demo_global_theme.swift

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).

        // Create the SwiftUI view that provides the window contents.
        
        //Use this if NavigationBarTitle is with Large Font
        
        updateAppearance()
        let contentView = ContentView().accentColor(Color.theme)

        // Use a UIHostingController as window root view controller.
        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        }
    }
    
    private func updateAppearance() {
        
        
        UINavigationBar.appearance().largeTitleTextAttributes = [.foregroundColor: UIColor.textHeaderPrimary]

        //Use this if NavigationBarTitle is with displayMode = .inline
        UINavigationBar.appearance().titleTextAttributes = [.foregroundColor: UIColor.textHeaderPrimary]
        UISwitch.appearance().onTintColor = UIColor.theme
        
        //set other like tableView etc
        
    }
}