使用SwiftUI从json数据加载更多功能

import SwiftUI
import Combine

struct ContentView: View {
    @State private var items: [Item] = []
    @State private var isLoading = false
    @State private var hasMoreData = true
    private var cancellable: AnyCancellable?

    var body: some View {
        List(items) { item in
            Text(item.title)
        }
        .onAppear {
            loadMoreItems()
        }
        .listRowInsets(.init(top: 0, leading: 0, bottom: 0, trailing: 0))
        .overlay(
            Group {
                if isLoading {
                    ProgressView("Loading...")
                }
            }
            .frame(height: 50)
            .padding(.vertical)
        )
    }

    private func loadMoreItems() {
        guard !isLoading && hasMoreData else { return }
        isLoading = true

        cancellable = APIService.fetchItems(page: items.count / 10 + 1)
            .sink(receiveCompletion: { completion in
                self.isLoading = false
                switch completion {
                case .finished:
                    break
                case .failure(let error):
                    print("Error fetching data: \(error)")
                }
            }, receiveValue: { newItems in
                if newItems.isEmpty {
                    hasMoreData = false
                } else {
                    items.append(contentsOf: newItems)
                }
            })
    }
}

struct Item: Identifiable {
    let id = UUID()
    let title: String
}

class APIService {
    static func fetchItems(page: Int) -> AnyPublisher<[Item], Error> {
        // Replace with actual API call
        return URLSession.shared.dataTaskPublisher(for: URL(string: "https://api.example.com/items?page=\(page)")!)
            .map { $0.data }
            .decode(type: [Item].self, decoder: JSONDecoder())
            .eraseToAnyPublisher()
    }
}