UICollectionViewCell could not dequeue a view of kind : UICollectionElementKindCell with identifier - swift

Question

I am following Duc Tran's Tutorial on a collection (https://www.youtube.com/watch?v=vB-HKnhOgl8) and when I am running my application, I keep getting this error:
Thread 1: Exception: "could not dequeue a view of kind: UICollectionElementKindCell with identifier CHALLENGECELL - must register a nib or a class for the identifier or connect a prototype cell in a storyboard"
I looked at other solutions for this but none have yielded results.
Here is the code for the view controller that holds the collection
import UIKit
class ChallengesViewerViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
//MARK: - UICollectionViewDataSource
private var challenges = WeeklyChallenges.createChallenge()
let cellScaling: CGFloat = 1.0
override func viewDidLoad() {
super.viewDidLoad()
let screenSize = UIScreen.main.bounds
let cellWidth = floor(screenSize.width * cellScaling)
let cellHeight = floor(screenSize.height * cellScaling)
let insetX = (view.bounds.width - cellWidth)/2
let insetY = (view.bounds.height - cellHeight)/2
let layout = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
layout.itemSize = CGSize(width: cellWidth, height: cellHeight)
collectionView.contentInset = UIEdgeInsets(top: insetY, left: insetX, bottom: insetY, right: insetX)
collectionView.dataSource = self
}
}
extension ChallengesViewerViewController: UICollectionViewDataSource{
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return challenges.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CHALLENGECELL", for: indexPath) as! ChallengeCollectionViewCell
cell.challenge = self.challenges[indexPath.item]
return cell
}
}
Additionally, here is the storyboard where I am assigning the reusable identifier to the collection view cell.

Answer 1

You have to register the cell that you're dequeuing in cellForItem in viewDidLoad.
override func viewDidLoad() {
super.viewDidLoad()
//...
collectionView.register(ChallengeCollectionViewCell.self, forCellWithReuseIdentifier: "CHALLENGECELL")
}
If you're using Nib use this instead:
let nib = UINib(nibName: <#T##String#>, bundle: nil)
collectionView.register(nib, forCellWithReuseIdentifier: "CHALLENGECELL")