How to change tintColor of whole app? SwiftUI

Question

So, I am supporting three themes in my app, each with different tintColors. I\'m using @EnvironmetObject to track changes. However, I can\'t use it on SceneDelegate.swift fi

Answer 1

You can achieve it by calling

UIView.appearance(whenContainedInInstancesOf: [UIAlertController.self]).tintColor = .red

in willConnectTo method of SceneDelegate

Answer 2

Update: posted this demo on GitHub - DemoWindowTint

The below demo is created on setting window's tintColor (which is inherited by all subviews) using the approach provided in How to access own window within SwiftUI view?.

In demo I used NavigationView with couple of NavigationLinks and Button showing Alert.

Tested with following

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)

            let contentView = ContentView()
                .environment(\.hostingWindow, { [weak window] in
                    return window })

            window.rootViewController = UIHostingController(rootView: contentView)

            self.window = window
    ...

struct ContentView: View {
    @Environment(\.hostingWindow) var hostingWindow
   ... // body can be any

    .onAppear {
            // can be loaded from UserDefaults here, and later changed on any action
            self.hostingWindow()?.tintColor = UIColor.red
    }