaunchingWithOpt

Answer 1

To create a navigation controller use:

var navigationController = UINavigationController(rootViewController: viewController));

Then just put it in the array:

tabBarController.viewControllers = [purchaseViewController, financeViewController, navigationController]

But, you can to add UIControls to navigation bar only after view controller did load. On applicationDidFinishLaunching: it's impossible, because the navigationBar is nil. Proper way is to add controls to navigationBar in the viewDidLoad()