I am working through the SwiftUI starter project, but running under Xcode 12 beta 4. I am trying to get the project to run with the new format, iDineApp.swift instead of the SceneDelegat.swift. I have added envrionment objects to all the views to handle the order. I am not sure what I am missing though. The full error text when I build and run is

2020-08-15 10:42:26.865892-0400 iDine[58795:3690986] libMobileGestalt MobileGestaltCache.c:38: No persisted cache on this platform.
Fatal error: No ObservableObject of type Order found. A View.environmentObject(_:) for Order may be missing as an ancestor of this view.: file SwiftUI, line 0
2020-08-15 10:42:31.094675-0400 iDine[58795:3690785] Fatal error: No ObservableObject of type Order found. A View.environmentObject(_:) for Order may be missing as an ancestor of this view.: file SwiftUI, line 0

What am I missing?

Could you please share your code otherwise helping you will be difficult

Sure. I am working from this tutorial: https://www.hackingwithswift.com/quick-start/swiftui/swiftui-tutorial-building-a-complete-project

And am stuck on adding the tab view https://www.hackingwithswift.com/quick-start/swiftui/adding-tabview-and-tabitem

My main app code

@main
struct iDineApp: App {
    @EnvironmentObject var order: Order
    var body: some Scene {
        WindowGroup {
            AppView()
        }
    }
}

struct iDineApp_Previews: PreviewProvider {
    static let order = Order()

    static var previews: some View {
        AppView().environmentObject(order)
    }
}

The order

import SwiftUI

class Order: ObservableObject {
    @Published var items = [MenuItem]()

    var total: Int {
        if items.count > 0 {
            return items.reduce(0) { $0 + $1.price }
        } else {
            return 0
        }
    }

    func add(item: MenuItem) {
        items.append(item)
    }

    func remove(item: MenuItem) {
        if let index = items.firstIndex(of: item) {
            items.remove(at: index)
        }
    }
}

ContentView

struct ContentView: View {
    let menu = Bundle.main.decode([MenuSection].self, from: "menu.json")
    var body: some View {
        NavigationView{
            List {
                ForEach(menu) { section in
                    Section(header: Text(section.name)) {

                        ForEach(section.items) { item in
                            ItemRow(item: item)
                    }
                    }
                }
            }
            .navigationBarTitle("Menu")
            .listStyle(InsetGroupedListStyle())
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

ItemDetail

struct ItemDetail: View {
    @EnvironmentObject var order: Order

    var item: MenuItem
    var body: some View {
        VStack {
            ZStack(alignment: .bottomTrailing) {
                Image(item.mainImage)
                Text("Photo: \(item.photoCredit)")
                    .padding(4)
                    .background(Color.black)
                    .font(.caption)
                    .foregroundColor(.white)
                    .offset(x: -5, y: -5)
                    .opacity(0.75)
            }
            Text(item.description).padding()
            Button("Order This") {
                self.order.add(item: self.item)
            }.font(.headline)
            Spacer()
        }.navigationBarTitle(Text(item.name), displayMode: .inline)
    }
}

struct ItemDetail_Previews: PreviewProvider {
    static let order = Order()

    static var previews: some View {
        NavigationView
        {        ItemDetail(item: MenuItem.example).environmentObject(order)
        }
    }
}

OrderView

struct OrderView: View {
    @EnvironmentObject var order: Order

    var body: some View {
        NavigationView {
            List {
                Section {
                    ForEach(order.items) { item in
                        HStack {
                            Text(item.name)
                            Spacer()
                            Text("$\(item.price)")
                        }
                    }
                }

                Section {
                    NavigationLink(destination: Text("Check out")) {
                        Text("Place Order")
                    }
                }
            }
            .navigationBarTitle("Order")
            .listStyle(GroupedListStyle())
        }
    }
}

struct OrderView_Previews: PreviewProvider {
    static let order = Order()

    static var previews: some View {
        OrderView().environmentObject(order)
    }
}

AppView

struct ItemRow: View {
    static let colors: [String: Color] = ["D": .gray, "G": .yellow, "N": .orange, "S": .red, "V": .green]
    var item: MenuItem
    var body: some View {
        NavigationLink(destination: ItemDetail(item: item))
        {
            HStack {
                Image(item.thumbnailImage)
                    .clipShape(Circle())
                    .overlay(Circle().stroke(Color.gray, lineWidth: 2.0))
                VStack(alignment: .leading) {
                    Text(item.name)
                        .font(.headline)
                    Text("$\(item.price)")
                }

                Spacer()

                ForEach(item.restrictions, id: \.self) {
                    restriction in Text(restriction)
                        .font(.caption)
                        .fontWeight(.black)
                            .padding(5)
                            .background(Self.colors[restriction, default: .black])
                            .clipShape(Circle())
                            .foregroundColor(.white)
                }
            }
        }
    }
}

struct ItemRow_Previews: PreviewProvider {
    static var previews: some View {
        ItemRow(item: MenuItem.example)
    }
}

Item Row

struct ItemRow: View {
    static let colors: [String: Color] = ["D": .gray, "G": .yellow, "N": .orange, "S": .red, "V": .green]
    var item: MenuItem
    var body: some View {
        NavigationLink(destination: ItemDetail(item: item))
        {
            HStack {
                Image(item.thumbnailImage)
                    .clipShape(Circle())
                    .overlay(Circle().stroke(Color.gray, lineWidth: 2.0))
                VStack(alignment: .leading) {
                    Text(item.name)
                        .font(.headline)
                    Text("$\(item.price)")
                }

                Spacer()

                ForEach(item.restrictions, id: \.self) {
                    restriction in Text(restriction)
                        .font(.caption)
                        .fontWeight(.black)
                            .padding(5)
                            .background(Self.colors[restriction, default: .black])
                            .clipShape(Circle())
                            .foregroundColor(.white)
                }
            }
        }
    }
}

struct ItemRow_Previews: PreviewProvider {
    static var previews: some View {
        ItemRow(item: MenuItem.example)
    }
}

Thanks That fixed it.