在 tableview 单元格内为 collectionview 加载更多功能

Question

I want to know how can I put load more functionality in collection view which is inside tableview cell. Since collection view scrolling is not enabled.

Putting a code of last index checking in collection view cell generating weird behaviour as some time reaching last index doesn't call functional at all and some time it load mores when moving to other cell. I know this is happening due to tableview cell. Can any one help me around how to fix it.

This is the code I am using:

//
//  JustForYouTableViewCell.swift
//  ShoppingPortal
//
//  Created by Faraz Haider on 10/07/2019.
//  Copyright © 2019 B2b. All rights reserved.
//

import UIKit
protocol JustForYouTableViewCellDelegate: class {
    func justForYouClickedWithItem(_ itemIndex:Int)
    func loadMoreDataForJustForYouWithPageNumber(pageNumber : Int, records: Int)
}


class JustForYouTableViewCell: BaseTableViewCell {

    @IBOutlet weak var justForYouCollectionView: UICollectionView!
    weak var delegate: JustForYouTableViewCellDelegate?
    var justForYouArray = [Product]()
    var cellHeight:CGFloat = 0
    var pageNumber = 1
    var currentRecordsCount = 0
    var totalNumberOfRecord = 0
    var isLoadMore = false
    var isReload = false

    @IBOutlet weak var collectionHeight: NSLayoutConstraint!
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }


    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }

    override func updateCell(rowModel: BaseRowModel) {
        if !isReload{
           justForYouArray = rowModel.rowValue as! [Product]
            pageNumber = rowModel.tag
            totalNumberOfRecord = rowModel.rowId
        }

        currentRecordsCount = justForYouArray.count

        if(currentRecordsCount < totalNumberOfRecord){
            isLoadMore = true
        }else{
            isLoadMore = false
        }
        self.delegate = rowModel.delegate as? JustForYouTableViewCellDelegate
        justForYouCollectionView.dataSource = self
        justForYouCollectionView.delegate = self
        justForYouCollectionView.isScrollEnabled = false
        cellHeight = rowModel.rowHeight

        NotificationCenter.default.addObserver(self, selector: #selector(doThisWhenNotify(notification:)), name: NSNotification.Name(rawValue: "post"), object: nil)

        self.collectionHeight.constant = self.justForYouCollectionView.collectionViewLayout.collectionViewContentSize.height;
        justForYouCollectionView.reloadData()
    }

    override func systemLayoutSizeFitting(_ targetSize: CGSize, withHorizontalFittingPriority horizontalFittingPriority: UILayoutPriority, verticalFittingPriority: UILayoutPriority) -> CGSize {

        self.layoutIfNeeded()
        let contentSize = self.justForYouCollectionView.collectionViewLayout.collectionViewContentSize
        return CGSize(width: contentSize.width, height: contentSize.height + 20) // 20 is the margin of the collectinview with top and bottom
    }


    @objc func doThisWhenNotify(notification : NSNotification) {
        if let info = notification.userInfo as? NSDictionary{
            if let id = info["product"] as? [Product]{
                justForYouArray.append(contentsOf:id)
            }
            isReload = true
            let homeVC = self.viewController as? HomeVC
            homeVC?.dashboardTblView.reloadData()

        }
    }

    @IBAction func moreButtonClicked(_ sender: Any) {

        let viewController:MoreProductsVC = UIStoryboard(name: "HomeModule", bundle: nil).instantiateViewController(withIdentifier: "MoreProductsVC") as! MoreProductsVC
        viewController.selectedState = .SelectedStateJustForYou
        self.viewController?.navigationController?.pushViewController(viewController, animated: true)
    }
}
extension JustForYouTableViewCell: UICollectionViewDataSource,UICollectionViewDelegate {

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return justForYouArray.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell : JustForYouCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "JustForYouCollectionViewCell", for: indexPath) as! JustForYouCollectionViewCell


        let deals = justForYouArray[indexPath.row]
        cell.titleLabel.text = Utility.checkEmptyString(deals.name)

        if deals.productImage.count>0{
            if let imageUrl = deals.productImage[0].url{
                let url = URL(string: imageUrl)
                let image = UIImage(named: "placeholder")
                cell.dealsImageView.kf.setImage(with: url, placeholder: image)
            }
        }

        if deals.setPriceOption == 1{
            cell.priceLabel.text = String(format: "%@ %d - %d %@", Utility.checkEmptyString(deals.fobPriceName),deals.min,deals.max,Utility.checkEmptyString(deals.tradeUnitName))
        }else{
            if deals.productDifferencePriceQuantity.count>0{
                cell.priceLabel.text = String(format: "%@ %d - %d %@", "USD",deals.productDifferencePriceQuantity[0].mOQ,deals.productDifferencePriceQuantity[0].fOBPrice,Utility.checkEmptyString(deals.tradeUnitTypeName))
            }else{
                cell.priceLabel.text = ""
            }

        }

        // Check if the last row number is the same as the last current data element
        if indexPath.row == self.justForYouArray.count - 1 && self.isLoadMore {
            updateNextSet()
        }

        return cell
    }

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        print(indexPath.row)
        let deals = justForYouArray[indexPath.row]
        let storyBoard: UIStoryboard = UIStoryboard(name: "HomeModule", bundle: nil)
        let newViewController = storyBoard.instantiateViewController(withIdentifier: "ProductDetailVC") as! ProductDetailVC
        if (deals.productId != nil){
            newViewController.selectedProductId = deals.productId
            self.viewController?.navigationController?.pushViewController(newViewController, animated: true)
        }

    }



    func updateNextSet(){
            pageNumber += 1
            self.delegate?.loadMoreDataForJustForYouWithPageNumber(pageNumber: pageNumber, records: currentRecordsCount)
            isLoadMore = false
    }
}


extension JustForYouTableViewCell: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let spacing : CGFloat = (collectionViewLayout as? UICollectionViewFlowLayout)?.minimumInteritemSpacing ?? 0.0
        let widthPerItem = (collectionView.frame.height  - spacing * 2) / 3
        return CGSize(width: screenWidth/2, height: 200)
    }
}

Answer 1

Ok I did get an answer from another source 😀 for people looking for the solution, what's I did is I put scroll view delegate scrollview did end dragging and in that I put condition of once you reach scroll view max height - height of my last cell I did load more over their. Thanks everyone

**

• code snippet

**

func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {

// UITableView only moves in one direction, y axis
let currentOffset = scrollView.contentOffset.y
let maximumOffset = scrollView.contentSize.height - scrollView.frame.size.height

// Change 10.0 to adjust the distance from bottom
if maximumOffset - currentOffset <= 235 {
    if (self.isLoadMore){
        self.isFirstTime = false
        justForYouPageNumber += 1
        callServiceFoNewArrivals(withPageNumber: justForYouPageNumber, andRecords: 10)
    }


   }
}