Create a custom UINavigationcontroller class - ios

Question

I have done the following customisation to my embedded UINavigationcontroller. I've done this in the view controller of the view that will show up as first.
However I'm trying to clean it up so that I don't have this all in my UIView class by creating a separate class that will take care of this. The code I'm currently using
self.navigationController?.navigationBar.setBackgroundImage(UIImage(named: "navigation.background"), for: .default)
let backButton = UIImage(named: "Back.button")?.withRenderingMode(.alwaysOriginal)
let backButtonHigh = UIImage(named: "Back.button.highlighted")?.withRenderingMode(.alwaysOriginal)
self.navigationController?.navigationBar.backIndicatorImage = backButton
self.navigationController?.navigationBar.backIndicatorTransitionMaskImage = backButtonHigh
self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
What I've tried to do is extend the UInavigationcontroller in a new class like this
class RSRNavigationController: UINavigationController{
override func viewDidLoad() {
super.viewDidLoad()
self.navigationController?.navigationBar.setBackgroundImage(UIImage(named: "navigation.background"), for: .default)
let backButton = UIImage(named: "Back.button")?.withRenderingMode(.alwaysOriginal)
let backButtonHigh = UIImage(named: "Back.button.highlighted")?.withRenderingMode(.alwaysOriginal)
self.navigationController?.navigationBar.backIndicatorImage = backButton
self.navigationController?.navigationBar.backIndicatorTransitionMaskImage = backButtonHigh
self.navigationItem.backBarButtonItem = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
}
}
this doesn't work. It will run without problems but it won't actually do anything.
I've also tried to do the following
class RSRNavigationController: UINavigationBar{
override func draw(_ rect: CGRect) {
super.draw(rect)
self.setBackgroundImage(UIImage(named: "navigation.background"), for: .default)
let backButton = UIImage(named: "Back.button")?.withRenderingMode(.alwaysOriginal)
let backButtonHigh = UIImage(named: "Back.button.highlighted")?.withRenderingMode(.alwaysOriginal)
self.backIndicatorImage = backButton
self.backIndicatorTransitionMaskImage = backButtonHigh
//self.backItem = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
}
However I can't seem to set the title for the back button.
Does anyone know how to fix this?

Answer 1

Your problem lies here, when you reference navigationController INSIDE your custom navigationController class
Instead of doing
self.navigationController?.navigationBar.backIndicatorImage = backButton
do this
self.navigationBar.backIndicatorImage = backButton
Reason?
Because when you extend your custom class by UINavigationController, it becomes a navigationController itself. And by doing self.navigationController you are telling your app to look for a navigationController within which your custom navigationCOntroller resides. Ofcourse such a nav controller does not exist because your custom navController is the main or the top navController of the app. So just remove the self.navigationController part from your custom class, the rest of the code that you have written in your viewDidLoad should work good.
If you still have any questions feel free to ask

Answer 2

You do not change these properties in the navigation controller itself, you change it in the viewController that is embedded inside a navigation controller.
These customization has to be done in a parent ViewController of your view controllers.
This Answer has more info:
https://stackoverflow.com/a/16913435/4004429

Answer 3

if you just want to custom the backButton of the navigationBar,you can add this code in your child view controller :
func setupLeftBarItem() -> Void {
let originalImage = UIImage.init(named: "leftBatItem")?.withRenderingMode(.alwaysOriginal)
let leftBarItem = UIBarButtonItem.init(image: originalImage, style: .done, target: self, action: #selector(leftBarButtonItemDidTouch))
navigationItem.leftBarButtonItem = leftBarItem
}
func leftBarButtonItemDidTouch() -> Void {
_ = navigationController?.popViewController(animated: true)
}