Desktop: Nested scrolling is not working properly

[tchernykh]

NestedScrollConnectionSample from compose samples (link) is not working on desktop - toolbar suppose to move away when scrolling. Here in the sample onPreScroll method is never called. The sample works fine when run on Android.

@Composable
fun NestedScrollConnectionSample() {
    // here we use LazyColumn that has build-in nested scroll, but we want to act like a
    // parent for this LazyColumn and participate in its nested scroll.
    // Let's make a collapsing toolbar for LazyColumn
    val toolbarHeight = 48.dp
    val toolbarHeightPx = with(LocalDensity.current) { toolbarHeight.roundToPx().toFloat() }
    // our offset to collapse toolbar
    val toolbarOffsetHeightPx = remember { mutableStateOf(0f) }
    // now, let's create connection to the nested scroll system and listen to the scroll
    // happening inside child LazyColumn
    val nestedScrollConnection = remember {
        object : NestedScrollConnection {
            override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
                // try to consume before LazyColumn to collapse toolbar if needed, hence pre-scroll
                val delta = available.y
                val newOffset = toolbarOffsetHeightPx.value + delta
                toolbarOffsetHeightPx.value = newOffset.coerceIn(-toolbarHeightPx, 0f)
                // here's the catch: let's pretend we consumed 0 in any case, since we want
                // LazyColumn to scroll anyway for good UX
                // We're basically watching scroll without taking it
                return Offset.Zero
            }
        }
    }
    Box(
        Modifier
            .fillMaxSize()
            // attach as a parent to the nested scroll system
            .nestedScroll(nestedScrollConnection)
    ) {
        // our list with build in nested scroll support that will notify us about its scroll
        LazyColumn(contentPadding = PaddingValues(top = toolbarHeight)) {
            items(100) { index ->
                Text("I'm item $index", modifier = Modifier.fillMaxWidth().padding(16.dp))
            }
        }
        TopAppBar(
            modifier = Modifier
                .height(toolbarHeight)
                .offset { IntOffset(x = 0, y = toolbarOffsetHeightPx.value.roundToInt()) },
            title = { Text("toolbar offset is ${toolbarOffsetHeightPx.value}") }
        )
    }
}

Library version: 0.4.0-build182
OS: MacOS

[kyori19]

Any updates on this issue?

[HuixingWong]

Any updates on this issue?

[HuixingWong]

@akurasov hello any plan for this issue?

[akurasov]

There are no specific plans about it yet

[Thomas-Vos]

Could this please be fixed?

[Thomas-Vos]

Are there any workarounds for this issue?

[christiandeange]

Still no movement on this? It's been almost 2 years with no progress. Pull Refresh APIs are being introduced that rely on nested scroll, rendering them unusable on Desktop platforms.

[MessiasLima]

Any update on this? It makes TopAppBarDefaults.exitUntilCollapsedScrollBehavior() unusable in desktops, right?

[jerryion]

Does Compose desktop supports Scafford + TopAppBar nested scroll&collapsed effect? I try to make it in compose desktop but the app bar didn’t collapse as Android side when I scrolled the content.

[archiegq21]

Did you guys found any workaround?

[GazimSoliev]

This bug still exists

[MatkovIvan]

It was fixed in 1.6.0 branch, but we didn't merge this from upstream yet

[456634]

It was fixed in 1.6.0 branch, but we didn't merge this from upstream yet

Unfortunately, it's still not fixed in version 1.6.0-dev1405 and 1.6.0-beta01.

[MatkovIvan]

True, I've already checked this after the merge of Google's fix, but it seems that it requires changes from the multiplatform side too. I'll try to fix it before our 1.6 release, but no promises at the moment

UPD: it does NOT included in 1.6.0