How to add pagination in UICollectionView in swift?

If you want to add bottom refresh control you have to use below helper class.

https://github.com/vlasov/CCBottomRefreshControl/tree/master/Classes

Download this 2 files which is in Objective-C. You have to import this file in Bridging header

#import "UIScrollView+BottomRefreshControl.h"

Add refresh control like this.

let refreshControl = UIRefreshControl.init(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
refreshControl.triggerVerticalOffset = 50.0 
refreshControl.addTarget(self, action: #selector(paginateMore), for: .valueChanged) 
collectionView.bottomRefreshControl = refreshControl

This helper class provide you new bottomRefreshControl property, which helps you to add refresh control in bottom.

Easy way to do that

 var page: Int = 0
 var isPageRefreshing:Bool = false

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    YourApi(page1: 0)
}

 func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if(self.mycollectionview.contentOffset.y >= (self.mycollectionview.contentSize.height - self.mycollectionview.bounds.size.height)) {
        if !isPageRefreshing {
            isPageRefreshing = true
            print(page)
            page = page + 1
            YourApi(page1: page)
        }
    }
}

In your api methods

func YourApi(page1: Int) {
    let mypage = String(page1)
    let request: String = String.init(format:"apiName/%@", mypage)
    print(request)
}

That's it.