Ios Swift&x2B；WKWebView：如何防止访问某些URL？

我有一个控制器，它有一个WKWebView实例。但是，我希望它不要加载任何请求到雅虎。它曾经与UIWebView一起使用（下面注释掉）。我不知道如何使用WKWebView来完成它

class WebBrowserViewController: UIViewController {

  let webView = WKWebView()

  override func loadView() {
    super.loadView()

    self.view = self.webView
  }

  override func viewDidLoad() {
    webView.navigationDelegate = self

    let url = NSURL(string: "https://www.google.com")!
    let request = NSURLRequest(URL: url)
    webView.loadRequest(request)
  }
}

extension WebBrowserViewController: WKNavigationDelegate {
  func webView(webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
    // this prints the right thing, but it doesn't allow me to stop the request
    print(webView.URL?.absoluteString)
  }
}

// WHAT I USED TO HAVE:

//extension WebBrowserViewController: UIWebViewDelegate {
//  func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
//    
//    if visitingYahoo(request.URL?.absoluteString) {
//      return false
//    } else {
//      return true
//    }
//  }
//}

我最终做到了：

extension WebBrowserViewController: WKNavigationDelegate {
  func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
    print(webView.URL?.absoluteString)
    if urlVideoType(webView.URL!) != VideoUrl.Unknown {
      loadVideo(webView.URL!)
      decisionHandler(.Cancel) //<------------------ this part
    }
    decisionHandler(.Allow) //<------------------ this part
  }
}

扩展Web浏览器服务控制器：WKNavigationDelegate{
func webView（webView:WKWebView，decisedpolicyfornavigationaction导航操作：WKNavigationAction，decisionHandler:（WKNavigationActionPolicy）->Void）{
打印（webView.URL？.absoluteString）
如果urlVideoType（webView.URL！）！=VideoUrl.Unknown{
loadVideo（webView.URL！）
decisionHandler（.Cancel）/我最终做到了：

extension WebBrowserViewController: WKNavigationDelegate {
  func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
    print(webView.URL?.absoluteString)
    if urlVideoType(webView.URL!) != VideoUrl.Unknown {
      loadVideo(webView.URL!)
      decisionHandler(.Cancel) //<------------------ this part
    }
    decisionHandler(.Allow) //<------------------ this part
  }
}

扩展Web浏览器服务控制器：WKNavigationDelegate{
func webView（webView:WKWebView，decisedpolicyfornavigationaction导航操作：WKNavigationAction，decisionHandler:（WKNavigationActionPolicy）->Void）{
打印（webView.URL？.absoluteString）
如果urlVideoType（webView.URL！）！=VideoUrl.Unknown{
loadVideo（webView.URL！）
decisionHandler（.Cancel）//如果url是网页的一部分，比如加载图像，该怎么办？如果url是网页的一部分，比如加载图像，该怎么办？