CollectionView: HeaderView Bounce - swift

Question

pretty new to CollectionView so hope to have a direction here.
I have a CollectionView with an header enabled. All works fine but I want the HeaderView stay still while scrolling the main section.
Question:
Is that possible in iOS given a collectionview? Or I have to create a dedicated still view for the header?
I set the below in the UICollectionViewFlowLayout
if let layout: UICollectionViewFlowLayout = self.collectionViewLayout as? UICollectionViewFlowLayout {
layout.scrollDirection = .vertical
layout.sectionHeadersPinToVisibleBounds = true
}
which makes the header behave as below:
When scrolling down the main collection, the header goes up until it's lower margin reaches the top of the screen, then bunches in the middle of the sceen
When going up the header follows the main collection and become hided
I am pretty sure I am not the only one which has had this issue. Maybe I am doing something wrong here?

Answer 1

layout.sectionHeadersPinToVisibleBounds = true
that makes your header:
stick to the cells, when you scroll down
begin to hide after bottom of cells reaches bottom of the header
I see that you want the header to be still at all times. Of course, as you said, you could add a UIView on top of the collectionView, which would do the job. A different solution may be this:
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "header", for: indexPath)
headerContainer.backgroundColor = .yellow
headerContainer.frame = header.frame
header.layer.masksToBounds = false // that's important
header.addSubview(self.headerContainer)
return header
}
So basically, we're adding a subview inside our header (header needs to be transparent then). Now, we're using the fact that UICollectionView is scrollable:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let offset = scrollView.contentOffset.y
if offset < 0 {
headerContainer.transform = CGAffineTransform(translationX: 0, y: offset)
}
}
So if we are scrolling down by offset value, we transform the container by adding offset value to its Y position.
Unfortunately, I haven't come up with the case of scrolling up (it still begins to hide after some time) - I guess it's doable.
I based on this topic:
TableView header bouncing
I think I'd rather make a UIView outside of UICollectionView anyway.