Scaffold

Scaffold implements the basic Material Design visual layout structure.

@Composable
fun Scaffold(
    contentWindowInsets: WindowInsets,
    modifier: Modifier = Modifier,
    scaffoldState: ScaffoldState = rememberScaffoldState(),
    topBar: @Composable () -> Unit = {},
    bottomBar: @Composable () -> Unit = {},
    snackbarHost: @Composable (SnackbarHostState) -> Unit = { SnackbarHost(it) },
    floatingActionButton: @Composable () -> Unit = {},
    floatingActionButtonPosition: FabPosition = FabPosition.End,
    isFloatingActionButtonDocked: Boolean = false,
    drawerContent: @Composable (ColumnScope.() -> Unit)? = null,
    drawerGesturesEnabled: Boolean = true,
    drawerShape: Shape = MaterialTheme.shapes.large,
    drawerElevation: Dp = DrawerDefaults.Elevation,
    drawerBackgroundColor: Color = MaterialTheme.colors.surface,
    drawerContentColor: Color = contentColorFor(drawerBackgroundColor),
    drawerScrimColor: Color = DrawerDefaults.scrimColor,
    backgroundColor: Color = MaterialTheme.colors.background,
    contentColor: Color = contentColorFor(backgroundColor),
    content: @Composable (PaddingValues) -> Unit,
)

Parameters

@Composable
fun Scaffold(
    modifier: Modifier = Modifier,
    scaffoldState: ScaffoldState = rememberScaffoldState(),
    topBar: @Composable () -> Unit = {},
    bottomBar: @Composable () -> Unit = {},
    snackbarHost: @Composable (SnackbarHostState) -> Unit = { SnackbarHost(it) },
    floatingActionButton: @Composable () -> Unit = {},
    floatingActionButtonPosition: FabPosition = FabPosition.End,
    isFloatingActionButtonDocked: Boolean = false,
    drawerContent: @Composable (ColumnScope.() -> Unit)? = null,
    drawerGesturesEnabled: Boolean = true,
    drawerShape: Shape = MaterialTheme.shapes.large,
    drawerElevation: Dp = DrawerDefaults.Elevation,
    drawerBackgroundColor: Color = MaterialTheme.colors.surface,
    drawerContentColor: Color = contentColorFor(drawerBackgroundColor),
    drawerScrimColor: Color = DrawerDefaults.scrimColor,
    backgroundColor: Color = MaterialTheme.colors.background,
    contentColor: Color = contentColorFor(backgroundColor),
    content: @Composable (PaddingValues) -> Unit,
)

Parameters

Code Examples

ScaffoldWithBottomBarAndCutout

@Composable
fun ScaffoldWithBottomBarAndCutout() {
    val scaffoldState = rememberScaffoldState()
    // Consider negative values to mean 'cut corner' and positive values to mean 'round corner'
    val sharpEdgePercent = -50f
    val roundEdgePercent = 45f
    // Start with sharp edges
    val animatedProgress = remember { Animatable(sharpEdgePercent) }
    // Create a coroutineScope for the animation
    val coroutineScope = rememberCoroutineScope()
    // animation value to animate shape
    val progress = animatedProgress.value.roundToInt()
    // When progress is 0, there is no modification to the edges so we are just drawing a rectangle.
    // This allows for a smooth transition between cut corners and round corners.
    val fabShape =
        if (progress < 0) {
            CutCornerShape(abs(progress))
        } else if (progress == roundEdgePercent.toInt()) {
            CircleShape
        } else {
            RoundedCornerShape(progress)
        }
    // lambda to call to trigger shape animation
    val changeShape: () -> Unit = {
        val target = animatedProgress.targetValue
        val nextTarget = if (target == roundEdgePercent) sharpEdgePercent else roundEdgePercent
        coroutineScope.launch {
            animatedProgress.animateTo(
                targetValue = nextTarget,
                animationSpec = TweenSpec(durationMillis = 600),
            )
        }
    }
    Scaffold(
        scaffoldState = scaffoldState,
        drawerContent = { Text("Drawer content") },
        topBar = { TopAppBar(title = { Text("Scaffold with bottom cutout") }) },
        bottomBar = {
            BottomAppBar(cutoutShape = fabShape) {
                IconButton(
                    onClick = { coroutineScope.launch { scaffoldState.drawerState.open() } }
                ) {
                    Icon(Icons.Filled.Menu, contentDescription = "Localized description")
                }
            }
        },
        floatingActionButton = {
            ExtendedFloatingActionButton(
                text = { Text("Change shape") },
                onClick = changeShape,
                shape = fabShape,
            )
        },
        contentWindowInsets = ScaffoldDefaults.contentWindowInsets,
        floatingActionButtonPosition = FabPosition.Center,
        isFloatingActionButtonDocked = true,
        content = { innerPadding ->
            LazyColumn(contentPadding = innerPadding) {
                items(count = 100) {
                    Box(Modifier.fillMaxWidth().height(50.dp).background(colors[it % colors.size]))
                }
            }
        },
    )
}

ScaffoldWithSimpleSnackbar

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

SimpleScaffoldWithTopBar

@Composable
fun SimpleScaffoldWithTopBar() {
    val scaffoldState = rememberScaffoldState()
    val scope = rememberCoroutineScope()
    Scaffold(
        scaffoldState = scaffoldState,
        drawerContent = { Text("Drawer content") },
        topBar = {
            TopAppBar(
                title = { Text("Simple Scaffold Screen") },
                navigationIcon = {
                    IconButton(onClick = { scope.launch { scaffoldState.drawerState.open() } }) {
                        Icon(Icons.Filled.Menu, contentDescription = "Localized description")
                    }
                },
            )
        },
        floatingActionButtonPosition = FabPosition.End,
        floatingActionButton = {
            ExtendedFloatingActionButton(
                text = { Text("Inc") },
                onClick = { /* fab click handler */ },
            )
        },
        contentWindowInsets = ScaffoldDefaults.contentWindowInsets,
        content = { innerPadding ->
            LazyColumn(contentPadding = innerPadding) {
                items(count = 100) {
                    Box(Modifier.fillMaxWidth().height(50.dp).background(colors[it % colors.size]))
                }
            }
        },
    )
}