Navigation between two UIViewControllers in Swift 3 programmatically

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

It is not needed to change the root view controller every time. instead of this let unitViewController = UnitViewController(unitType: unitType) let navigationController = UINavigationController(rootViewController: unitViewController) self.present(navigationController, animated: true, completion: nil) you can do let unitViewController = UnitViewController(unitType: unitType) self.navigationController?.pushViewController(unitViewController, animated: true) — dip
– dip, Commented Dec 2, 2016 at 3:06

aznelite89 · Accepted Answer · 2016-12-02 03:05:23Z

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

answered Dec 2, 2016 at 3:05

aznelite89

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5 Comments

zzheads Over a year ago

2. UINavigationBar.appearance().barTintColor = UIColor.black works 3. Nope, I have get rid of Main.storyboard and changes in LaunchScreen.storyboard doesnt have any effect

zzheads Over a year ago

And strange thing setting UINavigationBar.appearance().barTintColor to .black doesnt make NavigationBar black, it have black, but lighter color (different from main view)

aznelite89 Over a year ago

launch screen.storyboard only affect the launch screen

aznelite89 Over a year ago

@zzheads you may set the specify color with RGB value , i am using custom rgb method something like UIcolor.rgb(red:255 ,green:255 ,blue:255)

aznelite89 Over a year ago

@zzheads in your ViewController 's viewDidLoad() , add this code : navigationController?.navigationBar.isTranslucent = false

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