webView — простейшее iOS приложение

import UIKit
import WebKit
class ViewController: UIViewController, WKNavigationDelegate {
    var webView: WKWebView!
    override func loadView() {
        webView = WKWebView()
        webView.navigationDelegate = self
        view = webView
    }
    override func viewDidLoad() {
        super.viewDidLoad()
        let url = URL(string: "http://example.com")!
        webView.load(URLRequest(url: url))
        let refresh = UIBarButtonItem(barButtonSystemItem: .refresh, target: webView, action: #selector(webView.reload))
        toolbarItems = [refresh]
        navigationController?.isToolbarHidden = false
    }
    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!){
        title = webView.title
    }
}