主页 / 问题 / 1341988
Accepted
Sherstyuk
Asked:2022-03-25 20:48:53 +0000 UTC2022-03-25 20:48:53 +0000 UTC

默默地将结果传递给第二个 View

  • 772

问题是将 ViewModel 的结果传递给任何 View

我的模特

    struct ItemsModel: Codable {
    
    var item1: String = ""
    var item2: String = ""
}

看法

    struct ContentView: View {
    
    @ObservedObject var resultViewModel = CalcViewModel()
    @State var isResultView: Bool = false
    
    var body: some View {
        NavigationView {
            Form {
                Section(header: Text("Ввод значения")) {
                    TextField("Введите число", text: $resultViewModel.itemModel.item1)
                    TextField("Введите число", text: $resultViewModel.itemModel.item2)
                }
                Section (header: Text("Ответ")) {
                    Text("\(resultViewModel.resultCalc())")
                }
                
                Button(action: {
                    self.isResultView.toggle()
                }, label: {
                    Text("Рассчитать")
                })
            }
            .sheet(isPresented: $isResultView) {
                        ResultView()
                    }
            .navigationBarTitle(Text("Calculate"))
        }
    }
}

视图模型

    class CalcViewModel: ObservableObject {
    
    @Published var itemModel = ItemsModel()
    
    var item1Double: Double {
        return Double(itemModel.item1) ?? 0
    }
    
    var item2Double: Double {
        return Double(itemModel.item2) ?? 0
    }
    
    func resultCalc() -> Double {
        
        let resultDouble = item1Double + item2Double
        print("👉 \(resultDouble)")
        
        return resultDouble
    }
}

查看将结果传递到哪里

    struct ResultView: View {
    
    @StateObject var vm = CalcViewModel()
    
    var body: some View {
        Text("Ответ: \(vm.resultCalc())")
    }
}
mvvm

1 个回答

  1. Best Answer

    有两种选择。传递给构造函数更容易：

    ...
let model:CalcViewModel
...
init(model:CalcViewModel){
   self.model = model
}
...

    第二个选项，在填充模型的视图中，添加：

    var body: some View {
        NavigationView {
            Form {
                Section(header: Text("Ввод значения")) {
                    TextField("Введите число", text: $resultViewModel.itemModel.item1)
                    TextField("Введите число", text: $resultViewModel.itemModel.item2)
                }
                Section (header: Text("Ответ")) {
                    Text("\(resultViewModel.resultCalc())")
                }
                
                Button(action: {
                    self.isResultView.toggle()
                }, label: {
                    Text("Рассчитать")
                })
            }
            .sheet(isPresented: $isResultView) {
                        ResultView()
                    }
            .navigationBarTitle(Text("Calculate"))
        }.environmentObject(resultViewModel)
    }

    以及您需要在哪里获取模型：

    struct ResultView: View {
    
    @EnvironmentObject vm:CalcViewModel
    
    var body: some View {
        Text("Ответ: \(vm.resultCalc())")
    }
}

    如果从您的代码中抽象使用，这是一个示例environmentObject：

    // Our observable object class
class GameSettings: ObservableObject {
    @Published var score = 0
}

// A view that expects to find a GameSettings object
// in the environment, and shows its score.
struct ScoreView: View {
    @EnvironmentObject var settings: GameSettings

    var body: some View {
        Text("Score: \(settings.score)")
    }
}

// A view that creates the GameSettings object,
// and places it into the environment for the
// navigation view.
struct ContentView: View {
    @StateObject var settings = GameSettings()

    var body: some View {
        NavigationView {
            VStack {
                // A button that writes to the environment settings
                Button("Increase Score") {
                    settings.score += 1
                }

                NavigationLink(destination: ScoreView()) {
                    Text("Show Detail View")
                }
            }
            .frame(height: 200)
        }
        .environmentObject(settings)
    }
}

    停靠在您的问题和文章上

    • 1

相关问题