IssueTracker

Project: platform/frameworks/support
Branch: androidx-main
Author: Louis Pullen-Freilich <lpf@google.com>
Link:      https://android-review.googlesource.com/3328184

Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling

Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling 
 
These APIs allow overscroll to have events dispatched to it by one component, and rendered in a separate component. 
 
Fixes: b/266550551 
Fixes: b/204650733 
Fixes: b/255554340 
Fixes: b/229537244 
Test: OverscrollTest 
Relnote: "Adds OverscrollEffect#withoutDrawing and OverscrollEffect#withoutEventHandling APIs - these APIs create a wrapped instance of the provided overscroll effect that doesn't draw / handle events respectively, which allows for rendering  overscroll in a separate component from the component that is dispatching events. For example, disabling drawing the overscroll inside a lazy list, and then drawing the overscroll separately on top / elsewhere." 
Change-Id: Idbb3d91546b49c1987a041f959bce4b2b09a9f61

The following release(s) address this bug.It is possible this bug has only been partially addressed:

• androidx.compose.foundation:foundation:1.8.0-alpha06
• androidx.compose.foundation:foundation-android:1.8.0-alpha06
• androidx.compose.foundation:foundation-jvmstubs:1.8.0-alpha06
• androidx.compose.foundation:foundation-linuxx64stubs:1.8.0-alpha06

We're facing the same issue with TopAppBar and TopAppBarDefaults.pinnedScrollBehavior. When scrolling quickly on a lazy layout, the app bar container color does not respond.

Repo: https://github.com/smelfungus/NestedScrollAppBarIssue/tree/master

Video: https://drive.google.com/file/d/1XmJENXecUYq0hAC2xGBvrr2k_XeeXvZe/view?usp=sharing

val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior()

Scaffold(
    modifier = Modifier
        .fillMaxSize()
        .nestedScroll(scrollBehavior.nestedScrollConnection),
    topBar = {
        TopAppBar(
            title = {
                Text(
                    modifier = Modifier.fillMaxWidth(),
                    text = "Hello!",
                    textAlign = TextAlign.Center,
                )
            },
            scrollBehavior = scrollBehavior,
        )
    },
) { innerPadding ->
    LazyColumn(
        modifier = Modifier.padding(innerPadding),
        contentPadding = PaddingValues(16.dp),
        verticalArrangement = Arrangement.spacedBy(8.dp),
    ) {
        items(100) {
            Text(
                text = "Item $it",
                modifier = Modifier
                    .fillMaxWidth()
                    .background(MaterialTheme.colorScheme.surfaceContainerHigh)
                    .padding(24.dp),
            )
        }
    }
}

I am facing the same bug and i think the root case for it is that the PinnedScrollBehavior doesn't override the onPostFling in its NestedScrollConnection implementation.

I made a crude simple custom version and added

override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
    if (available.y > Velocity.Zero.y)
        state.contentOffset = 0f

    return super.onPostFling(consumed, available)
}

and then it works fine for me!

Project: platform/frameworks/support
Branch: androidx-main
Author: Shalom Gibly <sgibly@google.com>
Link:      https://android-review.googlesource.com/3375689

Fix the app-bars behaviors to detect end of scroll

Fix the app-bars behaviors to detect end of scroll 
 
Apply a fix to all the behaviors to detect the end of scroll in the post 
fling function. This will better ensure an app-bar color change when the 
content is scrolled all the way. 
 
Bug: 293665988 
Test: Manual 
Relnote: "Fix the top and bottom app-bar behaviors to reliably change 
color when content is scrolled all the way." 
 
Change-Id: Idc4e834695cbd7cb8099f7b63cf21d5b764f1c81