iOS tableview adapter custom code with pagination and refresh Control....

iOS-tableView-adapter.swift

import UIKit

protocol SSAdapterDelegate {
    func willDisplay(cell: UITableViewCell, indexPath: IndexPath)
    func didSelected(indexPath: IndexPath)
    func hasNextPage()->Bool
    func isLoadingFooterAdded()->Bool
    func loadMoreData()
    func refreshTableData()
}

extension SSAdapterDelegate{
    func loadMoreData(){}
    func didSelected(indexPath: IndexPath){}
    func hasNextPage()->Bool { return false }
    func refreshTableData(){}
}


class SSAdapter<T>: NSObject, UITableViewDelegate, UITableViewDataSource{
    var tv: UITableView
    var cellIdentifier: String
    var sDelegate: SSAdapterDelegate?
    var tableData:[T] = [T]()
    
    /* Refresh Control doesn't work properly on large title. To solve the issue set top constraint
     of tableView to the super view  */
    
    lazy var refresher: UIRefreshControl = {
        let refreshControl = UIRefreshControl()
        refreshControl.tintColor = UIColor(hexString: colorPrimary)
        refreshControl.addTarget(self, action: #selector(refreshContents), for: .valueChanged)
        return refreshControl
    }()
    
    init(tableView: UITableView,
         cellIdentifer: String,
         sDelegate: SSAdapterDelegate) {
        self.tv = tableView
        self.cellIdentifier = cellIdentifer
        self.sDelegate = sDelegate
        super.init()
        self.addRefreshControl()
    }
    
    func addRefreshControl(){
        if #available(iOS 10.0, *){
            self.tv.refreshControl = refresher
        }else{
            self.tv.addSubview(refresher)
        }
    }
    
    @objc func refreshContents(){
        sDelegate?.refreshTableData()
    }
    
    func isRefreshing()-> (Bool){
       return refresher.isRefreshing
    }
    
    func addLoadingFooter(){
        let spinner = UIActivityIndicatorView(style: .gray)
        spinner.startAnimating()
        spinner.frame = CGRect(x: CGFloat(0), y: CGFloat(0), width: tv.bounds.width, height: CGFloat(44))
        tv.tableFooterView = spinner
        tv.tableFooterView?.isHidden = false
    }
    
    func removeLoadingFooter(){
        tv.tableFooterView = nil
    }
    
    func addAll(itemList:[T]){
        tableData += itemList
        notifyDataSetChanged()
    }
    
    func addItem(item: T){
        tableData.append(item)
        let lastRow: Int = tv.numberOfRows(inSection: 0)
        let indexPath = IndexPath(row: lastRow, section: 0);
        tv.insertRows(at: [indexPath], with: .automatic)
    }
    
    func removeItem(position: Int){
        tableData.remove(at: position)
        let indexPath = IndexPath(row: position, section: 0);
        tv.deleteRows(at: [indexPath], with: .automatic)
    }
    
    func notifyDataSetChanged(){
        if refresher.isRefreshing{
            refresher.endRefreshing()
        }
        tv.reloadData()
    }
    
    ////////////////////////////////////////////////////////////////////////////
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return tableData.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) else { return UITableViewCell() }
        return cell
    }
    
    func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        sDelegate?.willDisplay(cell: cell, indexPath: indexPath)
        if (indexPath.row == tableData.count - 1 ){
            if  (sDelegate?.hasNextPage() ?? false) && !(sDelegate?.isLoadingFooterAdded() ?? false) {
                addLoadingFooter()
                sDelegate?.loadMoreData()
            }
        }
    }
    
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        sDelegate?.didSelected(indexPath: indexPath)
    }
}


extension UITableView {
    func setAdapter<T>(_ adapter: SSAdapter<T>) {
        dataSource = adapter
        delegate = adapter
        tableFooterView = UIView(frame: CGRect.zero)
        reloadData()
    }
}



/////////////////////////////////////////// HOW TO USE////////////////////////////////////////////////
class LockRequestViewController: BaseViewController {
    
    var presenter: LockRequestPresenterProtocol?
    
    @IBOutlet weak var tableView: UITableView!
    var lockRequests:[SingleLockRequest] = [SingleLockRequest]()
    var nextPageUrl: String?
    var isLoadingAdded: Bool = false
    var adapter: SSAdapter<SingleLockRequest>!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setupAddBarBtn() // Add a addLockRequest Bar button to the navigation Bar.........
    
        adapter = SSAdapter(tableView: tableView, cellIdentifer: LockRequestTableViewCell.className,  sDelegate: self)
        tableView.rowHeight = 70
        tableView.setAdapter(adapter)
        
        LockRequestAllWireFrame.createLockRequestsModule(view: self)
        presenter?.getLockRequestAll(url: APIs.GET_LOCK_REQUEST_ALL)
    }
    
    func setupAddBarBtn(){
        let addBtn = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addBtnDidTapped))
        self.navigationItem.rightBarButtonItem = addBtn
    }
    
    @objc func addBtnDidTapped(){
        performSegue(withIdentifier: "add_lock_request", sender: nil)
    }
    
    override func networkCallDidStarted(_ loadingMsg: String) {
        if !(isLoadingAdded || adapter.isRefreshing()){
            SVProgressHUD.show(withStatus: loadingMsg)
        }
    }
}


extension LockRequestViewController: LockRequestViewProtocol{
    
    func lockRequestDidReceived(lock: Locks) {
        if(adapter.isRefreshing()){
            self.lockRequests.removeAll()
            adapter.tableData.removeAll()
        }
        nextPageUrl = lock.nextPageURL
        lockRequests += lock.data
        adapter.addAll(itemList: lock.data)
        if(isLoadingAdded){
            isLoadingAdded = false
            adapter.removeLoadingFooter()
        }
    }
}


extension LockRequestViewController: SSAdapterDelegate {
    
    func isLoadingFooterAdded() -> Bool {
        return isLoadingAdded
    }
    
    func loadMoreData() {
        isLoadingAdded = true
        presenter?.getLockRequestAll(url: nextPageUrl!)
    }
    
    func refreshTableData() {
        presenter?.getLockRequestAll(url: APIs.GET_LOCK_REQUEST_ALL)
    }
    
    func hasNextPage() -> Bool {
        return nextPageUrl != nil
    }
    
    func willDisplay(cell: UITableViewCell, indexPath: IndexPath) {
        if (cell is LockRequestTableViewCell){
            let lockCell: LockRequestTableViewCell = cell as! LockRequestTableViewCell
            lockCell.configData(singleLockData: lockRequests[indexPath.row])
        }
    }
}