Swift tableView Pagination

Question

I have success working tableview with json parsing codes.But may have 1000 more item so need pagination when scrolling bottom side. I dont know how can i do this my codes un

Answer 1

API handler is api handler for network call that just do POST and GET calls. getNotifications is basically just a post call with params( offset and pageSize ) and in response there is list. Main logic is changing offset depending on cell in willDisplay collectionView delegate. Comment if you having any question , happy to help.

var isFetching: Bool = false
var offset = 0
var totalListOnServerCount = 20 // it must be returned from server
var pageSize = 10 // get 10 objects for instance
// MARK: - API Handler
private func fetchNotifications(){
    // return from function if already fetching list
    guard !isFetching else {return}
        if offset == 0{
            // empty list for first call i.e offset = 0
            self.anyList.removeAll()
            self.collectionView.reloadData()
        }
        isFetching = true
        // API call to fetch notifications with given offset or page number depends on server logic just simple POST Call
        APIHandler.shared.getNotifications(offset: offset) {[weak self] (response, error) in
            if let response = response {
                self?.isFetching = false
                if self?.offset == 0{
                    // fetch response from server for first fetch
                    self?.notificationsResponse = response
                    if self?.refreshControl.isRefreshing ?? false {
                        self?.refreshControl.endRefreshing()
                    }
                }else{
                    // append if already exist ( pagination )
                    self?.notificationsResponse?.notifications.append(contentsOf: response.notifications)
                }
                self?.collectionView.reloadData()

            }

        }
}


// MARK: - Collection View Delegate
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {

    guard let anyList = responseFromServer else { return }
    // check if scroll reach last index available and keep fetching till our model list has all entries from server
    if indexPath.item == anyList.count - 1 && anyList.count  < totalListOnServerCount{

        offset += pageSize
        fetchNotifications()

    }
}