CollectionViewCells don't appear programmatically - Swift 5 - ios

Question

I want to show a collectionView that appears with animation after hitting a button.
The collectionView appears correctly but the collectionViewCells inside don't.
I have set the UICollectionViewDelegate and UICollectionViewDatasource methods correctly but they aren't called (tested with breakPoints).
I'm doing everything programmatically so I also had to register the SettingCell which is a common UICollectionViewCell to the respective cellID.
Also I thought there could be a problem since I was setting the delegate and datasource too late but I don't think so since they are set at the beginning in the init of the mother class.
class SettingsLauncer : NSObject, UICollectionViewDelegate, UICollectionViewDataSource{
var collectionView : UICollectionView = {
let layout = UICollectionViewLayout()
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.backgroundColor = .white
return cv
}()
let CelliD = "CelliD"
func handleMoreButton(){
//creating and adding View
if let windowView = UIApplication.shared.keyWindow {
let width = UIScreen.main.bounds.width
let height = UIScreen.main.bounds.height
let heightCollectionView = CGFloat(300)
let myHeight = height - heightCollectionView
collectionView.frame = CGRect(x: 0, y: height, width: width, height: 0)
UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseOut, animations: {
windowView.addSubview(self.collectionView)
self.collectionView.frame = CGRect(x: 0, y: myHeight, width: width, height: heightCollectionView)
}, completion: nil)
}
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CelliD, for: indexPath)
return cell
}
override init(){
super.init()
collectionView.register(SettingCell.self, forCellWithReuseIdentifier: CelliD)
collectionView.delegate = self
collectionView.delegate = self
}
}

Answer 1

please add these two lines in your init method
self.collectionView.delegate = self
self.collectionView.dataSource = yourDataSource
currently you are having
collectionView.delegate = self
collectionView.delegate = self
Also make your collectionView lazy ... and assign delgates there
private lazy var collectionView : UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.backgroundColor = .white
cv.delegate = self
cv.dataSource = yourDataSource
cv.translatesAutoresizingMaskIntoConstraints = false
return cv
}()