iOS UICollectionView with horizontal scrolling inside vertical UICollectionView cells reusing

Question

I have a performance issue when scrolling vertical collection cells with horizontal collection view in it. The reason is cell's data reusing - horizontal collection view reloading on every parent cell reuse cycle. Does anybody know how can I avoid such amount of reloads ?

var items: [ProductItem] {
  didSet {
    collectionView.reloadData()
  }
}

override func prepareForReuse() {
  super.prepareForReuse()

  items = nil
}

Answer 1

UICollectionView and UITableView use every cell again and again, that is how they work.

It you get your data from web ever time then cache them. You can use image-caching libraries.