Question

我想重复加载collectionView Cell。

我想制作一个动态单元格，当加载20个单元格时，我想通过再次在下面填充20个单元格来制作40个单元格。

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()
        }
    }

此代码从bookCategory 9中的20本书中检索信息。导入1到20本书信息时，请插入bookAddPoint 0。

此后，我们将书籍信息插入bookCatagory变量中，并使用bookCategory在单元格中显示书籍信息数据。

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
    }
}

我一直进行到这里，创建了一个显示20本书信息的单元格。

如果创建了显示第20本书信息的单元格，则

API.requestBookCategory (bookCategory: 9, bookAddPoint: 20, completionHandler: handleBooksCategory (books: error :))

我想像上面的代码一样运行将bookAddPoint从0修改为20的代码，以创建一个显示第21至40本书信息的单元格。我该怎么办？

Answer 1

在viewControoller中创建变量

var bookAddPoint = 0
var pageLength = 20

func callNextPageData(){
  bookAddPoint =  booksCategory?.books.count + 1
  API.requestBookCategory(bookCategory: 9, bookAddPoint: bookAddPoint, completionHandler: handleBooksCategory(books:error:))
  }

更改

func handleBooksCategory(books: Books?, error: Error?) {
    for book in books{
self.booksCategory.appen(book)
}
    DispatchQueue.main.async {
        self.collectionView.reloadData()
    }
}

更改 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
}

注意：：如果要在加载更多按钮时执行此操作，只需在按钮操作或tableView页脚操作中调用callNextPageData（）。

关于在Swift中重复加载collectionView单元格的问题

1 个答案: