SwiftUI Change Status Bar Color with Custom Hosting Controller

AppDelegate.swift

//
//  AppDelegate.swift
//  StatusBarTest
//
//  Created by hiroki on 2021/02/11.
//

import UIKit
import SwiftUI

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        let configuration = UISceneConfiguration()
        configuration.delegateClass = SceneDelegate.self
        return configuration
    }
}

class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    
    var window: UIWindow?

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        guard let scene = (scene as? UIWindowScene) else { return }
        window = UIWindow(windowScene: scene)
        window?.rootViewController = StatusBarConfigurator().hostingController(rootView: ContentView())
        window?.makeKeyAndVisible()
    }
}

class StatusBarConfigurator: ObservableObject {
    var statusBarStyle: UIStatusBarStyle = .default {
        didSet {
            _hostingController?.setNeedsStatusBarAppearanceUpdate()
        }
    }
    private var _hostingController: UIViewController?
    func hostingController<T: View>(rootView: T) -> UIViewController {
        let hc = HostingController(rootView: rootView.environmentObject(self))
        hc.configurator = self
        _hostingController = hc
        return hc
    }
    
    private class HostingController<T>: UIHostingController<T> where T: View {
        weak var configurator: StatusBarConfigurator!
        override var preferredStatusBarStyle: UIStatusBarStyle { configurator.statusBarStyle }
    }
}

ContentView.swift

//
//  ContentView.swift
//  StatusBarTest
//
//  Created by hiroki on 2021/02/11.
//

import SwiftUI

struct ContentView: View {
    
    @EnvironmentObject var statusBarConfigurator: StatusBarConfigurator
    
    var body: some View {
        VStack(spacing: 30) {
            Text("Status Bar Color Test")
                .font(.title)
            Button("Black") {
                statusBarConfigurator.statusBarStyle = .darkContent
            }
            Button("White") {
                statusBarConfigurator.statusBarStyle = .lightContent
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity) // 背景色をステータスバーまで広げるため
        .background(Color.gray.ignoresSafeArea()) // ステータスバーの色をわかりやすくするために背景をグレーに
    }
}