class ViewController: AZCollectionViewController {

    var lastIndex = 0
    var results = [String]()

    override func viewDidLoad() {
    
        nextLoadingCellNibName = "LoadingCollectionViewCell"
        nextLoadingCellIdentifier = "LoadingCollectionViewCell"
        loadNextPageLoaderCell(nibName: nextLoadingCellNibName, cellIdentifier: nextLoadingCellIdentifier) // Only if you want personal NextPage loading cell
        
        super.viewDidLoad()
        self.fetchData()

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
    
}

class ViewController: AZCollectionViewController {
    override func viewDidLoad() {

        self.loadLoadingView(nibName: "your nib name") // if bundle is nil
        self.loadErrorView(nibName: "your nib name", bundle: yourBundle) // if custom bundle

        super.viewDidLoad()
        self.fetchData()
    }
}

    self.loadLoadingView(nibName: "your nib name") // if bundle is nil

    self.loadLoadingView(nibName: "your nib name", bundle: yourBundle)

extension ViewController {

    override func AZCollectionView(_ collectionView: UICollectionView, cellForRowAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! TestCollectionViewCell
        
        cell.feedImage.image = UIImage(named: self.results[indexPath.row])
        
        return cell
    }
    
    override func AZCollectionView(_ collectionView: UICollectionView, heightForRowAt indexPath: IndexPath) -> CGSize {
    
        return CGSize(width: (collectionView.frame.size.width / 3) - 6, height: (collectionView.frame.size.width / 3) - 4)
        
    }
}

//MARK: - API Call
extension ViewController {
    
    override func fetchData() {
        super.fetchData()
        
        FakeService.getData { (error, results) in
           
            if let resu = results {
                self.results.removeAll()
                self.results.append(contentsOf: resu)
                self.didfetchData(resultCount: resu.count, haveMoreData: true)
            }
                
            else if let error = error {
                self.errorDidOccured(error: error)
            }
        }
    }
    
    override func fetchNextData() {
        super.fetchNextData()
        
        FakeService.getData (offset: results.count) { (error, results) in
            
            if let resu = results {
                
                self.results.append(contentsOf: resu)
                if self.results.count < 45 { // you probably get next page exist from service.
                    self.didfetchData(resultCount: resu.count, haveMoreData: true)
                }
                else {
                    self.didfetchData(resultCount: resu.count, haveMoreData: false)
                }
            }
            else if let error = error {
                self.errorDidOccured(error: error)
            }
        }
    }
}