dynamic collectionView in TableView - ios

Question

I have a dynamic collectionView in TableView and there are three errors:
the cells are not displayed correctly when the application starts
when I do inserItem the cells flicker as if they are rebooting
and most importantly when collectionView.insertItems the first four cells are hidden, the video
thanks
MainViewController
class ViewController: UIViewController, UIScrollViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
setting()
}
func setting(){
getData()
tableView.dataSource = self
tableView.delegate = self
tableView.estimatedRowHeight = UITableView.automaticDimension
tableView.rowHeight = UITableView.automaticDimension
}
//load data
func pagination(_ completion: (()->())?){
SmartNetworkSevrice.getGoods(with: url) { [unowned self] (data) in
guard data.modals.count > 0 else {
self.tableView.tableFooterView = nil
return
}
self.goods.append(contentsOf: data.modals)
self.offSet += data.modals.count
DispatchQueue.main.async {
let indexPath = IndexPath(row: 0, section: 0)
self.tableView.tableFooterView = nil
if self.goods.count == data.modals.count || self.isRefresh {
self.tableView.reloadRows(at: [indexPath], with: .none)
} else {
if let cell = self.tableView.cellForRow(at: indexPath) as? TVCellGoods {
UIView.performWithoutAnimation {
self.tableView.beginUpdates()
cell.insertGoods(data.modals)
cell.layoutIfNeeded()
cell.collectionViewHeight.constant = cell.collectionView.collectionViewLayout.collectionViewContentSize.height
self.tableView.endUpdates()
}
}
}
completion?()
}
}
// define bottom of tableView
func scrollViewDidScroll(_ scrollView: UIScrollView) {
guard scrollView == self.tableView else { return }
if (!isMoreDataLoading) {
// Вычислить позицию длины экрана до нижней части результатов
let scrollViewContentHeight = scrollView.contentSize.height
let scrollOffsetThreshold = scrollViewContentHeight - scrollView.bounds.size.height
if(scrollView.contentOffset.y > scrollOffsetThreshold && scrollView.isDragging) {
isMoreDataLoading = true
self.tableView.isScrollEnabled = false;
self.tableView.isScrollEnabled = true;
pagination(nil)
}
}
}
}
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: "goods", for: indexPath) as? TVCellGoods else { return UITableViewCell() }
guard bestGoods.count != 0, goods.count != 0 else { return UITableViewCell() }
cell.delegate = self
cell.configure(bestGoods, goods, categories)
// автообновление высоты
self.tableView.beginUpdates()
cell.collectionViewHeight.constant = cell.collectionView.collectionViewLayout.collectionViewContentSize.height
self.tableView.endUpdates()
return cell
}
}
extension ViewController: UITableViewDelegate, CallDelegate {
func callMethod() {}
func callMethod(push vc:UIViewController) {
self.navigationController?.pushViewController(vc, animated: true)
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableView.automaticDimension
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableView.automaticDimension
}
}
TableViewCell with collectionView
class TVCellGoods: UITableViewCell {
#IBOutlet weak var collectionView:UICollectionView!
#IBOutlet weak var collectionViewHeight:NSLayoutConstraint!
weak var delegate:CallDelegate?
var bestGoods = [Goods]() // лучшие товары
var goods = [Goods]() // все товары
var categories = [Menu]()
override func awakeFromNib() {
super.awakeFromNib()
collectionView.delegate = self
collectionView.dataSource = self
collectionView.tag = 2
collectionView.isScrollEnabled = false
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
func configure(_ best:[Goods],_ goods:[Goods], _ category:[Menu]) {
self.bestGoods = best
self.goods = goods
self.categories = category
self.collectionView.reloadData()
}
func insertGoods(_ data:[Goods]) {
self.goods.append(contentsOf: data)
let count = self.bestGoods.count + self.categories.count + self.goods.count
let indexPaths = ((count - data.count) ..< count)
.map { IndexPath(row: $0, section: 0) }
self.collectionView.performBatchUpdates({
self.collectionView.insertItems(at: indexPaths)
}, completion: nil)
}
}
and CollectionViewCell
class CVCellGoods: UICollectionViewCell {
#IBOutlet weak var bgView: UIView!
#IBOutlet weak var imageView: UIImageView!
#IBOutlet weak var title: UILabel!
#IBOutlet weak var price: UILabel!
#IBOutlet weak var delivery: UIImageView!
#IBOutlet weak var premium: UIImageView!
override func prepareForReuse() {
super.prepareForReuse()
delivery.image = nil
premium.image = nil
title.text = nil
price.text = nil
imageView.image = nil
imageView.sd_cancelCurrentImageLoad()
}
override func awakeFromNib() {
super.awakeFromNib()
imageView.backgroundColor = UIColor(red: 215/255, green: 215/255, blue: 215/255, alpha: 1)
self.contentView.layer.cornerRadius = 5
self.contentView.layer.masksToBounds = true
self.layer.shadowColor = UIColor.black.cgColor
self.layer.shadowOffset = CGSize(width: 0, height: 0.5)
self.layer.shadowRadius = 1
self.layer.shadowOpacity = 0.3
self.layer.masksToBounds = false
self.layer.shouldRasterize = true
self.layer.rasterizationScale = UIScreen.main.scale
}
}
EDIT: this gives a small bug at startup
TVCellGoods.swift
override func layoutSubviews() {
super.layoutSubviews()
self.collectionView.collectionViewLayout.invalidateLayout()
}

Answer 1

I just figured out how to solve your problem.
You gonna have to invalidate your collection view layout, as you are using an collectionView inside a tableView just add the following method on TVCellGoods.swift
override func layoutSubviews() {
super.layoutSubviews()
self.collectionView.collectionViewLayout.invalidateLayout()
}
I tested it, and worked!!
see video

Answer 2

It's not a good idea to add a scroll view inside another scroll view!
Do you have an example project in order to help you?

Answer 3

the cells are not displayed correctly when the application starts
You calculate collectionView itemSize in ViewDidLoad,
but in ViewDidLoad TableView & TableviewCell width not equal ViewController.
override func viewDidLoad() {
super.viewDidLoad()
print(view.frame.size.width) //320
print(tableView.frame.size.width) //414
}
You can try reloadData in ViewDidAppear.
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print(view.frame.size.width) //320
print(tableView.frame.size.width) //320
tableView.reloadData()
}
when collectionView.insertItems the first four cells are hidden
Subclass UICollectionViewFlowLayout
class MyCollectionViewFlowLayout: UICollectionViewFlowLayout {
override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
return true
}
}
TVCellGoods.swift
override func awakeFromNib() {
super.awakeFromNib()
collectionView.delegate = self
collectionView.dataSource = self
collectionView.tag = 2
collectionView.isScrollEnabled = false
collectionView.collectionViewLayout = MyCollectionViewFlowLayout()
}