UINavigationBar too low when using UIScreen.main.bounds as UIWindow frame - ios

Question

I am building an iOS app, deployment target 12.1, swift 4.2. The app uses container views and has a navigation bar at the top of the main screens, preferably right under the status bar. In the launchscreen storyboard, I have constrained Navigation Bar.top to Safe.Area.Top. That works fine. But after I set the containerViewController to be the rootViewController in the AppDelegate, the navigation bar as I've constrained it in Main.storyboard (Navigation Bar.top to Safe.Area.Top) appears far below where it should be.
The only way I can get the navigation bar to appear right under the status bar is to create a custom frame for my window in AppDelegate with a negative y-value -- and that is definitely NOT a solution I'm comfortable with.
This seems to generate a y-value too low:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
window = UIWindow(frame: UIScreen.main.bounds)
let containerViewController = ContainerViewController()
window!.rootViewController = containerViewController
window!.makeKeyAndVisible()
return true
}
And this is the egregious hack that gets the navigation bar closer to where it should be:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
//window = UIWindow(frame: UIScreen.main.bounds)
let hackedFrame = CGRect(x: 0, y: -44, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
window = UIWindow(frame: hackedFrame)
let containerViewController = ContainerViewController()
window!.rootViewController = containerViewController
window!.makeKeyAndVisible()
//window!.windowLevel = UIWindow.Level.statusBar
return true
}
Screen grabs:
I'm probably missing something really obvious here, but I'd appreciate any help anyone can give.
Thanks.

Answer 1

In iOS 11 Apple introduced large titles in the navigation bar, which means that it can be stretched if pulled. You should try setting
navigationItem.largeTitleDisplayMode = .never
In your viewDidLoad, and set the prefersLargeTitles of your navigation bar to false
if #available(iOS 11.0, *) {
navigationItem.largeTitleDisplayMode = .always
navigationController?.navigationBar.prefersLargeTitles = true
}

Answer 2

try adding the navigation bar in ViewController instead of AppDelegate like this:
var screenWidth : CGFloat!
var screenHeight : CGFloat!
let screenSize: CGRect = UIScreen.main.bounds
inside ViewDidLoad:
screenWidth = screenSize.width
screenHeight = screenSize.height
navigationBar = UINavigationBar(frame: CGRect(x: 0, y: 20, width: screenWidth, height: screenWidth / 3))
for adding title and button:
view.addSubview(navigationBar)
let navItem = UINavigationItem(title: "MainController")
let doneItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.cancel, target: nil, action: #selector(DismissViewController))
navItem.leftBarButtonItem = doneItem
UINavigationBar.appearance().barTintColor = .white
navigationBar.setItems([navItem], animated: false)