Drog.swift

class ViewController: UIViewController {
  func setupCollectionView() {
        self.collectionView.collectionViewLayout = columnLayout
        self.collectionView.dataSource = self
        self.collectionView.dragInteractionEnabled = true
        self.collectionView.dragDelegate = self
        self.collectionView.dropDelegate = self
    }
  
  func updateDataIndex(from fromIndexPath: IndexPath, to toIndexPath: IndexPath) {
        let fromPosition = fromIndexPath.item
        let toPosition = toIndexPath.item
        let selected = cellDataList[fromPosition] as Int
        DispatchQueue.main.async {[weak self] in
            self?.cellDataList.remove(at: fromPosition)
            self?.cellDataList.insert(selected, at: toPosition)
            self?.collectionView.reloadData()
            UIView.performWithoutAnimation {
                self?.collectionView.reloadSections(IndexSet(integersIn: 0...0))
            }
        }
    }
}

extension ViewController: UICollectionViewDropDelegate {
    func collectionView(_ collectionView: UICollectionView, performDropWith coordinator: UICollectionViewDropCoordinator) {
        if (collectionView.hasActiveDrag) {
            if let destinationIndexPath = coordinator.destinationIndexPath {
                updateDataIndex(from: coordinator.items.first!.sourceIndexPath!, to: destinationIndexPath)
            }
        }
    }

    func collectionView(_ collectionView: UICollectionView,
                        dropSessionDidUpdate session: UIDropSession,
                        withDestinationIndexPath destinationIndexPath: IndexPath?) -> UICollectionViewDropProposal {
        return UICollectionViewDropProposal(operation: .move, intent: .insertAtDestinationIndexPath)
    }
}