API 調用第二次與組合不起作用

Question

我試圖用URLSession.shared.dataTaskPublisher UITableView一次按預期工作，但第二次當我嘗試獲取更多項目時，值永遠不會sink 。

    private var filteredShows: Show?
    private var currentPage : Int = 1
    private var isLoadingList : Bool = false
    private var cancellable: AnyCancellable?

    override func viewDidLoad() {
       super.viewDidLoad()
       fetchShows(currentPage)
    }

    private func fetchShows(_ pageNumber: Int) {
       cancellable = ShowService().getShows(pageNumber: String(pageNumber)).map { [weak self] shows in
          self?.isLoadingList = false
          self?.filteredShows = shows
          }.sink { _ in } receiveValue: { [weak self] _story in
             self?.isLoadingList = false
             self?.showsTableView.reloadData()
          }
   }

  extension ViewController: UITableViewDataSource, UITableViewDelegate {
     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        filteredShows?.count ?? 0
     }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
       let cell = UITableViewCell(style: .default, reuseIdentifier: "cell");

       cell.textLabel?.text = filteredShows?[indexPath.row].name
       return cell
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
       if (((scrollView.contentOffset.y + scrollView.frame.size.height) > scrollView.contentSize.height ) && !isLoadingList) {
          self.isLoadingList = true
          self.loadMoreItemsForList()
       }
    }
 }

    class ShowService: RequestProtocol {

       func getShows(pageNumber: String) -> AnyPublisher<Show, Error> {
    
        guard let url = URL(string: "https://api.tvmaze.com/shows?page=%5C(pageNumber)") else { fatalError("wrong url") }
    
        return URLSession.shared.dataTaskPublisher(for: url)
           .receive(on: RunLoop.main)
           .map( .data )
           .decode(type: Show.self, decoder: JSONDecoder())
           .catch { _ in Empty<Show, Error>() }
           .eraseToAnyPublisher()
        }
     }

Answer 1

將 diffable tableview 與快照一起使用，快照將自動更新，值得麻煩，因為與 combine 一起使用效果最佳。