来自 Medium 教程的 Swift 分页方法抛出错误

Question

我需要了解分页对于我现在正在做的项目是如何工作的。 我的朋友向我推荐了这个教程：https://medium.com/swlh/easy-pagination-in-swiftui-da9e1fe3e25e和@loremipsum 帮助解决了我遇到的几个问题。 还是教程中的URL：

"https://testURL.com"

需要一个帐户并且实际上不允许创建帐户（即使我想创建一个）。 所以我使用了 URL 我知道 API 键。

编码：

内容视图文件：

import SwiftUI

struct Members: View {
    @ObservedObject var memberData = MemberData()
    
    var body: some View {
        NavigationView {
            List {
                // 1. Members
                ForEach(memberData.members) { item in
                    Text(items.Item) /* No exact matches in call to initializer */
                }
                
                // 2. Activity Indicator. Last element of list.
                // Show activity spinner if backend has more data.
                // Its onAppear method is used to load new members. Pagination done.
                if memberData.membersListFull == false {
                    ProgressView()
                    .onAppear {
                        memberData.fetchMembers()
                    }
                }
            }
            .navigationBarTitle("Members")
        }
    }
}

会员资料文件：

import Foundation
import Combine

class MemberData: ObservableObject {
    @Published var members = [Item]()
    
    // Tells if all records have been loaded. (Used to hide/show activity spinner)
    var membersListFull = false
    // Tracks last page loaded. Used to load next page (current + 1)
    var currentPage = 0
    // Limit of records per page. (Only if backend supports, it usually does)
    let perPage = 20
    
    let url = URL(string:"https://api.github.com/search/repositories?q=Core-Data&per_page=\(currentPage+1)&perPage=\(perPage)")! /* 1) Cannot use instance member 'currentPage' within property initializer; property initializers run before 'self' is available; 2) Cannot use instance member 'perPage' within property initializer; property initializers run before 'self' is available */

    private var cancellable: AnyCancellable?
    
    func fetchMembers() {
        cancellable = URLSession.shared.dataTaskPublisher(for: url)
            .tryMap { $0.data }
            .decode(type: [Item].self, decoder: JSONDecoder())
            .receive(on: RunLoop.main)
            .catch { _ in Just(self.members) }
            .sink { [weak self] in
                self?.currentPage += 1
                self?.members.append(contentsOf: $0)
                // If count of data received is less than perPage value then it is last page.
                if $0.count < perPage { /* Reference to property 'perPage' in closure requires explicit use of 'self' to make capture semantics explicit */
                    self?.membersListFull = true
                }
        }
    }
}

API 调用文件：

import SwiftUI

struct Root: Codable {
    let items: [Item]

    enum CodingKeys: String, CodingKey {
        case items
    }
}

struct Item: Identifiable, Codable {
    let id: Int
    let htmlUrl: String
    let fullName: String

    enum CodingKeys: String, CodingKey {
        case id
        case htmlUrl = "html_url"
        case fullName = "full_name"
    }
}

我得到 4 个错误。 一个在 ContentView 中，3 个在成员数据文件中。 我已将它们全部添加为相应文件中的注释。

如果可以的话请帮忙：）