Jetpack Compose collapsing toolbar

Jetpack Compose implementation of Material Design 3 includes 4 types of Top App Bars (https://m3.material.io/components/top-app-bar/implementation):

• CenterAlignedTopAppBar
• SmallTopAppBar
• MediumTopAppBar
• LargeTopAppBar

https://developer.android.com/reference/kotlin/androidx/compose/material3/package-summary

They all have a scrollBehavior parameter, which can be used for collapsing the toolbar. There are 3 basic types of scroll behavior in the library:

• TopAppBarDefaults.pinnedScrollBehavior
• TopAppBarDefaults.enterAlwaysScrollBehavior
• TopAppBarDefaults.exitUntilCollapsedScrollBehavior

https://developer.android.com/reference/kotlin/androidx/compose/material3/TopAppBarDefaults

Note: This API is annotated as experimental at the moment.

Sample usage:

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun Test() {
    val scrollBehavior = TopAppBarDefaults.enterAlwaysScrollBehavior(rememberTopAppBarState())
    Scaffold(
        modifier = Modifier.nestedScroll(scrollBehavior.nestedScrollConnection),
        topBar = {
            MediumTopAppBar(
                title = { Text(text = "Scroll Behavior Test") },
                navigationIcon = {
                    IconButton(onClick = { /*TODO*/ }) {
                        Icon(imageVector = Icons.Default.Menu, contentDescription = "")
                    }
                },
                scrollBehavior = scrollBehavior
            )
        }
    ) {
        LazyColumn(modifier = Modifier.fillMaxWidth()) {
            items((1..50).toList()) { item ->
                Text(modifier = Modifier.padding(8.dp), text = "Item $item")
            }
        }
    }
}