How can I make uiscrollview infinite in iOS?

Question

I want to scroll like that 1 2 3 1 2 3

I have some buttons suppose 10 which i want to show on endless scroll.

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Answer 1

The answers provided here are good but if you're still not satisfied and looking for a different approach here's what I've done.

The main idea is to update the number of cells whenever you reach the cell before the last one. Each time you increase the number of items by 1 so it gives the illusion of infinite scrolling. To do that we can utilize scrollViewDidEndDecelerating(_ scrollView: UIScrollView) function to detect when the user has finished scrolling, and then update the number of items in the collection view. Here's a code snippet to achieve that:

class InfiniteCarouselView: UICollectionView {

    var data: [Any] = []

    private var currentIndex: Int?
    private var currentMaxItemsCount: Int = 0
    // Set up data source and delegate
}

extension InfiniteCarouselView: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        // Set the current maximum to a number above the maximum count by 1
        currentMaxItemsCount = max(((currentIndex ?? 0) + 1), data.count) + 1
        return currentMaxItemsCount

    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
        let row = indexPath.row % data.count
        let item = data[row]
        // Setup cell
        return cell
    }
}

extension InfiniteCarouselView: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: collectionView.frame.height)
    }

    // Detect when the collection view has finished scrolling to increase the number of items in the collection view
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        // Get the current index. Note that the current index calculation will keep changing because the collection view is expanding its content size based on the number of items (currentMaxItemsCount)
        currentIndex = Int(scrollView.contentOffset.x/scrollView.contentSize.width * CGFloat(currentMaxItemsCount))
        // Reload the collection view to get the new number of items
        reloadData()
    }
}

Pros

• Straightforward implementation
• No use of Int.max (Which in my own opinion is not a good idea)
• No use of an arbitrary number (Like 50 or something else)
• No change or manipulation of the data
• No manual update of the content offset or any other scroll view attributes

Cons

• Paging should be enabled (Although the logic can be updated to support no paging)
• Need to maintain a reference for some attributes (current index, current maximum count)
• Need to reload the collection view on each scroll end (Not a big deal if the visible cells are minimal). This might affect you drastically if you're loading something asynchronously without caching (Which is a bad practice and data should be cached outside the cells)
• Doesn't work if you want infinite scroll in both directions