ReactiveUI Xamarin iOS routing - xamarin

Question

I started experimenting with Reactive UI in Xamarin iOS and i'm confused to how I should handle routing.
Let's take the typical 'LoginViewModel' which has something like:
public class LoginViewModel : ReactiveObject
{
private readonly ReactiveCommand loginCommand;
public ReactiveCommand LoginCommand => this.loginCommand;
string username;
public string Username
{
get { return username; }
set { this.RaiseAndSetIfChanged(ref username, value); }
}
string password;
public string Password
{
get { return password; }
set { this.RaiseAndSetIfChanged(ref password, value); }
}
public LoginViewModel()
{
var canLogin = this.WhenAnyValue(
x => x.Username,
x => x.Password,
(u, p) => !string.IsNullOrEmpty(u) && !string.IsNullOrEmpty(p)
);
this.loginCommand = ReactiveCommand.CreateFromTask(async () =>
{
//Simulate login
await Task.Delay(2000);
return true;
}, canLogin);
}
}
And the ViewDidLoad (Controller):
this.WhenActivated(d =>
{
this.Bind(this.ViewModel, x => x.Username, x => x.Username.Text).DisposeWith(d);
this.Bind(this.ViewModel, x => x.Password, x => x.Password.Text).DisposeWith(d);
this.BindCommand(this.ViewModel, x => x.LoginCommand, x => x.LoginButton).DisposeWith(d);
});
This effectively binds the values of those UITextFields and Login button enable states + OnTouchUpInside
Now, in de documentation you can find the following about vm-routing: Android, iOS Native: Very difficult to make work
So what would be my options here ?
Expose a DidLogIn property (bool) and listen (in the view) on that with:
this.WhenAnyValue(x => x.ViewModel.DidLogIn)
.ObserveOn(RxApp.MainThreadScheduler)
.Subscribe(() => {
//Routing logic here
});
Are there other ways to handle view-routing (not vm-routing), I can find very little information about this

Answer 1

ReactiveUI's routing on Xamarin Forms is very easy, Xamarin Android/iOS is different history, but you can try ReactiveUI's interactions here is an example:
public class LoginViewModel : ReactiveObject
{
private readonly Interaction<Unit, Unit> _navigate;
public Interaction<Unit, Unit> Navigate => Navigate;
public ReactiveCommand<Unit,bool> LoginCommand { get; set; }
public LoginViewModel()
{
var canLogin = this.WhenAnyValue(
x => x.Username,
x => x.Password,
(u, p) => !string.IsNullOrEmpty(u) && !string.IsNullOrEmpty(p));
_navigate = new Interaction<Unit, Unit>();
LoginCommand = ReactiveCommand.CreateFromTask<Unit, bool>(async _ =>
{
/*Logic here*/
return true;
}, canLogin);
LoginCommand.Subscribe(async result =>
{
if (result)//this logic gets executed on your view by registering a handler :D
await await _navigate.Handle(Unit.Default) ;
else
{}
});
}
}
So in your view
this.WhenActivated(disposables =>
{
//bindings...
//Register a handler:
ViewModel.Navigate.RegisterHandler(async interaction =>
{
await NavigationLogic();
interaction.SetOutput(Unit.Default);
}).DisposeWith(disposables);
});
The example is not perfect, but is one way to do it.
I hope this helps you, you can find more on interactions in: https://reactiveui.net/docs/handbook/interactions/
Also there is an example in Xamarin Android + ReactiveUI: https://github.com/bl8/ReactivePhoneword
Regards