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POHow can I detect the completion of view layout for a UIWebView
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  1. POHow can I detect the completion of view layout for a UIWebView
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    copied!<p>I want to allow a user to associate a zoom factor with a document and use it as a starting point when displaying that document inside a UIWebView. It seems, however, that <code>webViewDidFinishLoad:</code> only indicates the end of in-memory loading, not including rendering or layout. Here's sample code to demonstrate the problem:</p> <pre><code>- (void)viewDidLoad { [super viewDidLoad]; UIWebView *webView = (UIWebView *)self.view; webView.delegate = self; webView.scalesPageToFit = YES; } - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; NSString *urlString = [[NSBundle mainBundle] pathForResource:@"Doc" ofType:@"pdf"]; NSURL *file = [NSURL fileURLWithPath:urlString]; [(UIWebView *)self.view loadRequest:[NSURLRequest requestWithURL:file]]; } - (void)webViewDidFinishLoad:(UIWebView *)webView { if (!webView.isLoading) { [webView.scrollView setZoomScale:1.5 animated:YES]; } } </code></pre> <p>The call to setZoomScale: executes with no effect (i.e. the file is displayed with a zoom factor of 1.0), apparently because it happens before the scroll view is in some state where it can deal with it. If I change the final method above to what follows, everything works as I'd hoped.</p> <pre><code>- (void)delayedZoomMethod { [((UIWebView *)self.view).scrollView setZoomScale:1.5 animated:YES]; } - (void)webViewDidFinishLoad:(UIWebView *)webView { [self performSelector:@selector(delayedZoomMethod) withObject:nil afterDelay:1.0]; } </code></pre> <p>This, of course, is a bad idea because the 1.0 delay is arbitrary, probably too long for the vast majority of cases, and will likely be too short under some unknown set of conditions.</p> <p>The docs say, "<em>Your application can access the scroll view if it wants to customize the scrolling behavior of the web view.</em>" Does anyone know of a notification, or property in the web view or its scroll view, that I could observe to be told <strong>when</strong> that statement becomes true?</p>
 

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