firebase - SwiftUI:从 DetailView 更新 Firestore

Question

我正在努力将 Firestore 存储库整合到 SwiftUI 2 应用程序中。 ListView 会适当加载，并在 Firestore 集合中的数据更改时自动刷新。 NavigationLink 正确加载适当的 DetailView。 DetailView 上的一个按钮设置为更改相关文档中的数据，并且工作正常，但是 DetailView 页面没有刷新正确的数据(退出到 ListView 并返回时正确显示)；同样，DetailView 不会响应在其他地方对集合所做的更改。

我尝试使用 ObservedObject 和 State 的各种配置，但一直无法获得预期的结果。

如有任何帮助，我们将不胜感激。下面列出的代码片段显示了流程，并以状态字段为例。

客户资料库

class CustomerRepository: ObservableObject {
    
    private let path: String = "customers"
    private let store = Firestore.firestore()
    @Published var customers: [Customer] = []
    
    private var cancellables: Set<AnyCancellable> = []
    
    init() {
        store.collection(path)
            .addSnapshotListener { querySnapshot, error in
                if let error = error {
                    print("Error getting customers \(error.localizedDescription)")
                    return
                }
                
                self.customers = querySnapshot?.documents.compactMap { document in
                    
                    try? document.data(as: Customer.self)
                    
                } ?? []
            }
    }
    
    func update(_ customer: Customer) {
        guard let customerID = customer.id else { return }
        
        do {
            try store.collection(path).document(customerID).setData(from: customer)
        } catch {
            fatalError("Unable to update record: \(error.localizedDescription)")
        }
    }
}

CustomerListViewModel

class CustomerListViewModel: ObservableObject {
    
    @Published var customerViewModels: [CustomerViewModel] = []
    
    private var cancellables: Set<AnyCancellable> = []
    
    @Published var customerRepository = CustomerRepository()
    
    init() {
        customerRepository.$customers.map { customers in
            customers.map(CustomerViewModel.init)
        }
        .assign(to: \.customerViewModels, on: self)
        
        .store(in: &cancellables)
    }
}

CustomerViewModel

class CustomerViewModel: ObservableObject, Identifiable {
    
    private let customerRepository = CustomerRepository()
    
    @Published var customer: Customer
    
    private var cancellables: Set<AnyCancellable> = []
    
    var id = ""
    
    init(customer: Customer) {
        self.customer = customer
        
        $customer
            .compactMap { $0.id }
            .assign(to: \.id, on: self)
            .store(in: &cancellables)
    }
    
    func update(customer: Customer) {
        customerRepository.update(customer)
    }
}

客户 ListView

struct CustomerListView: View {
    
    @ObservedObject var customerListViewModel = CustomerListViewModel()

    var body: some View {
        NavigationView {
            List {
                ForEach(customerListViewModel.customerViewModels) { customerViewModel in
                    
                    NavigationLink(
                        destination: CustomerDetailView(customerViewModel: customerViewModel)) {
                            CustomerCell(customerViewModel: customerViewModel)
                        }
                }
            }
        }
    }
}

CustomerDetailView

struct CustomerDetailView: View {
    var customerViewModel: CustomerViewModel
    
    var body: some View {
        VStack {
            
            Text(customerViewModel.customer.status.description)
            
        }.onTapGesture {
                    nextTask()
                }
    }

private func nextTask() {
        switch customerViewModel.customer.status {
        case .dispatched:
            customerViewModel.customer.status = .accepted
        
...

        default:
            return
        }
        
        update(customer: customerViewModel.customer)
        
    }
    
    func update(customer: Customer) {
        customerViewModel.update(customer: customer)
    }
}

Answer 1

经过一些重新配置，以及这个例子的帮助:

https://peterfriese.dev/swiftui-firebase-update-data/

我能够解决我的问题。以下是修改后代码的分割，以防对其他人有所帮助....

CustomerViewModel

class CustomerViewModel: ObservableObject, Identifiable {
    
    @Published var customer: Customer
    @Published var modified = false
    
    private var cancellables: Set<AnyCancellable> = []
    
    init(customer: Customer = Customer(status: .new)) {
        self.customer = customer
        
        self.$customer
            .dropFirst()
            .sing { [weak self] customer in
               self?.modified = true
            }
            .store(in: &cancellables)
    }
    
    func handleDoneTapped() {
      self.updateOrAddCustomer()
  }
}

客户 ListView

// Snip to Navigation Link

    NavigationLink(
        destination: CustomerDetailView(customerViewModel: CustomerViewModel(customer: customerViewModel.customer))) {
                            CustomerCell(customerViewModel: customerViewModel)
                        }

CustomerDetailView

struct CustomerDetailView: View {
    @ObservedObject var customerViewModel = CustomerViewModel()
    
    var body: some View {
        VStack {
            
            Text(customerViewModel.customer.status.description)
            
        }.onTapGesture {
                    nextTask()
                }
    }

private func nextTask() {
        switch customerViewModel.customer.status {
        case .dispatched:
            customerViewModel.customer.status = .accepted
        
...

        default:
            return
        }
        
        update(customer: customerViewModel.customer)
        
    }
    
    func update(customer: Customer) {
        customerViewModel.handleDoneTapped()
    }
}