SwiftUI Change Status Bar Color with UIWindow

ContentView.swift

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

import SwiftUI

struct ContentView: View {
    
    @StateObject 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
            }
        }
        .prepareStatusBarConfigurator(statusBarConfigurator) // UIWindowの用意
        .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
    }
}

StatusBarConfigurator.swift

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

import UIKit
import SwiftUI

class StatusBarConfigurator: ObservableObject {
    
    private var window: UIWindow?
    
    var statusBarStyle: UIStatusBarStyle = .default {
        didSet {
            window?.rootViewController?.setNeedsStatusBarAppearanceUpdate()
        }
    }
    
    fileprivate func prepare(scene: UIWindowScene) {
        if window == nil {
            let window = UIWindow(windowScene: scene)
            let viewController = ViewController()
            viewController.configurator = self
            window.rootViewController = viewController
            window.frame = UIScreen.main.bounds
            window.alpha = 0
            self.window = window
        }
        window?.windowLevel = .statusBar
        window?.makeKeyAndVisible()
    }
    
    fileprivate class ViewController: UIViewController {
        weak var configurator: StatusBarConfigurator!
        override var preferredStatusBarStyle: UIStatusBarStyle { configurator.statusBarStyle }
    }
}

fileprivate struct SceneFinder: UIViewRepresentable {
    
    var getScene: ((UIWindowScene) -> ())?
    
    func makeUIView(context: Context) -> View { View() }
    func updateUIView(_ uiView: View, context: Context) { uiView.getScene = getScene }
    
    class View: UIView {
        var getScene: ((UIWindowScene) -> ())?
        override func didMoveToWindow() {
            if let scene = window?.windowScene {
                getScene?(scene)
            }
        }
    }
}

extension View {
    func prepareStatusBarConfigurator(_ configurator: StatusBarConfigurator) -> some View {
        return self.background(SceneFinder { scene in
            configurator.prepare(scene: scene)
        })
    }
}