1 Xcode 11.3, swift 4.2 or above.
2 Implement UICollectionView and custom layout that displays folders and files.
3 Users can reorder an item by long tap on it, just implement UI, don’t need to reorder the real folders and files.
4 When the user drags a file over a folder, the folder zooms in, and the file will move into the folder if the tap gesture ends.
5 Smooth animations, flickering is not acceptable.