ios - SwiftUI使用 View 模型模式以两种不同方式打开 View

Question

我需要打开一个名为RequestDetails的 View 。

在两种情况下都可以打开此 View 。

提供数据以打开此请求

提供对Firestore文档

的引用

在这种情况下，我没有此特定请求的所有详细信息，但仅引用了Firestore文档。我使用此引用在此 View 出现后立即进行查询，并获取有关此请求的详细信息。 RequestDetail(reference: reference)

class RequestViewModel: ObservableObject {
    @Published var request: RequestModel?
    @Published var requestReference: DocumentReference?

    init(request: RequestModel? = nil, requestReference: DocumentReference? = nil) {
        self.request = request
        self.requestReference = requestReference
    }

    func loadRequest() {
        FirestoreService().fetchDocument(documentReference: self.requestReference) { (request: RequestModel) in
            DispatchQueue.main.async {
                self.request = request
            }
        }
    }

}

struct RequestDetails: View {
    @State var reference: DocumentReference?
    @State var request: RequestModel?

    @ObservedObject var vm: RequestViewModel

    var body: some View {
        VStack {
            if request != nil {
                Text(self.request?.senderFirstName)
            }
        }.onAppear {
            if self.vm.package == nil {
                self.vm.loadRequest()
            }
        }
    }
}

struct Home: View {
    var request: RequestModel
    var reference: DocumentReference

    var body: some View {
        VStack {
            RequestDetail(request: request)
            RequestDetail(reference: reference)
        }
    }
}

问题是我遇到了很多错误，并且想知道背后的逻辑是否正确。我是否以正确的方式使用 View 模型模式？

Answer 1

以下内容适合遵循MVVM概念

struct RequestDetails: View {
    @ObservedObject var vm: RequestViewModel

    var body: some View {
        VStack {
            if self.vm.request != nil {
                Text(self.vm.request!.senderFirstName)
            }
        }.onAppear {
            if self.vm.request == nil {
                self.vm.loadRequest()
            }
        }
    }
}

struct Home: View {
    var request: RequestModel
    var reference: DocumentReference

    var body: some View {
        VStack {
            RequestDetail(vm: RequestViewModel(request: request))
            RequestDetail(vm: RequestViewModel(reference: reference))
        }
    }
}