UICollectionViewCell - contents do not animate alongside cell's contentView

Question

Problem looks like this: http://i.imgur.com/5iaAiGQ.mp4 (red is a color of cell.contentView)

Here is the code: https://github.com/nezhyborets/UICollectionViewContentsAni

Answer 1

You can apply a transform to a cell, although it has some drawbacks, such as handling orientation changes.

For extra impact, I have added a color change and a spring effect in the mix, neither of which could be achieved using the reloading route:

    func collectionView(_ collectionView: UICollectionView,
                        didSelectItemAt indexPath: IndexPath) {
        UIView.animate(
            withDuration: 0.4,
            delay: 0,
            usingSpringWithDamping: 0.4,
            initialSpringVelocity: 0,
            options: UIViewAnimationOptions.beginFromCurrentState,
            animations: {
                if( self.selectedIndexPath.row != NSNotFound) {
                    if let c0 =
                        collectionView.cellForItem(at: self.selectedIndexPath)
                    {
                        c0.contentView.layer.transform = CATransform3DIdentity
                        c0.contentView.backgroundColor = UIColor.lightGray
                    }
                }
                self.selectedIndexPath = indexPath
                if let c1 = collectionView.cellForItem(at: indexPath)
                {
                    c1.contentView.layer.transform =
                        CATransform3DMakeScale(1.25, 1.25, 1)
                    c1.contentView.backgroundColor = UIColor.red
                }

            },
            completion: nil)
    }