Scaffold

Component in Material 3 Compose

Scaffold implements the basic material design visual layout structure.

This component provides API to put together several material components to construct your screen, by ensuring proper layout strategy for them and collecting necessary data so these components will work together correctly.

Simple example of a Scaffold with [SmallTopAppBar], [FloatingActionButton]:

@sample androidx.compose.material3.samples.SimpleScaffoldWithTopBar

To show a [Snackbar], use [SnackbarHostState.showSnackbar].

Last updated: 2024-10-22 13:47

Installation

dependencies {
   implementation("androidx.compose.material3:material3:1.4.0-alpha02")
}

Overloads

@Composable
fun Scaffold(
    modifier: Modifier = Modifier,
    topBar: @Composable () -> Unit = {},
    bottomBar: @Composable () -> Unit = {},
    snackbarHost: @Composable () -> Unit = {},
    floatingActionButton: @Composable () -> Unit = {},
    floatingActionButtonPosition: FabPosition = FabPosition.End,
    containerColor: Color = MaterialTheme.colorScheme.background,
    contentColor: Color = contentColorFor(containerColor),
    contentWindowInsets: WindowInsets = ScaffoldDefaults.contentWindowInsets,
    content: @Composable (PaddingValues) -> Unit
)

Parameters

name	description
modifier	the [Modifier] to be applied to this scaffold
topBar	top app bar of the screen, typically a [SmallTopAppBar]
bottomBar	bottom bar of the screen, typically a [NavigationBar]
snackbarHost	component to host [Snackbar]s that are pushed to be shown via [SnackbarHostState.showSnackbar], typically a [SnackbarHost]
floatingActionButton	Main action button of the screen, typically a [FloatingActionButton]
floatingActionButtonPosition	position of the FAB on the screen. See [FabPosition].
containerColor	the color used for the background of this scaffold. Use [Color.Transparent] to have no color.
contentColor	the preferred color for content inside this scaffold. Defaults to either the matching content color for [containerColor], or to the current [LocalContentColor] if [containerColor] is not a color from the theme.
contentWindowInsets	window insets to be passed to [content] slot via [PaddingValues] params. Scaffold will take the insets into account from the top/bottom only if the [topBar]/ [bottomBar] are not present, as the scaffold expect [topBar]/[bottomBar] to handle insets instead. Any insets consumed by other insets padding modifiers or [consumeWindowInsets] on a parent layout will be excluded from [contentWindowInsets].
content	content of the screen. The lambda receives a [PaddingValues] that should be applied to the content root via [Modifier.padding] and [Modifier.consumeWindowInsets] to properly offset top and bottom bars. If using [Modifier.verticalScroll], apply this modifier to the child of the scroll, and not on the scroll itself.

Code Examples

SimpleScaffoldWithTopBar

@OptIn(ExperimentalMaterial3Api::class)
@Preview
@Composable
fun SimpleScaffoldWithTopBar() {
    val colors =
        listOf(
            Color(0xFFffd7d7.toInt()),
            Color(0xFFffe9d6.toInt()),
            Color(0xFFfffbd0.toInt()),
            Color(0xFFe3ffd9.toInt()),
            Color(0xFFd0fff8.toInt())
        )

    Scaffold(
        topBar = {
            TopAppBar(
                title = { Text("Simple Scaffold Screen") },
                navigationIcon = {
                    IconButton(onClick = { /* "Open nav drawer" */ }) {
                        Icon(Icons.Filled.Menu, contentDescription = "Localized description")
                    }
                }
            )
        },
        floatingActionButtonPosition = FabPosition.End,
        floatingActionButton = {
            ExtendedFloatingActionButton(onClick = { /* fab click handler */ }) { Text("Inc") }
        },
        content = { innerPadding ->
            LazyColumn(
                // consume insets as scaffold doesn't do it by default
                modifier = Modifier.consumeWindowInsets(innerPadding),
                contentPadding = innerPadding
            ) {
                items(count = 100) {
                    Box(Modifier.fillMaxWidth().height(50.dp).background(colors[it % colors.size]))
                }
            }
        }
    )
}

ScaffoldWithSimpleSnackbar

@Preview
@Composable
fun ScaffoldWithSimpleSnackbar() {
    val snackbarHostState = remember { SnackbarHostState() }
    val scope = rememberCoroutineScope()
    Scaffold(
        snackbarHost = { SnackbarHost(snackbarHostState) },
        floatingActionButton = {
            var clickCount by remember { mutableStateOf(0) }
            ExtendedFloatingActionButton(
                onClick = {
                    // show snackbar as a suspend function
                    scope.launch { snackbarHostState.showSnackbar("Snackbar # ${++clickCount}") }
                }
            ) {
                Text("Show snackbar")
            }
        },
        content = { innerPadding ->
            Text(
                text = "Body content",
                modifier = Modifier.padding(innerPadding).fillMaxSize().wrapContentSize()
            )
        }
    )
}