Question

I am using a UIWebView to show a PDF. I need to track some UIScrollView events, so I set the built-in UIScrollView like this:

for(UIScrollView *s in webView.subviews) {

    s.delegate = self;

}

But the problem is that when I do this, I lose the ability to pinch to zoom (like I could before because the UIWebView’s Scale Pages to Fit property was set). How come this happens? What can I do to fix it? I went ahead and implemented the UIScrollView shouldZoom method, but when I pass back the scrollView as the view to zoom on, it zooms from the corner, not where my fingers are.

Does anybody know a solution to this problem? How can I have the UIScrollView delegate set, and still retain natural zooming ability?

Thanks!

Answer 1

Either handle the following events in your delegate:

– viewForZoomingInScrollView:
– scrollViewWillBeginZooming:withView:
– scrollViewDidEndZooming:withView:atScale:
– scrollViewDidZoom:

or save the original delegate

origDelegate = s.delegate;
s.delegate = self;

and forward the calls, e.g:

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return [origDelegate viewForZoomingInScrollView:scrollView]; 
}