I am experiencing some weird behaviour with Accompanist Pager v0.19.0 (after it’s adjustment to use ...

# compose

[Stylianos Gakis]

I am experiencing some weird behaviour with Accompanist Pager v0.19.0 (after it’s adjustment to use LazyX under the hood). More details in the thread🧵

[Stylianos Gakis]

Screen_Recording_20211014-144502_Hedvig Dev.mp4

[Stylianos Gakis]

The above video showcases it. The fling behaviour (and the indicators by extension) don’t really settle where they should.
Not sure if this is happening due to me adding a bigger contentPadding horizontally than I do itemSpacing between the items. But this is the behaviour I am looking to achieve, I want the items to purposefully take less screen space than they need so that the next item also shows, indicating that there’s more items to see.
Has someone experienced this as well? Does it feel like a problem that exists in the Pager itself or something I am messing up somehow? Any way to tell?

[Stylianos Gakis]

Code looks like this:

val claimStatusDataList: List<ClaimStatusData> = ...
val pagerState = rememberPagerState()
Column {
    HorizontalPager(
        count = claimStatusDataList.size,
        key = { page: Int -> claimStatusDataList[page].id },
        state = pagerState,
        itemSpacing = 16.dp,
        contentPadding = PaddingValues(horizontal = 12.dp),
    ) { page: Int ->
        val claimStatusData = claimStatusDataList[page]
        ClaimStatusCard(
            claimStatusData = claimStatusData,
        )
    }

    Spacer(Modifier.height(16.dp))

    HorizontalPagerIndicator(
        pagerState = pagerState,
        modifier = Modifier.align(Alignment.CenterHorizontally)
    )
}

With ClaimStatusCard being that card item you’re looking at. Not sure if that composable’s internals are important or not.

[Stylianos Gakis]

When having both itemSpacing contentPadding be 0.dp, it seems to always work.

When itemSpacing is 0 and contentPadding is non-zero, it works just fine too.

When itemSpacing is non-zero and contentPadding is 0, it stops working, getting this weird behaviour that doesn’t settle properly in the centre of the item again.

[Lucien Guimaraes]

I just upgraded to Accompanist 0.19.0, and I have the same weird behaviour. And it's super inconsistent, sometimes it's always visible, sometimes not 🤔

[Andrey Kulikov]

seems like itemSpacing is incorrectly handled, please file a bug in Accompanist repo

[Stylianos Gakis]

Okay, I shall do that!

[Andrey Kulikov]

I think you should be able to workaround it if you add an item spacing as Modifier.padding(end = 16.dp) directly on ClaimStatusCard() for all but last pages

[Stylianos Gakis]

That’s exactly what I am doing for now:

val extraPadding = PaddingValues(
    start = if (page == 0) { 0.dp } else { 6.dp },
    end = if (page == claimStatusDataList.lastIndex) { 0.dp } else { 6.dp },
)

to “fake” a 12.dp spacing between them.
Your approach should work too, but I want the item to look centred when it’s the one selected, I’m guessing adding only an end padding would make it look a bit off.
I am in the process of writing the bug report now. Is it ok if I add a link to this discussion as well? This isn’t a public channel that’s why I wonder.

[Andrey Kulikov]

sure, that is fine

[Stylianos Gakis]

Linking here for future reference: https://github.com/google/accompanist/issues/793