How to set addObserver in SwiftUI?

The accepted answer may work but is not really how you’re supposed to do this. In SwiftUI you don’t need to add an observer in that way.

You add a publisher and it still can listen to NSNotification events triggered from non-SwiftUI parts of the app and without needing combine.

Here as an example, a list will update when it appears and when it receives a notification, from a completed network request on another view / controller or something similar etc.

If you need to then trigger an @objc func for some reason, you will need to create a Coordinator with UIViewControllerRepresentable

struct YourSwiftUIView: View {

    let pub = NotificationCenter.default
            .publisher(for: NSNotification.Name("YourNameHere"))


    var body: some View {
        List() {
            ForEach(userData.viewModels) { viewModel in
                SomeRow(viewModel: viewModel)
            }
        }
        .onAppear(perform: loadData)
        .onReceive(pub) { (output) in
            self.loadData()
        }
    }

    func loadData() {
        // do stuff
    }
}