Working with color and UINavigationItem's search controller

I had a very hard time figuring out how exactly to customize the search bar. Here's how I ended up doing things:

This code is in my AppDelegate class.

UISearchBar.appearance().tintColor = UIColor(named: "Button") // using this to set the text color of the 'Cancel' button since the search bar ignores the global tint color property for some reason
 
if let sky = UIColor(named: "Sky")
{
     // Search bar placeholder text color
     UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).attributedPlaceholder = NSAttributedString(string: "Search", attributes: [NSAttributedStringKey.foregroundColor: sky])
 
     // Search bar text color
     UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).defaultTextAttributes = [NSAttributedStringKey.foregroundColor.rawValue: sky]
 
     // Insertion cursor color
     UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).tintColor = sky
}
 
// Search bar clear icon
UISearchBar.appearance().setImage(UIImage(named: "clear"), for: .clear, state: .normal)

This is an extension on UIView I'm using to help with the other search bar customizations.

extension UIView
{
    func getSubview<T>(type: T.Type) -> T?
    {
        let svs = subviews.flatMap { $0.subviews }
        let element = (svs.filter { $0 is T }).first
 
        return element as? T
    }
}

And this is in the view controller.

// Changes the tint color of the magnifying glass icon, I'm calling it in ' viewDidAppear'
if let textFieldInsideSearchBar = searchController.searchBar.getSubview(type: UITextField.self), let searchIconImageView = textFieldInsideSearchBar.leftView as? UIImageView
{
     searchIconImageView.image = searchIconImageView.image?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)
     searchIconImageView.tintColor = UIColor.blue
}
 
// Changes the background color of the search bar text field, I'm calling it in 'viewDidLoad'
if let textFieldInsideSearchBar = searchController.searchBar.getSubview(type: UITextField.self)
{
     textFieldInsideSearchBar.layer.backgroundColor = UIColor.white.cgColor
 
     textFieldInsideSearchBar.layer.cornerRadius = 10.0
}

You can also change the background color of the searchBar in iOS 11 this way:

https://stackoverflow.com/a/46315974/1109892