Transparent navigation bar glitch - ios

Question

I need to make the navigation bar in some view controllers transparent (but with the bar buttons visible).
I wrote the following extension for that.
extension UINavigationBar {
func setTransparent(_ flag: Bool) {
if flag == true {
setBackgroundImage(UIImage(), for: .default)
shadowImage = UIImage()
backgroundColor = .clear
isTranslucent = true
} else {
setBackgroundImage(nil, for: .default)
}
}
}
The default styles for my navigation bars are as follows.
UINavigationBar.appearance().isTranslucent = false
UINavigationBar.appearance().tintColor = .white
UINavigationBar.appearance().barTintColor = UIColor(red: 45/255, green: 93/255, blue: 131/255, alpha: 1)
UINavigationBar.appearance().titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
All this works fine. But there's a problem if I have to turn off the transparent effect.
Say in the first view controller I don't need the navigation bar to be transparent.
class FirstViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.navigationBar.setTransparent(false)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.navigationBar.isTranslucent = false
}
}
I push to the second view controller from here. In here, the navigation bar is transparent.
class SecondViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.navigationBar.setTransparent(true)
}
}
Now when I pop back to the previous view controller, I have to explicitly set the isTranslucent property to false. I do that in the viewWillAppear as you can see in the first code snippet.
But the problem is, the navigation bar is black for a second when it happens.
I want this to be smooth. How do I avoid this?
Demo project uploaded here.
I tried the solution described here to a similar question. But it doesn't completely fix my issue. The black bar is gone but the navigation bar doesn't appear for a second just like before as you can see here.

Answer 1

Black navigation bar you see is actually a navigation controller view background color. Try add this code in first view controller viewDidLoad method
navigationController?.view.backgroundColor = navigationController?.navigationBar.barTintColor

Answer 2

Setting the navigation controller view background color did fix the black issue for me, but I was still having the "delay" problem when popping a view controller.
I fixed it by changing the theme of my NavigationController on the willMove method of the view controller being popped. Something like this:
override func willMove(toParent parent: UIViewController?) {
super.willMove(toParent: parent)
guard parent == nil,
let navController = self.navigationController else {
return
}
navController.navigationBar.isTranslucent = false
navController.view.backgroundColor = backgroundColor
navController.navigationBar.barTintColor = barColor
navController.navigationBar.tintColor = tintColor
}

Answer 3

Before Push I use
if let navigator = self.navigationController {
navigator.navigationBar.setBackgroundImage(UIImage(), for: .default)
navigator.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor : UIColor.black]
navigator.pushViewController(viewController, animated: true)
}
this make the glitch disappear working fine...
note in my case background color was white