Weird animation when deleting item from UICollectionView while UIContextMenu is shown - ios

Question

I'm using UIContextMenuInteraction to show a context menu for UICollectionView as follows:
func collectiovnView(_ collectionView: UICollectionView, contextMenuConfigurationForItemAt indexPath: IndexPath, point: CGPoint) -> UIContextMenuConfiguration? {
return UIContextMenuConfiguration(identifier: nil, previewProvider: nil, actionProvider: { _ in
let deleteAction = UIAction(title: "Delete", image: UIImage(systemName: "trash"), attributes: .destructive) { _ in
self.deleteItem(at: indexPath)
}
return UIMenu(title: "Actions", children: [deleteAction])
})
}
func deleteItem(at indexPath: IndexPath) {
self.collectionView.performBatchUpdates({
self.items.remove(at: indexPath.item)
self.collectionView.deleteItems(at: [indexPath])
})
}
Everything works well, but when I tap the "Delete" item, a weird animation happens where the deleted item stays in its place while other items are moving, and then it disappears instantly. And sometimes I even see an empty space or a random item for fraction of a second before the new item appears.
If I call collectionView.deleteItems() while the context menu isn't shown the deletion animation works as expected.

Answer 1

It looks like the weird animation is a result of a conflict between two animations that run at almost the same time:
Deletion animation: When "Delete" item is tapped, collectionView.deleteItems() is called and the specified collection item is deleted with animation.
Menu dismiss animation: After the menu item is tapped, the context menu is also dismissed with another animation that shows the deleted item for a fraction of a second.
This looks like a bug that should be fixed by Apple. But as a workaround, I had to delay the deletion until the dismiss animation completed:
func deleteItem(at indexPath: IndexPath) {
let delay = 0.4 // Seconds
DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
self.collectionView.performBatchUpdates({
self.items.remove(at: indexPath.item)
self.collectionView.deleteItems(at: [indexPath])
})
}
}
The 0.4 seconds is the shortest delay that worked for me.