I have this code, which makes an api call But it does not get called, neither breakpoints are trigge...

# compose

[Vaibhav Jaiswal]

I have this code, which makes an api call
But it does not get called, neither breakpoints are triggered nor anything is being logged

LaunchedEffect(listState){
        snapshotFlow { listState.layoutInfo }
            .map { it.visibleItemsInfo }
            .map { items -> items.map { news[it.index] } }
            .onEach { it.log("Recording Viewed") }
            .map { it.filterNotNull() }
            .safeCatch()
            .collect { it.onEach(component::recordViewed) }
    }

here news is a LazyPagingItems<T>

[Vaibhav Jaiswal]

Sometimes it is logged but with emptyList

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

That looks fine to me. Can you post more surrounding code?

[Vaibhav Jaiswal]

This is my whole component @Zach Klippenstein (he/him) [MOD]

@Composable
fun NewsTab(
    component: NewsTabComponent,
    bottomNavVisibility:(Boolean) -> Unit
) {
    val news = component.newsFeed.collectAsLazyPagingItems()
    val listState = rememberLazyListState()

    LaunchedEffect(component){
        component.onTabReselected
            .onEach { listState.fastScrollToTop() }
            .safeCatch()
            .launchIn(this)
    }

    val isScrollingUp = listState.isScrollingUp()
    bottomNavVisibility(isScrollingUp)

    BaseScreenContent(
        component = component,
        onRefresh = { component.withSwipeRefresh { news.refresh() }},
    ){
        MedialLazyColumn(
            modifier = Modifier.fillMaxSize(),
            state = listState,
            loadState = news.loadState.mediator,
            items = news,
            contentType = { this.type },
            loader = remember { { item { Loader(Modifier.fillParentMaxSize()) } } }
        ) {
            when (it) {
                is NewsMedia.News -> NewsCard(it, Modifier.fillMaxWidth(), onAction = component::handleAction)
                is NewsMedia.Poll -> PollCard(it, Modifier.fillMaxWidth(), onAction = component::handleAction)
                is NewsMedia.Quiz -> QuizCard(it, Modifier.fillMaxWidth(), onAction = component::handleAction)
            }

        }
    }

    LaunchedEffect(listState){
        snapshotFlow { listState.layoutInfo }
            .map { it.visibleItemsInfo }
            .map { items -> items.map { news.peek(it.index) } }
            .onEach { it.log("Recording Viewed") }
            .map { it.filterNotNull() }
            .safeCatch()
            .collect { it.onEach(component::recordViewed) }
    }

}

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

Yea that looks fine. I’m not sure why nothing is getting logged. What if you put a log statement inside the snapshotFlow lambda itself and spit out something about the visible items, are you seeing anything then?

[Vaibhav Jaiswal]

Nothing is being logged, breakpoint is not triggered

[Vaibhav Jaiswal]

@Zach Klippenstein (he/him) [MOD] this seems to get called only the initial time, the list is drawn on screen and not again when list is being scrolled

[Vaibhav Jaiswal]

Changing it to this fixed it

LaunchedEffect(listState){
        snapshotFlow { listState.isScrollInProgress }
            .filterNot { it }
            .map { listState.layoutInfo.visibleItemsInfo.map { news.peek(it.index) } }
            .map { it.filterNotNull() }
            .safeCatch()
            .onEach { it.onEach(component::recordViewed) }
            .launchIn(this)
    }

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

what is safeCatch? Is that catching some exception that is cancelling the flow?

[Vaibhav Jaiswal]

It catches all exceptions except CancellationException

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

So, was it catching some exception that was terminating the flow early?

[Vaibhav Jaiswal]

No, I added a breakpoint there
Did not hit

When i made the change I sent above, it starting working perfectly