Mimic behaviour of UITableView section headers staying visible during scroll

When you have a sectioned, plain-style tableview on the iPhone, such as in the Contacts app, the section headers remain visible when you scroll past them until they are pushed offscreen by the next section header.

Does anyone know how to achieve something l开发者_开发百科ike this in an ordinary scrollview? I already have one scrollview nested in another to get horizontal paging with vertical smooth-scrolling, so I'm reluctant to add a third scrollview.

Cheers

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Basically I did a bunch of maths in scrollViewDidScroll: and set the frame of the subview.

Edit:

Well my exact requirements were a bit different than the question I asked, I have a footer view as opposed to a header view. Basically in scrollViewDidScroll I have:

CGRect frame = self.footerView.frame;
frame.origin.y = MIN(self.bounds.size.height -
                     self.footerView.frame.size.height +
                     self.contentOffset.y,
                     self.contentSize.height);
self.footerView.frame = frame;

This ensures the footer view, which is a subview of the scroll view, is always visible at the bottom of the scroll view, and there is never a gap between the footer view and the bottom of the content view.