UIWebView didFinishLoading fires multiple times

Question

I have some code that needs to run after the a UIWebView finishes loading a document. For that I've set the UIWebView's delegate to my controller, and implemented the webViewDidFinishLoading method.

This gets called multiple times, depending on the type of page to load. I'm not sure if it's because of ajax requests, requests for images, or maybe even iframes.

Is there a way to tell that the main request has finished, meaning the HTML is completely loaded?

Or perhaps delay my code from firing until all of those events are done firing?

Answer 1

You could check the loading and request properties in the webViewDidFinishLoad method

Answer 2

You can do something like this to check when loading is finished. Because you can have a lot of content on the same page you need it.

- (void)webViewDidFinishLoad:(UIWebView *)webview  {
    if (webview.loading)
        return;
    // dow some work
}

Answer 3

It could be enlightening (if you haven't gone this far yet) to NSLog a trace of load starts and finishes.

    - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
       NSLog(@"Loading: %@", [request URL]);
    }


    - (void)webViewDidFinishLoad:(UIWebView *)webView {
       NSLog(@"didFinish: %@; stillLoading:%@", [[webView request]URL],
            (webView.loading?@"NO":@"YES"));
    }


    - (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
       NSLog(@"didFail: %@; stillLoading:%@", [[webView request]URL],
            (webView.loading?@"NO":@"YES"));
    }

I just watched the calls to all three in one of my projects which loads a help page from my bundle and contains embedded resources (external css, YUI!, images). The only request that comes through is the initial page load, shouldStartLoadWithRequest isn't called for any of the dependencies. So it is curious why your didFinishLoad is called multiple times.

Perhaps what you're seeing is due to redirects, or as mentioned, ajax calls within a loaded page. But you at least should be able balance calls to shouldStartLoad and either of the other two delegate functions and be able to determine when the loading is finished.