Keep a reference to UICollectionView header - ios

Question

I need to store a view to use as a UICollectionView header. I don't want it to cycle out of memory though, because it needs to keep its state/data, etc.
With a table view you can just do tableView.tableHeaderView = view.
Here's what I'm trying:
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
switch kind {
case MagazineLayout.SupplementaryViewKind.sectionHeader:
if let t = headerView { //headerView is an instance var
return t
} else {
let view = collectionView.dequeueReusableSupplementaryView(ofKind: MagazineLayout.SupplementaryViewKind.sectionHeader, withReuseIdentifier: "MyHeaderView", for: indexPath) as! MyHeaderView
view.titleLabel.text = "test"
view.switch.addAction(for: .valueChanged, { [weak self] in
self?.switchValueChanged()
})
headerView = view
return view
}
...
}
I don't want to re-create it every time the user scrolls it away and then back, so I'm trying to store a reference to it. This isn't working though. Hard to explain but the view it displays is cut off and the switch isn't responsive. If I comment out the "if" part and just create a new one every time, it looks correct but state is lost (i.e. the switch gets turned off) What's the best way to do this?

Answer 1

Since you're keeping the reference and not letting it deallocate when it scrolls out of the view, remove the register and dequeuing entirely. It worked fine for me, here's how:
let view = MyHeaderView()
override func viewDidLoad() {
super.viewDidLoad()
view.titleLabel.text = "test"
view.switch.addAction(for: .valueChanged, { [weak self] in
self?.switchValueChanged()
})
}
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
switch kind {
case MagazineLayout.SupplementaryViewKind.sectionHeader:
return view
//...
}
}