Question about loading collectionView cell repeatedly in Swift - ios

Question

I want to load collectionView Cell repeatedly.
I want to make a dynamic cell, and when 20 cells are loaded, I want to make 40 cells by loading 20 underneath again.
API.requestBookCategory(bookCategory: 9, bookAddPoint: 0, completionHandler: handleBooksCategory(books:error:))
func handleBooksCategory(books: Books?, error: Error?) {
self.booksCategory = books
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
This code retrieves information from 20 books in bookCategory 9.
When importing 1 to 20 book information, insert bookAddPoint 0.
After that, we insert book information into the bookCatagory variable and use bookCategory to display the book information data in the cell.
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return booksCategory?.books.count ?? 0
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView
.dequeueReusableCell(withReuseIdentifier: "MainBookCell", for: indexPath) as! MainBookCell
func handleImageResponse() {
guard let imageURL = URL(string: booksCategory?.books[indexPath.row].bookImage ?? "") else {
return
}
API.requestImageFile(url: imageURL, completionHandler: handleImageFileResponse(image:error:))
}
func handleImageFileResponse(image: UIImage?, error: Error?) {
DispatchQueue.main.async {
cell.bookImageView.image = image
}
}
cell.bookTitleLabel.text = booksCategory?.books[indexPath.row].bookTitle
cell.bookWriterLabel.text = booksCategory?.books[indexPath.row].authorName
handleImageResponse()
return cell
}
}
I go through the process up to here, and a cell displaying 20 book information is created.
If a cell showing the 20th book information is created,
API.requestBookCategory (bookCategory: 9, bookAddPoint: 20, completionHandler: handleBooksCategory (books: error :))
I want to run a code that modifies bookAddPoint from 0 to 20, like the code above, to create a cell that displays the 21st to 40th book information. What should I do?

Answer 1

in viewControoller create a variables
var bookAddPoint = 0
var pageLength = 20
func callNextPageData(){
bookAddPoint = booksCategory?.books.count + 1
API.requestBookCategory(bookCategory: 9, bookAddPoint: bookAddPoint, completionHandler: handleBooksCategory(books:error:))
}
change
func handleBooksCategory(books: Books?, error: Error?) {
for book in books{
self.booksCategory.appen(book)
}
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
Change cellforItem
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView
.dequeueReusableCell(withReuseIdentifier: "MainBookCell", for: indexPath) as! MainBookCell
func handleImageResponse() {
guard let imageURL = URL(string: booksCategory?.books[indexPath.row].bookImage ?? "") else {
return
}
API.requestImageFile(url: imageURL, completionHandler: handleImageFileResponse(image:error:))
}
func handleImageFileResponse(image: UIImage?, error: Error?) {
DispatchQueue.main.async {
cell.bookImageView.image = image
}
}
cell.bookTitleLabel.text = booksCategory?.books[indexPath.row].bookTitle
cell.bookWriterLabel.text = booksCategory?.books[indexPath.row].authorName
handleImageResponse()
if indexPath.row == self.booksCategory.count-3 // it will load records before you reach end point automatically you can increase or decrease number
{
callNextPageData()
}
return cell
}
NOTE: if you want to do this on load more button just call callNextPageData() in button action or in tableView footer actions.