Android Question WebView error 404 source html body

What did you expect? the image does not exists... Error 404.

here is project

it's teletext and I want to avoid blank screen, to detect if site or in this case gif not exist

There's a java solution on this page: http://twigstechtips.blogspot.co.uk/2013/01/android-override-default-webview-error.html.
You need to set a WebViewClient and override the WebViewClient's onReceiveError callback.

B4A's WebView has a WebViewClient set but it does not override the onReceiveError callback.

My WebViewExtras2 library allows you to set a WebViewClient that overrides the onReceiveError callback.
When an error occurs it raises the event:

ReceivedError (ErrorCode As Int, Description As String, FailingUrl As String)

So you can listen for that event, look at the error code and display a custom error page.

WebViewExtras2 can be downloaded from here: http://b4a.martinpearman.co.uk/webviewextras/WebViewExtras2-v2.10.zip

And a forum search for ReceivedError shows some results that may be useful.

The simplest way is to use HttpUtils2 and check whether the request is successful or not.