I am busy in a project where the architect said that we have not to use

Boolean

as Flag in the viewModel, but

Observable<Boolean>

and so on for everything because he claims that imperative and functional paradigms should not be used togheter. So I am in a situation where if I want to control a simple true false, have to make a

PublishSubject

, start it with a value, and then bind it, while I think would be much more efficient to do a simple Boolean

viewModel.isSomethingTrue

. Kotlin is not AFAIK a reactive functional language as clojure for instance, so I guess under the hood everytime I use RXJAVA I am going to build a lot on top of an Observable pattern a Boolean anyway! * Is reasonable and more performance effective to combine RXJAVA with ’Imperative” as I think, or I should bind evey single thing and make my Activity classess much more verbose as the architect is saying? *

Does that boolean ever change? If so, I think exposing it as an observable makes sense. If it's like "View has loaded" or some shit that only ever happens once I think it's overkill. The benefits of exposing data as observables is that it represents data that actually changes. If you're in a scenario where you need to react to whatever that boolean represents changing then reactive programming ( I don't think it's fair to call RxJava functional programming per say) is helpful.

is a flag variable, that I set false at the beginning, and then inside an

RXClick( button_send).subscribe{

becomes true, so that I can use it into onBackPressed to say finish()

So basically you have some boolean that gets set and then you check that boolean in

onBackPressed

to see if you should do something or another?

yes exactly

Then I'd say having that boolean represented as a stream is overkill and does not serve a purpose.

because I need to go in the `onActivityResult `of the other activity of the previous activity so to refresh