Cannot get swift view to update within multiple Lists and ForEach loop

Question

I am trying to get a my contentview to update correctly when I change a property in a child view. The view displays all the data correctly, but does not update until you back up a level in the UI and go back to the child view. The child view that does not update is embedded in NavigationView -> List -> Section -> NavigationLink -> List -> ForEach -> NavigationLink.

The same child view updates content view correctly when embedded in NavigationView -> List -> Section -> ForEach -> NavigationLink.

userManager is an instance of a class containing my data, added to the environment

user is an instance of NSManagedObject stored in userManager as an array, and created by a FetchRequest from a Core Data store

UserDetail is a view displaying properties of user, accessing userManager through @EnvironmentObject.

I have tried adding the id:.id and id:.self to the ForEach loop and did not work, I started with passing the userManager in as an @ObservedObject but that did not work either.

I want to keep this view structure because it displays my data nicely the way I want it in the UI, just does not update when the user property is changed.

I am just learning SwiftUI, I am sure I am missing something obvious but I cannot figure it out after searching.

I am attaching code snippets below:

var body: some View {
    NavigationView {
        List {
            
            Section("Active Users"){
                    ForEach(userManager.activeUsers) {user in
                        NavigationLink {
                            UserDetail( user: user) //*** this updates contentview correctly when user property is updated, this prints a confirmation to the console when user property is changed. 
                            
                        } label: {
                            
                            Text(user.wrappedName)
                        }
                    }
            }
            Section("Active Users"){
                NavigationLink {
                    List {
                        ForEach(userManager.activeUsers, id:\.id) { user in

                            NavigationLink {
                            
                                    UserDetail( user: user) //** this does not update content view when same property in user is updated. I prove this by a print statement which is not called. 
                                
                            
                            } label: {
                                
                                Text(user.wrappedName)
                                
                            }

                        }
                    }
                    
                } label: {
                    Text("Last Names A through H")
                }
            
            }

Here is the beginning of my UserManager class, I am using a number of computed properties to return subsets of the users array.

class UserManager: ObservableObject{
@Published var users: [UserCore]

init() {
    self.users = [UserCore]()
}

Here is the beginning of UserDetail View:

struct UserDetail: View {
    @Environment(\.managedObjectContext) var moc
    @Environment(\.presentationMode) var presentationMode
    @EnvironmentObject var userManager: UserManager

    var user: UserCore

Please provide enough code so others can better understand or reproduce the problem. — Community
– Community Bot, Commented Feb 10, 2022 at 0:50

ouflak · Accepted Answer · 2022-02-03 09:39:03Z

1

I just figured it out!

I programmatically ask the Button that changes the user state to send an objectWillChange.send() and that forces the content view to update and gives me the functionality I want:

Button(user.isActive ? "Deactivate User" : "Activate User"){
                        
                        user.isActive.toggle()
                        userManager.objectWillChange.send() // this fixed the problem!
                        try? moc.save()
                        presentationMode.wrappedValue.dismiss()

edited Feb 3, 2022 at 9:39

ouflak

2,56310 gold badges46 silver badges53 bronze badges

answered Feb 3, 2022 at 7:06

Jdoc68

112 bronze badges

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