SwiftUI Webview with a Progress Bar

Webview.swift

import SwiftUI
import WebKit

struct ContentView: View {
	var body: some View {
		Webview(url: URL(string: "https://google.com")!)
	}
}

struct Webview: UIViewControllerRepresentable {
	let url: URL

	func makeUIViewController(context: Context) -> WebviewController {
		let webviewController = WebviewController()

		let request = URLRequest(url: self.url, cachePolicy: .returnCacheDataElseLoad)
		webviewController.webview.load(request)

		return webviewController
	}

	func updateUIViewController(_ webviewController: WebviewController, context: Context) {
		let request = URLRequest(url: self.url, cachePolicy: .returnCacheDataElseLoad)
		webviewController.webview.load(request)
	}
}

class WebviewController: UIViewController {
	lazy var webview: WKWebView = WKWebView()
	lazy var progressbar: UIProgressView = UIProgressView()

	override func viewDidLoad() {
		super.viewDidLoad()

		self.webview.frame = self.view.frame
		self.view.addSubview(self.webview)

		self.view.addSubview(self.progressbar)
		self.progressbar.translatesAutoresizingMaskIntoConstraints = false
		self.view.addConstraints([
			self.progressbar.topAnchor.constraint(equalTo: self.view.topAnchor),
			self.progressbar.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
			self.progressbar.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
		])

		self.progressbar.progress = 0.1
		webview.addObserver(self, forKeyPath: "estimatedProgress", options: .new, context: nil)
	}

	// MARK: - Web view progress
	override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
		switch keyPath {
		case "estimatedProgress":
			if self.webview.estimatedProgress >= 1.0 {
				UIView.animate(withDuration: 0.3, animations: { () in
					self.progressbar.alpha = 0.0
				}, completion: { finished in
					self.progressbar.setProgress(0.0, animated: false)
				})
			} else {
				self.progressbar.isHidden = false
				self.progressbar.alpha = 1.0
				progressbar.setProgress(Float(self.webview.estimatedProgress), animated: true)
			}
		default:
			super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
		}
	}
}