如何在UICollectionView上保持动画效果

func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    // 在cell即将显示时，添加动画效果
    cell.alpha = 0
    cell.transform = CGAffineTransform(scaleX: 0.5, y: 0.5)
    UIView.animate(withDuration: 0.5) {
        cell.alpha = 1
        cell.transform = CGAffineTransform.identity
    }
}

func collectionView(_ collectionView: UICollectionView, didEndDisplaying cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    // 在cell消失时，移除动画效果
    cell.alpha = 1
    cell.transform = CGAffineTransform.identity
}

collectionView.delegate = yourDelegateObject