Question for those who use RxBindings - I noticed the following warning while moving to add the library to a new app I'm working on:

Warning: The created observable keeps a strong reference to

view

. Unsubscribe

* to free this reference. Since we're not supposed to hold hard references to an activity or fragment or view in a

ViewModel

from the architecture components, should we avoid passing an observable produced via RxBindings into a

ViewModel

?

I’m probably doing it wrong, but I pass RxBindings into the ViewModel. If that’s not how we should do it then definitely want to follow this thread

I'm going to do a test today and see if the activity is leaked on rotation when using rxbindings

🙏🏻

Any strong references to anything attached to the view in a ViewModel is a bad idea.

Recommendations for letting the ViewModel observe on user events?

There is a couple of ways to do it. You can inject an a CommandBus into the

ViewModel

. Another way to do it is by having a method on the

ViewModel

you call. Use an intermediate object that subscribes to the bindings and calls the method on the

ViewModel

You use the CommandBus along with RxBindings in production?

No I don't lol I don't us Rx at all.

Gotcha

In principal you need an intermediary object that facilitates communication.

There are tons of MVI references out there so if you’d like to share the ones you’ve looked at that’d be 👌🏻

Java or Kotlin?

Either

Ok, one sec

If I'm being honest, using an intermediary object is extremely disappointing. That adds a lot of boilerplate to what was approaching a concise flow

Yeah it is rather disappointing, especially given this talk which has RxBinding mapping into a network call with a promise that it could be retained between states 🤷🏻‍♂️

That video also comes years before

ViewModel

was a thing so

When that video came out people referenced Relays which I think end up being a similar concept to ViewModels or at least the concerns would be the same

Honsetly I think some sort of event handling system would be nice for Androids next Architecture component.

I mean we've moved very far out of the initial scope of questioning.

Yep

You too, thanks for the input!

@dewildte and if you want to get a return value when using a commands observable, you are screwed

You could embed a callback into the command

activity.enterPictureInPictureMode()) : Boolean for example

Nice code, care to add some context?

piece of code where you need a return value of "view" function, in which command pattern is impotent since its a two way comunication not just firing events

Update on this: I've come to realize that passing observables creates via rxbindings into your view model is just a bad move altogether. First of all it leaks, second of all when the user rotates the phone a new view is created and thus the old observable you're holding onto won't fire anymore. Unless you expose setters for those observables than you'll be SOL.

Yeeeeeah it seems like in general you’d want a light framework for consistent communication between View/ViewModel with RxBindings which is very disappointing

@alexsullivan114 I ran into something similar esp dealing with an EditText and its debounce. I just have the UI (activity/fragment) subscribe to it and relay it to ViewModel with a regular function which in turn feeds it a PublishSubject which is chained to backend (network and database)

@Sam That's exactly what I'm doing now. It's an unfortunate bit of boilerplate but it works for now. I wonder if there's a small library that could be used that alleviates some of this noise. You'd have to expose something that your view sort of "rebinds" to whenever the view is created that could then feed through to the view model. Anyways, thanks for the input!

There are some implementations of Uni Directional Flow that makes it a bit easier.

So one of my co-workers may have found an elegant solution for this using class delegation. We’re going to run through some tests internally but if that works I’m going to get them to write about on Medium

oh dope!