Question

我试图在this article之后使用@Published和@ObservedObject在2个视图之间传递数据，但是由于某些原因，我无法传递数据，@Published一直保持在初始状态下，它是给定的，而不是在单击按钮时更改。

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tabViews。任何帮助将不胜感激。

这是我在其中创建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)
                    }
                }
            }
        }
    }
}

这是我试图在其中检索数据的tabview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：

我已经更新了导航链接和@ObservedObject，但仍然无法使它工作：

这是更新的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

1 个答案: