Do you know how to keep the `LazyColumn` scroll st...

# compose

[nglauber]

Do you know how to keep the LazyColumn scroll state after navigate to a different screen? I’m getting a strange behavior…

val listState = rememberLazyListState()

val reportList by viewModel.reportList.flowInLifecycle()
    .collectAsState(initial = emptyList())

The code above is in ScreenA, from this screen I open ScreenB. When I return to ScreenA, the reportsList becomes empty for 1 composition, so the listState moves to position 0.

[Zach Klippenstein (he/him) [MOD]]

How is flowInLifecycle() defined? Assuming it’s a composable that correctly remembers the transformed flow, if viewModel.reportList is a StateFlow then flowInLifecycle should also return a StateFlow so that you can use the overload of collectAsState that takes its initial value from the actual flow.

[nglauber]

Good catch @Zach Klippenstein (he/him) [MOD]… I’ll check without it…. but here it is…

@Composable
fun <T> Flow<T>.flowInLifecycle(): Flow<T> {
    val lifecycleOwner = LocalLifecycleOwner.current
    return remember(this, lifecycleOwner) {
        this.flowWithLifecycle(lifecycleOwner.lifecycle, Lifecycle.State.STARTED)
    }
}

[JulianK]

I'm using a similar lifecycle aware flow collection, but for Stateflows, i use

@Composable
fun <T> StateFlow<T>.collectAndRemember(): State<T> =
    flowInLifecycle(this).collectAsState(initial = this.value)

[Zach Klippenstein (he/him) [MOD]]

Yea that collectAndRemember looks more like what i think you’d want

[nglauber]

@JulianK, could you post your flowInLifecycle?

[JulianK]

Should be the same as yours, actually, i changed the name to your method name in my previous comment.
My whole code looks like this:

@Composable
fun <T> rememberFlowWithLifecycle(
    flow: Flow<T>,
    lifecycle: Lifecycle = LocalLifecycleOwner.current.lifecycle,
    minActiveState: Lifecycle.State = Lifecycle.State.STARTED
): Flow<T> = remember(flow, lifecycle) {
    flow.flowWithLifecycle(
        lifecycle = lifecycle,
        minActiveState = minActiveState
    )
}


@Composable
fun <T> StateFlow<T>.collectAndRemember(): State<T> =
    rememberFlowWithLifecycle(this).collectAsState(initial = this.value)

[nglauber]

Awesome! Thanks 😉