Question

On iOS devices the section headers in UITableView’s have a nice behavior where they stick or ‘float’ to the top of the screen as you scroll through a section. The section headers in my particular case are loaded from other XIB files.

Is it possible to change the section headers depending on whether or not they are currently floating? Specifically I’d like to add a small shadow to appear under the header only while it’s stuck to the top of the view.

Thanks!

Answer 1

I haven’t tested it yet, but I don’t see any reason why it wouldn’t be possible.
Just make sure you set the right bounds (because your shadow needs to be on top of your view, not above it).

You can use the following approach:

1. Use scrollView:didScroll: to get notified about scroll-events.
2. In this method, check whether you need to add your shadow-view to your (floating) header-view.
3. If so, add it. (just [view addSubview:shadowView].) Something like CGRectMake(0.f, yourDefaultHeaderHeight, 320.f, yourShadowHeight) should be the frame of your shadowView.
4. Now, update the bounds of view, so it can show your shadowView: CGRectMake(0.f, 0.f - yourShadowHeight, 320.f, yourDefaultHeaderHeight + 2 * yourShadowHeight).
5. When you find out that your header isn’t floating anymore (by using scrollView:didScroll:), remove the shadow-view.

Your headerViews bounds should be 0.f - yourShadowHeight because if you use just 0.f, it’ll blur (I don’t know why …).