UICollectionViewController Footer/ Header not showing - ios

Question

I am implementing a one section UICollectionViewController where I would like to add a header & footer.
I have read RayWenderlich tutorial to implement the logic and everything works fine EXCEPT my header & footer which are not showing up.
I checked "Section Header" & "Section Footer" in storyboard inspector, and added identifier for each UICollectionReusableView with "headerView" and "footerView".
I implemented the viewForSupplementaryElementOfKind method (see below code), but is not triggered (no breakpoints fired while debugging) while referenceSizeForFooterInSection and referenceSizeForHeaderInSection are . When app launch, I can't see header and footer background color, however I can see a space which should be header & footer.
Thank you in advance!
Here is an extract from my ViewController:
class VoteNextCityViewController : UICollectionViewController, UICollectionViewDelegateFlowLayout {
fileprivate let sectionInsets = UIEdgeInsets(top: 50.0, left: 20.0, bottom: 50.0, right: 20.0)
fileprivate let itemsPerRow: CGFloat = 2
private let cellID = "cellID"
var pendingCityArray: [City] = []
override func viewDidLoad() {
super.viewDidLoad()
fetchVotedCities()
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath) as! VoteNextCityCell
let city = pendingCityArray[indexPath.row] //cannot not be nil, else numberOfItemsInSection would return 0
cell.setupView(city: city)
return cell
}
override func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return pendingCityArray.count
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
//2
let paddingSpace = sectionInsets.left * (itemsPerRow + 1)
let availableWidth = view.frame.width - paddingSpace
let widthPerItem = availableWidth / itemsPerRow
return CGSize(width: widthPerItem, height: widthPerItem+50)
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
insetForSectionAt section: Int) -> UIEdgeInsets {
return sectionInsets
}
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return sectionInsets.left
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
return CGSize(width: (self.collectionView?.frame.size.width)!, height: 50)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
return CGSize(width: (self.collectionView?.frame.size.width)!, height: 50)
}
func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
switch kind {
case UICollectionElementKindSectionFooter :
let view = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "footerView", for: indexPath as IndexPath)
view.backgroundColor = UIColor.blue
return view
case UICollectionElementKindSectionHeader:
let view = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "headerView", for: indexPath as IndexPath)
view.backgroundColor = UIColor.red
return view
default:
assert(false, "Unexpected element kind")
}
}

Answer 1

I think only the _ (underscore with a space) is missing as per new syntax.
So try replacing the function definition
func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
with the below one
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {