Hi guys, not sure if this belong to this channel but ill try. im using Compose + StateFlow and i have a function that will trigger an event (i’ll call it

authMethod

)

viewModel.authMethod.onEach {
            Log.e("i'm here", "yes im here ${it}")
        }.collect()

this will be trigger the first time and every time after i change the value on the viewModel. my issue is that when i push new view (using

Navigation alpha06

) and i pop back the

onEach

will be triggered again. How could i only tell

authMethod

to be triggered only on changes and not every-time the compose is rendering ?🌈 With liveData i had the observable that only triggers on changes, but i can not find the equivalent on StateFlow :/

where are you calling

collect()

from?

LaunchedEffect

?

yes, it looks like this

val coroutineScope = rememberCoroutineScope()

    LaunchedEffect(coroutineScope) {
        viewModel.authMethod.onEach {
            Log.e("ime here", "yes im here ${it}")
        }.launchIn(coroutineScope)
    }

I think viewModel.authMethod.collectAsState() is more convenient. But anyway, i do think this is what you can expect. Reobserving the stateflow will trigger the oneach, same as you would go back and forth between fragments and recreating the view also triggers the livedata observers. I think you should not observe on an event like that, perhaps you should create some sort of event stateflow that resets when the value has been read, or make the auth a part of the state of the screen.

So you don’t need to use both

rememberCoroutineScope

and

LaunchedEffect

- that’s redundant, use one or the other. The parameter to

LaunchedEffect

should be a thing that will cause the coroutine to restart if it changes (i.e. the data dependency of the coroutine). This could just be

LaunchedEffect(viewModel.authMethod) {
  viewModel.authMethod.collect {
    Log.e("ime here", "yes im here $it")
  }
}

I think it is triggered because it is restarted, as she wrote that it happens when navigating back and forth

That's correct joost it happens on the popBack Screen A prints message frist time Screen A does some network change on the viewModel and it triggers again the message (all good here) Then screen A pushes screen B Screen B popback and message is printed (this is the event I don't want to be teiggerd when screen B is popBack

how about doing something like this? https://github.com/mitchtabian/food2fork-compose/blob/d3ee84ecf5049ffdaf4e45a79716[…]h/food2forkcompose/presentation/ui/recipe/RecipeDetailScreen.kt

This looks like you want to hoist this responsibility into your viewmodel or similar. But with regard to the linked snippet above,