Are changes to published embedded objects really not detected in SwiftUI?

Question

Stokestack OP

Created Jan ’24

Replies 3

Boosts 0

Participants 4

Let's say I have a class to represent a user:

class User : Equatable, Codable, ObservableObject
{
	@Published var	ID: String = ""
	@Published var	username:  String = ""
	@Published var	firstName: String = ""
	@Published var	lastName: String = ""
	@Published var	EMail: String = ""
	@Published var	phoneNbr: String = ""
	@Published var	avatarURL: String = ""
	@Published var	mediaServiceID: String = ""
	@Published var	validated: Bool = false
...
}

I also have a controller ("viewmodel") to broker interactions between SwiftUI views and the User. It contains a User object as:

@MainActor class UserManager : ObservableObject
{
	@Published var user: User
...
}

And finally of course the view, into which I pass the UserManager upon initialization:

struct StartupView: View
{
	@ObservedObject var userMgr: UserManager
...
}

Changing published members of the User embedded in UserManager does not trigger a UI refresh. That strikes me as broken, since everything is published. Is it expected behavior?

Boost

Answer 1

Dirk-FU OP

Jan ’24

This works as intended. Try if using the new Observation helps in your case.

0

Answer 2

szymczyk OP

Jan ’24

The view that owns the ObservableObject must use the @StateObject property.

struct StartupView: View
{
	@StateObject var userMgr: UserManager
...
}

Use @ObservedObject in any other views that need access to the user manager.

0

Answer 3

hmuronaka OP

Jan ’24

How about trying this?

@MainActor class UserManager: ObservableObject {
    @Published var user: User
    
    private var cancelSet: Set<AnyCancellable> = .init()
    
    init() {
        self.user = User()
        self.user.objectWillChange.sink { [weak self] in
            self?.objectWillChange.send()
        }
        .store(in: &cancelSet)
        Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { _ in
            Task { @MainActor in
                self.user.ID += "1"
            }
        }
    }
}



struct ContentView: View {
    @ObservedObject var userManager: UserManager
    
    var body: some View {
        VStack {
            Text("\(userManager.user.ID)")
        }
        .padding()
    }
}

1