无法在视图之间传递数据，也无法在第二个视图中更新 - SwiftUI

Question

我正在尝试在 this article 之后使用 @Published 和 @ObservedObject 在两个视图之间传递数据，但由于某些原因我无法传递数据， @Published只是保持初始状态，而不是在单击按钮时更改它。

第一个视图 ProductList2 导航到一个 tabView，我试图将数据传递到其中一个 tabView。任何帮助将不胜感激。

这是我创建 ObservableObject 和 @Published

的视图

class selectedApplication: ObservableObject {
    @Published var selectedApplication = "All"
}

struct ProductList2: View {
    @ObservedObject var selectedOption = selectedApplication()
    var products: [ProductModel] = productData
    
    var body: some View {
        VStack {
            HStack {
                List{
                    ForEach(applicationsArray, id: \.self) { item in
                        Button(action: {
                            self.selectedOption.selectedApplication = item
                        }) {
                            HStack(){
                                Image(item)
                                Text(item)
                            }
                        }
                    }
                }
            }
            List{
                let matchedItems = products.filter {
                    product in
                    let list = product.application
                    for item in list {
                        if item == selectedOption.selectedApplication {
                            return true
                        }
                    }
                    return false
                }
                ForEach(matchedItems) { item in
                    NavigationLink(destination: ProductTabView(product: item)) {
                        ProductListRow(product: item)
                    }
                }
            }
        }
    }
}

这是我尝试检索数据的选项卡视图：

struct ProductTab5View: View {
    var product: ProductModel
    @ObservedObject private var application = selectedApplication()
    
    var body: some View {
        VStack(alignment: .leading){
            Text(product.detailTabNames[3])
            ScrollView(.horizontal, showsIndicators: false) {
                HStack(alignment: .center, spacing: 0){
                    ForEach(product.application, id: \.self) { item in
                            Button(action: {
                                application.selectedApplication = item
                            }) {
                                VStack {
                                    Image(item)
                                    Text(item)
                                }
                            }
                    }
                }
            }            
            VStack(alignment: .center){
                Text(application.selectedApplication)
            }
        } 
    }
}

编辑：

我已经更新了导航 link 和 @ObservedObject 但仍然无法正常工作：

这是更新后的 ProductList2 NavigationLink：

ForEach(matchedItems) { item in
                        NavigationLink(destination: ProductTabView(product: item, application: selectedOption.selectedApplication)){
                            ProductListRow(product: item)
                        }
                    }

这是 ProductTab5View 上的 @ObservedObject，我也无法进行预览：

@ObservedObject private var application: selectedApplication

struct ProductTab5View_Previews: PreviewProvider {
    static var previews: some View {
        ProductTab5View(product: productData[0], application: application)
    }
}

Answer 1

您正在使用 selectedApplication 的两个不同实例：

struct ProductList2: View {
    @ObservedObject var selectedOption = selectedApplication()

struct ProductTab5View: View {
    ...
    @ObservedObject private var application = selectedApplication()

您需要在两个视图中使用相同的实例。

struct ProductTab5View: View {
    ...
    @ObservedObject var application: selectedApplication // declare only

// pass the already created instance to the child view
NavigationLink(destination: ProductTabView(product: item, application: selectedOption))

无法在视图之间传递数据，也无法在第二个视图中更新 - SwiftUI

Cannot pass data between views and also update in second view - SwiftUI

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