UIWebView - How to identify the "last" webViewDidFinishLoad message?

Question

The webViewDidFinishLoad message seems to be sent each time any object in the page has been loaded. Is there a way to determine that all loading of content is done?

Answer 1

I'm guessing that iframes cause the webViewDidStartLoad / webViewDidFinishLoad pair.

The [webView isLoading] check mentioned as an answer didn't work for me; it returned false even after the first of two webViewDidFinishLoad calls. Instead, I keep track of the loading as follows:

- (void)webViewDidStartLoad:(UIWebView *)webView {
  webViewLoads_++;
}


- (void)webViewDidFinishLoad:(UIWebView *)webView {
  webViewLoads_--;

  if (webViewLoads_ > 0) {
    return;
  }

  …
}

- (void)webView:(UIWebView*)webView didFailLoadWithError:(NSError*)error {
  webViewLoads_--;
}

(Note this will only work if the start / finished pairs don't come serially, but in my experience so far that hasn't happened.)

Answer 2

Check this one, it will definitely work for you:

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    if ([[webView stringByEvaluatingJavaScriptFromString:@"document.readyState"] isEqualToString:@"complete"]) {
        // UIWebView object has fully loaded.
    }
}

Answer 3

Interesting, I wouldn't have thought it would work like that. Although I'm sure there are other ways to do it (is there a way to extract the URL from the webViewDidFinishLoad message so that you can see which one is the main page finishing loading?), the main thing I can think of is using the estimatedProgress to check the progress of the page and fire off whatever you want to do when it's 100% finished loading, which is what I do in my app. Google "iphone webview estimatedprogress" and click the first link for a guide I wrote on how to do this.

Update:

Please use phopkins' answer below instead of mine! Using private APIs in your apps is a bad idea and you will probably get rejected, and his solution is the right one.

Answer 4

Another way to monitor load progress with less control is to observe the WebViewProgressEstimateChangedNotification, WebViewProgressFinishedNotification, and WebViewProgressStartedNotification notifications. For example, you could observe these notifications to implement a simple progress indicator in your application. You update the progress indicator by invoking the estimatedProgress method to get an estimate of the amount of content that is currently loaded.

from http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/WebKit/Classes/WebView_Class/Reference/Reference.html

Answer 5

You can also use this short Category I wrote that adds blocks into UIWebView and also lets you choose between default UIWebView behavior (getting notified after each object load), or the "expected" behavior (getting notified only when the page has fully loaded).

https://github.com/freak4pc/UIWebView-Blocks

Answer 6

I needed to capture a variable from the page which was not fully loaded yet.

This worked for me:

- (void) webViewDidFinishLoad:(UIWebView *)webView {
    NSString *valueID = [webView stringByEvaluatingJavaScriptFromString:@"document.valueID;"];

    if([valueID isEqualToString:@""]){
        [webView reload];
        return;
    }

    //page loaded
}

Answer 7

All of the options did not really work for my use case. I used phopkins example slightly modified. I found that if the HTML loaded into the webview contained an image that would be a separate request that happened serially so we have to account for that and I did that with a timer. Not the best solution but it seems to work.:

- (void)webViewActuallyFinished {
     _webViewLoads--;

    if (_webViewLoads > 0) {
        return;
    }

    //Actually done loading

}

- (void)webViewDidStartLoad:(UIWebView *)webView {
    _webViewLoads++;
}


- (void)webViewDidFinishLoad:(UIWebView *)webView {


    [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(webViewActuallyFinished) userInfo:nil repeats:NO];
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
  _webViewLoads--;
}

Answer 8

hi it may be a bit far back already but i hope this helps.

i just used a notification when it enters the webViewDidFinishLoad method so that i can capture one instance of the method and then i'll detect the notification and do my logic from there.

hope this helps. it does not capture the last called instance of the webViewDidFinishLoad method, but allows you to do something once it has been called and not be repeated calls to that particular method (eg. showing a button) too.

*********EDIT*********

i did a test and managed to test it out. it actually works and the method called from the notification will be called after the full page has been loaded.

alternatively, i think you can do a counter on the delegate method webViewDidStartLoad and also on webViewDidFinishLoad to make sure that they are the same before you run your codes. this though, is an ugly hack as we will never know how many times it will be called unless like me, you are loading a html feed and can add a JavaScript to check how many elements there are on the page that you are loading. i'm just sharing some of the methods i have tried to solve this. hope it helps.

feedback is encouraged. thanks!

Answer 9

Here's what I use to show a spinner while DOM loads, built on top of @Vinod's answer.

Note that between webViewDidStartLoad and webViewDidFinishLoad the readyState is completed from the previous request (if any), that's why the polling should begin after webViewDidFinishLoad.

readyState possible values are loading, interactive or completed (and maybe nil ?)

- (void)webViewDidStartLoad:(UIWebView *)webView {
    [self spinnerOn];
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    [self startDOMCompletionPolling];
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
    [self startDOMCompletionPolling];
}


- (void)startDOMCompletionPolling {
    if (self.domCompletionListener) {
        [self.domCompletionListener invalidate];
    }
    self.domCompletionListener = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(checkDOMCompletion) userInfo:nil repeats:YES];
}

- (void)checkDOMCompletion {
    NSString *readyState = [self.webView stringByEvaluatingJavaScriptFromString:@"document.readyState"];

    if (readyState != nil) {
        if (readyState.length > 0) {
            if ([readyState isEqualToString:@"loading"]) { //keep polling
                return;
            }
        }
    }
    //'completed', 'interactive', nil, others -> hide spinner
    [self.domCompletionListener invalidate];
    [self spinnerOff];
}

Answer 10

The way I do it is this:

- (void)webViewDidFinishLoad:(UIWebView *)webview  {
    if (webview.loading)
    return;
    // now really done loading code goes next
    [logic]
}