I've this code in a `ViewModel`:

private val testSingle = Single.just("item1")

private val foo = testPublishSubject.startWith(testSingle.toObservable().doOnNext {
    Timber.i(">>> single on next: $it")
}).doOnNext {
    Timber.i(">>> PS on next: $it")
}

fun onSomeEvent() {
    testPublishSubject.onNext("item2")
}

So it's a

PublishSubject

that gets initialized with a

Single

. On certain event, I push a new value to the subject. So far so good! The problem: I navigate to next screen and navigate back. Then the subject is reset to the initial

Single

value ("item1"). Why? The

ViewModel

is not reinitialized.

is the viewmodel in an activity or fragment?

Could you confirm again the lifecycle of the viewModel by logs inside init.

actually, the reason is that the fragment subscribes to

foo

again. (It's in a fragment and it subscribes in

onCreateView

)

yeah, the question is why the other value wasnt cached

because the fragment disposes the subscription and subscribes again

that should do it

probably yeah

what does the mySingleCall() function look like - it sounds like something has been cached at that level

not really...

fun selectedModel(): Single<Optional<Model>> =
    (preferences.getString(SELECTED_MODEL)?.let {
        Some(Model(it))
    } ?: None).let{ Single.just(it) }

hmm. strange

that code can actually be simplified to

fun selectedModel() = Single.just("foo")

if that was the one that was a “val” earlier, then it would capture the value at that point. You could rewrite as

Single.fromCallable { /* fetch from preferences here */  }

but it's not a

val

. I posted this snippet above:

private val foo = testPublishSubject.startWith(myRepo.mySingleCall().toObservable())