Remove space between the cells of UICollectionView

Question

I have UICollectionViewCells that have only one UIImageView. I am using RxSwift for the project. The delegate is set in the Main.storyboard, and the datasource is set by the RxSwift. I need to remove the spaces between the cells, but having trouble with that. The methods from this thread are not working:

Aligning collection view cells to fit exactly 3 per row

I tried both answers but nothing happens.

Here is the UIViewCollectionControllers' code:

let disposeBag = DisposeBag()

override func viewDidLoad() {
    super.viewDidLoad()

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Register cell classes
    //self.collectionView!.register(UICollectionViewCell.self, forCellWithReuseIdentifier: reuseIdentifier)

    // Do any additional setup after loading the view.
    collectionView?.dataSource = nil
    setupCellConfiguration()
}

private func setupCellConfiguration() {
    //1
    immuneCells
        .bind(to: self.collectionView!
            .rx //2
            .items(cellIdentifier: CellTypeCollectionViewCell.Identifier,
                   cellType: CellTypeCollectionViewCell.self)) { // 3
                    row, cellType, cell in
                    cell.configureWithCellType(cellType: cellType) //4
        }
        .disposed(by: disposeBag) //5
}

override func numberOfSections(in collectionView: UICollectionView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}


override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of items
    let num = CellType.immune.count
    return num
}

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let screenWidth = UIScreen.main.bounds.width
    let scaleFactor = (screenWidth / 3) - 6

    return CGSize(width: scaleFactor, height: scaleFactor)
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    return UIEdgeInsets.zero
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return 0
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 0
}

Any suggestions would be greatly appreciated

Update

I tried setting up equal width and height, top, left constraints of UIImageView but it did not help.

This is how it looks:

Answer 1

Try

flowLayout.minimumLineSpacing = 0
flowLayout.minimumInteritemSpacing = 0