Guys how do you manage state using flow? I have he...

# android

[Novo Dimaporo]

Guys how do you manage state using flow? I have here my code, but I am not confident about this.

private val loadTrigger = MutableSharedFlow<Long>()
    private var tState = TransactionsState()

    @OptIn(ExperimentalCoroutinesApi::class)
    val transactionsState = combine(
        currentUser.filterNotNull(),
        loadTrigger.onStart { emit(0) }
    ) { user, delayDuration -> user to delayDuration }
        .filterNot { tState.isLoading }
        .onEach { tState = tState.copy(loadingPage = tState.page + 1, isLoading = true) }
        .flatMapLatest { (user, delayDuration) ->
            delay(delayDuration)
            observeTransactionDetails(
                count = tState.loadingPage * PAGE_SIZE,
                userId = user.uid,
                accountId = accountId)
        }
        .map { result ->
            tState.copy(
                transactions = TransactionProcessor
                    .toListItems(result),
                page = tState.loadingPage,
                isEndOfList = result.isEmpty(),
                isLoading = false
            )
        }
        .onEach { tState = it }
        .stateIn(
            scope = viewModelScope,
            started = SharingStarted.Eagerly,
            initialValue = TransactionsState()
        )

    fun loadNext() {
        viewModelScope.launch { loadTrigger.emit(500) }
    }

I tried using runningFold at first, but I need to have access to the current state to debounce the request to load more if it is still loading a page.

I did not use paging 3 because I am working on a KMM project.

Let me know if you need more context to understand this snippet.

[Chrimaeon]

@statmark56, @Yves Kalume , @Pavel Haluza and @olanre12waju, your time to shine - help your fellow Android dev. This is a not not kotlin but kotlin colored post now. 😉

[Ujjwal Sai]

You're managing state using Flow quite well, but relying on tState as a mutable variable outside the flow chain can lead to subtle issues — especially with rapid emissions or concurrency.
A more idiomatic approach would be to keep state within the flow itself, using something like runningFold or scan, which gives you access to the previous state and emits the new one reactively.
This way, you can handle isLoading, page, and transactions updates in a clean, reactive way without needing to manually track tState.

[Novo Dimaporo]

Hi @Ujjwal Sai thanks for the respond. The problem with sacn or runningfold is that I cant use the isLoading field of the state because the state is only inside this operator and to the collector, I need isLoading to block the succeeding request to load more items. I was eyeing if I can use CONFLATED channel.

[Novo Dimaporo]

Or maybe I will just give-up reactive for now. It is a little hard to handle, and maybe lacks some operator. I used RxJava before and I think my experience was better because of operators like Publish, typeOf, Merge, etc.

[Chrimaeon]

Please don’t sent your answers to the main channel.

[Ujjwal Sai]

Sure

[Novo Dimaporo]

oh, sorry. Sure!