UICollectionView in UIControl - delegate & datasource - swift

Question

I've added a UICollectionView to a UIControl (which is being called in a UITableViewController section header) and the UICollectionView is appearing (background color shows), but the datasource and delegate seem to be ignored - no cells are showing and a print statement in my dequeueReusableCell function isn't being called (but one in the UIControl init method is. Can you tell me what I'm missing here?
My UIControl:
// Stripped down code
final class My_Control: UIControl {
override init(frame: CGRect) {
super.init(frame: frame)
addSubview(myCV)
}
private let myCV: Custom_CV = {
let cv: Custom_CV = Custom_CV()
return cv
}()
}
My Collection View:
final class Custom_CV: UIControl, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
override init(frame: CGRect) {
super.init(frame: frame)
addSubview(collectionView)
collectionView.dataSource = self
collectionView.delegate = self
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellIdentifier)
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell: UICollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath)
cell.backgroundColor = .red
print("Building cell") // Not being called
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 72.0, height: 72.0)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
//
}
private let cellIdentifier: String = "cellIdentifier"
private let collectionView: UICollectionView = {
let layout: UICollectionViewLayout = UICollectionViewLayout()
let collectionView: UICollectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
collectionView.backgroundColor = .white
return collectionView
}()
}
I think I'm missing something obvious, but I don't see it. I'm expecting to see 10 red squares and 10 print statements, but I get nothing there. But as I said - it's definitely being called because the a print statement in My_CV's init was being called, and I can see the .white background for the collectionview in My_Control.