@ObservedObject不更新

Question

我试图用一个简单的可观察模式来更新视图，但由于某种原因，它不会发生。发布服务器得到更新，但订阅服务器没有更新。我已经简化为下面的代码。单击Add按钮时，视图和变量都不会更新。

我使用这个函数(NetworkManager.shared.saveNew())，因为我在CloudKit通知之后进行更新。如果你知道解决办法，我会很高兴知道的！

import SwiftUI
import Combine

public class NetworkManager: ObservableObject {
    static let shared = NetworkManager()

    @Published var list = [DataSource]()

    init() {
        self.list = [DataSource(id: "Hello", action: [1], link: "http://hello.com", year: 2020)]
    }

    func saveNew(item: DataSource) {
        self.list.append(item)

    }
}

struct DataSource: Identifiable, Codable {

    var id: String
    var action: [Int]
    var link: String
    var year: Int

    init(id: String, action: [Int], link: String, year: Int) {
        self.id = id
        self.action = action
        self.link = link
        self.year = year
    }
}


struct ContentView: View {

    @ObservedObject var list = NetworkManager()

    var body: some View {
        VStack {
            Button("Add") {
                NetworkManager.shared.saveNew(item: DataSource(id: "GoodBye", action: [1], link: "http://goodbye", year: 2030))

            }
            List(list.list, id:\.id) { item in
                Text(item.id)
            }
        }

    }
}

Answer 1

应该使用相同的NetworkManager实例，因此这里是固定的变体(最好将管理器命名为manager，而不是list)。

struct ContentView: View {

    @ObservedObject var manager = NetworkManager.shared // << fix !!

    var body: some View {
        VStack {
            Button("Add") {
                self.manager.saveNew(item: DataSource(id: "GoodBye", action: [1], link: "http://goodbye", year: 2030))

            }
            List(manager.list, id:\.id) { item in
                Text(item.id)
            }
        }

    }
}