如何隐藏导航栏，当我的wkwebview开始滚动？

import UIKit
import WebKit

class ViewController: UIViewController, UIScrollViewDelegate {
    
    var webView: WKWebView!
    var navigationBar: UINavigationBar!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建WKWebView
        let webViewConfiguration = WKWebViewConfiguration()
        webView = WKWebView(frame: view.bounds, configuration: webViewConfiguration)
        webView.scrollView.delegate = self
        view.addSubview(webView)
        
        // 创建导航栏
        navigationBar = UINavigationBar(frame: CGRect(x: 0, y: 0, width: view.bounds.width, height: 44))
        view.addSubview(navigationBar)
        
        // 加载网页
        let url = URL(string: "https://www.example.com")
        let request = URLRequest(url: url!)
        webView.load(request)
    }
    
    // 检测滚动开始
    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
        // 隐藏导航栏动画
        UIView.animate(withDuration: 0.3) {
            self.navigationBar.alpha = 0
        }
    }
    
    // 检测滚动结束
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        // 显示导航栏动画
        UIView.animate(withDuration: 0.3) {
            self.navigationBar.alpha = 1
        }
    }
}