Show errors in Xamarin iOS WebView - xamarin

Question

The Xamarin Forms WebView control shows a white surface if connection fails. On iOS, I want to show any error information I can get.
I am using this code to override WkWebViewRenderer:
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/custom-renderer/hybridwebview
[assembly: ExportRenderer(typeof(HybridWebView), typeof(HybridWebViewRenderer))]
namespace CustomRenderer.iOS
{
public class HybridWebViewRenderer : WkWebViewRenderer, IWKScriptMessageHandler
{
public HybridWebViewRenderer() : this(new WKWebViewConfiguration())
{
}
}
}
I have also found this post which is now obsolete:
https://forums.xamarin.com/discussion/175060/how-can-i-display-a-detailed-error-code-retuned-from-a-webview?
How do I handle LoadFailed/Connection errors and display them to the user with WkWebViewRenderer?

Answer 1

For WkWebViewRenderer we need to implement the WKNavigationDelegate
public class HybridWebViewRenderer : WkWebViewRenderer, IWKScriptMessageHandler
{
public HybridWebViewRenderer()
{
}
protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
if(e.NewElement!=null)
{
this.NavigationDelegate = new NavigationDelegate();
}
}
public void DidReceiveScriptMessage(WKUserContentController userContentController, WKScriptMessage message)
{
throw new NotImplementedException();
}
}
public class NavigationDelegate : WKNavigationDelegate
{
public override void DecidePolicy(WKWebView webView, WKNavigationAction navigationAction, WKWebpagePreferences preferences, Action<WKNavigationActionPolicy, WKWebpagePreferences> decisionHandler)
{
// base.DecidePolicy(webView, navigationAction, preferences, decisionHandler);
decisionHandler.Invoke(WKNavigationActionPolicy.Allow, preferences);
}
public override void DidFailNavigation(WKWebView webView, WKNavigation navigation, NSError error)
{
base.DidFailNavigation(webView, navigation, error);
//...load fail
}
public override void DidFinishNavigation(WKWebView webView, WKNavigation navigation)
{
base.DidFinishNavigation(webView, navigation);
//...load success
}
}