Navigation between two UIViewControllers in Swift 3 programmatically - swift

Question

In my app have two UIViewControllers (first, where user choose character, and second, where characters info is shown).
Trying do everything from code. So my code:
AppDelegate.swift:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
self.window = UIWindow(frame: UIScreen.main.bounds)
guard let window = self.window else {
return false
}
UIApplication.shared.statusBarStyle = .lightContent
let viewController = ViewController()
let navigationController = UINavigationController(rootViewController: viewController)
window.rootViewController = navigationController
window.makeKeyAndVisible()
return true
}
ViewController: UIViewController
...
func buttonPressed(sender: UIButton) {
guard let typeName = sender.title(for: .normal), let unitType = UnitType(rawValue: typeName) else {
return
}
let unitViewController = UnitViewController(unitType: unitType)
let navigationController = UINavigationController(rootViewController: unitViewController)
self.present(navigationController, animated: true, completion: nil)
}
And UnitViewController: UIViewController (where chosen character's info is shown):
...
fileprivate func setupNavigationBar() {
let backButton = UIBarButtonItem(title: "<", style: .plain, target: self, action: #selector(backToViewController(sender:)))
self.navigationItem.setLeftBarButton(backButton, animated: true)
self.navigationItem.titleView?.backgroundColor = AppColor.Black.color
self.navigationItem.titleView?.tintColor = .white
self.navigationItem.title = "\(self.unitType.rawValue)"
}
func backToViewController(sender: AnyObject) {
self.dismiss(animated: true) {
let viewController = ViewController()
let navigationController = UINavigationController(rootViewController: viewController)
self.present(navigationController, animated: true, completion: nil)
}
}
So I have two screens:
Well, and I have some questions:
1. Getting
2016-12-02 05:48:21.855 The API Awakens[16402:551729] Warning: Attempt
to present on
whose view is not
in the window hierarchy!
warning when press 'back' button in UnitViewController. What I am doing wrong?
Gray background color and black color of NavigationBar. How change it to black and white?
How get 'system' back button for UIBarButtonItem, not just .plain with title "<"? So my UnitViewController navigation bar should looks like this:
Any help will be greatly appreciated!
UPDATE 1:
1. Warning gone, thanks to #dip
2. Made navigation bar dark, thanks to #aznelite89.
But, there is my code in AppDelegate.swift:
UINavigationBar.appearance().barTintColor = AppColor.Black.color
AppColor.Black is exact same color I'm using for background in ViewController, but that how it looks now:
Looks like alpha of NavigationBar is not 1.0...
UPDATE 2:
Different between color of NavigationBar and color I've used is 13 in RGB values, so I've hacked it setting color of NavigationBar with RGB value less by 13 than original color... It's ok now

Answer 1

Try this :-
let viewController = ViewController()
viewController.modalPresentationStyle = .overCurrentContext
window?.rootViewController?.present(viewController, animated: true, completion: nil)
Add this in app delegate.swift :-
UINavigationBar.appearance().barTintColor = UIColor.black
You may change these attributes on your storyboard attribute inspector