Infinite Scroll with UICollectionView in Swift

v.swift

import UIKit

class ViewController: UICollectionViewController, UICollectionViewDataSource, UICollectionViewDelegate {
    override func collectionView(collectionView: UICollectionView!, numberOfItemsInSection section: Int) -> Int {
        ...
    }
    
    override func collectionView(collectionView: UICollectionView!, cellForItemAtIndexPath indexPath: NSIndexPath!) -> UICollectionViewCell! {
        ...
    }

    override func scrollViewDidScroll(scrollView: UIScrollView) {
        let offsetY = scrollView.contentOffset.y
        let contentHeight = scrollView.contentSize.height
        if offsetY > contentHeight - scrollView.frame.size.height {
            loadSomeDataAndIncreaseDataLengthFunction()
            self.collectionView.reloadData()
        }
    }
}

As UICollectionView inherits UIScrollView, you can write delegate in UICollectionViewController class.

Not only use it for infinite scroll, you can prefetch images / data before they appear.

Infinite scroll doing with following link

https://webappcodes.com/infinite-scroll-in-collectionview-swift-programmatically