Best-practices to download data from server in SwiftUI

Question

My question is a conceptual question.

I have the following code:

struct CategoriesList : View {

    @State pri         


        

Answer 1

You could take a look at my answer here.

Basically you create a model object conforming to BindableObject :

class LoginModel : BindableObject {

    var didChange = PassthroughSubject()

    private(set) var username: String? {
        didSet {
            didChange.send(self)
        }
    }

    func load() {
        DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
            self.username = "Sorin"
        }
    }
}

This example simulates an async server call by using the plain ol' asyncAfter.

Then, the View links with it and it's automatically updated when the model changes.

public struct LoginScreen: View {

    @ObjectBinding var loginObject = LoginModel()

    public var body: some View {
        Group {
            if login.username == nil {
                Text("Trying to login, please wait...")
            } else {
                Text("Successful login, the username is \(loginObject.username!)")
            }
        }.onAppear {
            self.loginObject.load()
        }
    }
}

The key here is to avoid trying to make the View perform anything related to the Model, except displaying it. SwiftUI will resist you all the way :-)