Why does ForEach update for DisclosureGroup and not my Picker?

Question

I am trying to update a state variable that is an array of Strings that I get back from an API call. I want to display this array in a Picker. However, my Picker is completely blank. I know my api is coming back with values because one of the ForEach's is updating.

struct SelectModeView: View {
    @StateObject var viewModel = SelectModeViewModel()
    @State private var selectionB: String = ""
    
    var body: some View {
           ZStack {
               Color.white
                   .edgesIgnoringSafeArea(.all)
               VStack {
                     
                       VStack(spacing: 08) {
                           Text("PICKER STYLE")
                                 .font(.largeTitle)
                               Text("Select Project")
                                   
                           Picker("Select Project", selection: self.$selectionB) {
                               ForEach(self.projects, id: \.self) { option in
                                   Text(option)
                               }
                           }
                           .accentColor(Color.black)
                       }
                       
                       Text("DISCLOSURE GROUP STYLE")
                             .font(.largeTitle)
                       DisclosureGroup(self.selectionC == "" ? "Pick Project" : self.selectionB, isExpanded: self.$isProjectOpen, content: {
                           ScrollView(.vertical, showsIndicators: false) {
                               VStack {
                                   ForEach(self.projects, id: \.self) { option in
                                       Text(option)
                                           .padding()
                                   }
                               }
                           }
                           .frame(height: 240)
                       })
                       .accentColor(Color.black)
                       .padding(.horizontal, 64)
               }
           }
           .onAppear {
               print("selectModeView appeared")

               self.viewModel.gatherProjectListAPI()
           }
           .onReceive(self.viewModel.$projectList, perform: { list in
               print("Received project list: \(list)")
               self.projects = list
           })
           
       }
}
    

class SelectModeViewModel: ObservableObject {
    @Published var projectList: [String] = []
    func gatherProjectListAPI() {
     self.projectList.append("Project1")
     self.projectList.append("Project2")
     self.projectList.append("Project3")
         self.projectList.append("Project4")

//  same result as self.projectList = ["Project1", "Project2", "Project3", "Project4"]
     }
    
}

I have tried not using an id, going by only count of the array (0..<projects.count), not using " option in" and using $0 instead, using only the published variable in the viewModel (which would be preferred to do) and not only having the published variable being received and updating a state variable and have still not been able to get the Picker to update.

Have you tried using viewModel.projectList in the ForEach, instead of your nonsensical self.projects. Note, there is no need for your .onReceive(...), the projectList is already being observed by the view. Note also, using ForEach(viewModel.projectList, id: \.self) may work but it is not appropriate, you should make sure the elements are unique by having a unique id. Use the id for the selection and for Text(option).tag(id). With the current code, you should add selectionB = viewModel.projectList.first ?? "" to your .onAppear. — workingdog support Ukraine
– workingdog support Ukraine, Commented Jul 21 at 22:49

workingdog support Ukraine · Accepted Answer · 2025-07-21 23:27:15Z

Try this approach using viewModel.projectList and a dedicated structure (struct Project) for your projectList. There is no need for your .onReceive(...), the projectList is already being observed by the view.

Note the Text(option.name).tag(option) and the ForEach(...). Initialise the selections in the .onAppear as shown.

You should not use ForEach(self.projects, id: \.self).


struct ContentView: View {
    var body: some View {
        SelectModeView()
    }
}

struct Project: Identifiable, Hashable {  // <--- here
    let id = UUID()
    var name: String
}

class SelectModeViewModel: ObservableObject {
    @Published var projectList: [Project] = []  // <--- here
    
    func gatherProjectListAPI() {
        self.projectList.append(Project(name: "Project1"))  // <--- here
        self.projectList.append(Project(name: "Project2"))
        self.projectList.append(Project(name: "Project3"))
        self.projectList.append(Project(name: "Project4"))
    }
}

struct SelectModeView: View {
    @StateObject private var viewModel = SelectModeViewModel()
    @State private var selectionB = Project(name: "") // <--- here
    @State private var selectionC = Project(name: "") // <--- here
    @State private var isProjectOpen = true
    
    
    var body: some View {
        ZStack {
            Color.white
                .edgesIgnoringSafeArea(.all)
            VStack {
                
                VStack(spacing: 08) {
                    Text("PICKER STYLE")
                        .font(.largeTitle)
                    Text("Select Project")
                    
                    Picker("Select Project", selection: self.$selectionB) {
                        ForEach(viewModel.projectList) { option in  // <--- here
                            Text(option.name)
                                .tag(option) // <--- here
                        }
                    }
                    .accentColor(Color.black)
                }
                
                Text("DISCLOSURE GROUP STYLE")
                    .font(.largeTitle)
                DisclosureGroup(self.selectionC.name == "" ? "Pick Project" : self.selectionB.name, isExpanded: self.$isProjectOpen, content: {
                    ScrollView(.vertical, showsIndicators: false) {
                        VStack {
                            ForEach(viewModel.projectList) { option in  // <--- here
                                Text(option.name)
                                    .tag(option) // <--- here
                                    .padding()
                            }
                        }
                    }
                    .frame(height: 240)
                })
                .accentColor(Color.black)
                .padding(.horizontal, 64)
            }
        }
        .onAppear {
            print("selectModeView appeared")
            viewModel.gatherProjectListAPI()
            selectionB = viewModel.projectList.first ?? Project(name: "")  // <--- here
            selectionC = selectionB // <--- here
        }
    }
}

Collectives™ on Stack Overflow

Why does ForEach update for DisclosureGroup and not my Picker?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related