about `#AndroidDevChallenge` … My github actions f...

# compose

[Sinan Gunes]

about #AndroidDevChallenge … My github actions fails on this test:

com.example.androiddevchallenge.ExampleInstrumentedTest > sampleTest[test(AVD) - 10] FAILED 
254
	kotlin.UninitializedPropertyAccessException: lateinit property remeasurement has not been initialized
255
	at androidx.compose.foundation.lazy.LazyListState.snapToItemIndexInternal$foundation_release(LazyListState.kt:186)

I haven’t touch that part. Any of you faced similar?

[Andrey Kulikov]

snapToItemIndex seems to be called before measuring finished. from where do you call it?

[Sinan Gunes]

roughly this is it:

Box() {
        val scrollState = rememberLazyListState()
        LazyRow(state = scrollState) {
            items(1000) {
                Text(text = text(it))
            }
        }

        scope.launch {
            scrollState.scrollToItem(index, scroll)
        }
    }

[Andrey Kulikov]

running coroutine right from the composable is never what you want. composable can be recomposed multiple times and then your task will be run again on every recomposition

[Andrey Kulikov]

you basically want to set an initial scroll position, right? the correct way to do it is by passing them as a params to rememberLazyListState() function

[Shivam Sethi]

So how we can achieve the same behaviour where we have to do some suspend task with the preferred way?

[BenjO]

Yes, that's what I have in mind. I don't know how the rule would be enforced, but if the answer is never use launch, maybe there is a thing to automate.

[Sinan Gunes]

@Andrey Kulikov what I want is, when item\scroll changes scroll the view accordingly. not just initially. item\scroll is calculated through a mutable state.

[Albert Chang]

@Shivam Sethi Use LaunchedEffect.

[Sinan Gunes]

also used that, did not saw a noticable effect on my use.

[Andrey Kulikov]

we already working on such lint rule https://android-review.googlesource.com/c/platform/frameworks/support/+/1621389

[Andrey Kulikov]

val scrollState = key(index, scroll) { rememberLazyListState(index, scroll) }
        LazyRow(state = scrollState)

[Andrey Kulikov]

maybe something like this will work for you?

[Sinan Gunes]

hey, this is actually great. and this is how I collected scroll changes as well:

LaunchedEffect(scrollState) {
            snapshotFlow { scrollState.firstVisibleItemIndex + (scrollState.firstVisibleItemScrollOffset / cellWidthPx).roundToInt() }
                .distinctUntilChanged()
                .filterNot { counting }
                .onEach {
                    onScrolled(it)
                }
                .collect()
        }

[Sinan Gunes]

amazing… thanks 👍🏻