Scaffold
Component in Material 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.
For similar components that implement different layout structures, see [BackdropScaffold], which uses a backdrop as the centerpiece of the screen, and [BottomSheetScaffold], which uses a persistent bottom sheet as the centerpiece of the screen.
This particular overload provides ability to specify [WindowInsets]. Recommended value can be found in [ScaffoldDefaults.contentWindowInsets].
Simple example of a Scaffold with [TopAppBar], [FloatingActionButton] and drawer:
@sample androidx.compose.material.samples.SimpleScaffoldWithTopBar
More fancy usage with [BottomAppBar] with cutout and docked [FloatingActionButton], which animates it's shape when clicked:
@sample androidx.compose.material.samples.ScaffoldWithBottomBarAndCutout
To show a [Snackbar], use [SnackbarHostState.showSnackbar]. Scaffold state already have [ScaffoldState.snackbarHostState] when created
Last updated:
Installation
dependencies {
implementation("androidx.compose.material:material:1.8.0-alpha04")
}
Overloads
@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
name | description |
---|---|
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]. |
modifier | optional Modifier for the root of the [Scaffold] |
scaffoldState | state of this scaffold widget. It contains the state of the screen, e.g. variables to provide manual control over the drawer behavior, sizes of components, etc |
topBar | top app bar of the screen. Consider using [TopAppBar]. |
bottomBar | bottom bar of the screen. Consider using [BottomAppBar]. |
snackbarHost | component to host [Snackbar]s that are pushed to be shown via [SnackbarHostState.showSnackbar]. Usually it's a [SnackbarHost] |
floatingActionButton | Main action button of your screen. Consider using [FloatingActionButton] for this slot. |
floatingActionButtonPosition | position of the FAB on the screen. See [FabPosition] for possible options available. |
isFloatingActionButtonDocked | whether [floatingActionButton] should overlap with [bottomBar] for half a height, if [bottomBar] exists. Ignored if there's no [bottomBar] or no [floatingActionButton]. |
drawerContent | content of the Drawer sheet that can be pulled from the left side (right for RTL). |
drawerGesturesEnabled | whether or not drawer (if set) can be interacted with via gestures |
drawerShape | shape of the drawer sheet (if set) |
drawerElevation | drawer sheet elevation. This controls the size of the shadow below the drawer sheet (if set) |
drawerBackgroundColor | background color to be used for the drawer sheet |
drawerContentColor | color of the content to use inside the drawer sheet. Defaults to either the matching content color for [drawerBackgroundColor], or, if it is not a color from the theme, this will keep the same value set above this Surface. |
drawerScrimColor | color of the scrim that obscures content when the drawer is open |
backgroundColor | background of the scaffold body |
contentColor | color of the content in scaffold body. Defaults to either the matching content color for [backgroundColor], or, if it is not a color from the theme, this will keep the same value set above this Surface. |
content | content of your screen. The lambda receives an [PaddingValues] that should be applied to the content root via Modifier.padding to properly offset top and bottom bars. If you're using VerticalScroller, apply this modifier to the child of the scroller, and not on the scroller itself. |
@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
name | description |
---|---|
modifier | optional Modifier for the root of the [Scaffold] |
scaffoldState | state of this scaffold widget. It contains the state of the screen, e.g. variables to provide manual control over the drawer behavior, sizes of components, etc |
topBar | top app bar of the screen. Consider using [TopAppBar]. |
bottomBar | bottom bar of the screen. Consider using [BottomAppBar]. |
snackbarHost | component to host [Snackbar]s that are pushed to be shown via [SnackbarHostState.showSnackbar]. Usually it's a [SnackbarHost] |
floatingActionButton | Main action button of your screen. Consider using [FloatingActionButton] for this slot. |
floatingActionButtonPosition | position of the FAB on the screen. See [FabPosition] for possible options available. |
isFloatingActionButtonDocked | whether [floatingActionButton] should overlap with [bottomBar] for half a height, if [bottomBar] exists. Ignored if there's no [bottomBar] or no [floatingActionButton]. |
drawerContent | content of the Drawer sheet that can be pulled from the left side (right for RTL). |
drawerGesturesEnabled | whether or not drawer (if set) can be interacted with via gestures |
drawerShape | shape of the drawer sheet (if set) |
drawerElevation | drawer sheet elevation. This controls the size of the shadow below the drawer sheet (if set) |
drawerBackgroundColor | background color to be used for the drawer sheet |
drawerContentColor | color of the content to use inside the drawer sheet. Defaults to either the matching content color for [drawerBackgroundColor], or, if it is not a color from the theme, this will keep the same value set above this Surface. |
drawerScrimColor | color of the scrim that obscures content when the drawer is open |
backgroundColor | background of the scaffold body |
contentColor | color of the content in scaffold body. Defaults to either the matching content color for [backgroundColor], or, if it is not a color from the theme, this will keep the same value set above this Surface. |
content | content of your screen. The lambda receives an [PaddingValues] that should be applied to the content root via Modifier.padding to properly offset top and bottom bars. If you're using VerticalScroller, apply this modifier to the child of the scroller, and not on the scroller itself. |
Code Examples
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]))
}
}
}
)
}
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()
)
}
)
}