Custom UINavigationBar gradient background and image in logo - ios

Question

I have some problems with inheriting UINavigationBar.
First of all, I have to use the same class in multiple UINavigationBar, since everything is embedded in UITabBar. So I have a UITabBar connected to 5 different UINavigationBar.
All these UINavigationBars should have a gradient background and an image as title. I tried inheriting and setting this class to each of them, but it does not work.
class NavBar: UINavigationBar {
func setupNavBar(){
self.topItem?.titleView = UIImageView(image: UIImage(named: "image"))
self.topItem?.titleView?.contentMode = .scaleAspectFit
let gradient = CAGradientLayer()
gradient.frame = self.bounds
gradient.colors = [UIColor.blue.cgColor, UIColor.blue.cgColor]
gradient.locations = [0.0, 1.0]
self.layer.insertSublayer(gradient, at: 0)
self.setNeedsLayout()
}
override func didMoveToSuperview() {
self.setupNavBar()
}
}
I have tried different combinations, but in most of them I cannot see the image. Also it happened to have a different behavior by calling the same class in different UINavigationBar, for instance in the first tab I can see the gradient, but if I change it then it is not there.
Please help me to solve this by using the subclass, I do not want to put the code in controllers.
Extra: I would also like to fill the status bar with gradient, but I can only fill static color

Answer 1

Solved by inheriting UITabBarController instead and putting gradient as backgroundImage
class NavBarController: UINavigationController {
override func viewDidLayoutSubviews() {
self.navigationBar.topItem?.titleView = UIImageView(image: UIImage(named: "image"))
self.navigationBar.topItem?.titleView?.contentMode = .scaleAspectFit
let gradient = CAGradientLayer()
var bounds = self.navigationBar.bounds
bounds.size.height += self.view.window?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0
bounds.origin.y -= self.view.window?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0
gradient.frame = bounds
gradient.colors = [UIColor.black, UIColor.white]
gradient.locations = [0.0, 1.0]
self.navigationBar.setBackgroundImage(image(fromLayer: gradient), for: .default)
}
func image(fromLayer layer: CALayer) -> UIImage {
UIGraphicsBeginImageContext(layer.frame.size)
layer.render(in: UIGraphicsGetCurrentContext()!)
let outputImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return outputImage!
}
}