BottomAppBar

Component in Material Compose

A bottom app bar displays navigation and key actions at the bottom of screens.

Last updated: 2024-10-22 13:47

Installation

dependencies {
   implementation("androidx.compose.material:material:1.8.0-alpha04")
}

Overloads

@Composable
fun BottomAppBar(
    windowInsets: WindowInsets,
    modifier: Modifier = Modifier,
    backgroundColor: Color = MaterialTheme.colors.primarySurface,
    contentColor: Color = contentColorFor(backgroundColor),
    cutoutShape: Shape? = null,
    elevation: Dp = AppBarDefaults.BottomAppBarElevation,
    contentPadding: PaddingValues = AppBarDefaults.ContentPadding,
    content: @Composable RowScope.() -> Unit
)

Parameters

name	description
windowInsets	a window insets that app bar will respect.
modifier	The [Modifier] to be applied to this BottomAppBar
backgroundColor	The background color for the BottomAppBar. Use [Color.Transparent] to have no color.
contentColor	The preferred content color provided by this BottomAppBar to its children. Defaults to either the matching content color for [backgroundColor], or if [backgroundColor] is not a color from the theme, this will keep the same value set above this BottomAppBar.
cutoutShape	the shape of the cutout that will be added to the BottomAppBar - this should typically be the same shape used inside the [FloatingActionButton], when [BottomAppBar] and [FloatingActionButton] are being used together in [Scaffold]. This shape will be drawn with an offset around all sides. If null, where will be no cutout.
elevation	the elevation of this BottomAppBar.
contentPadding	the padding applied to the content of this BottomAppBar
content	the content of this BottomAppBar. The default layout here is a [Row], so content inside will be placed horizontally.

@Composable
fun BottomAppBar(
    modifier: Modifier = Modifier,
    backgroundColor: Color = MaterialTheme.colors.primarySurface,
    contentColor: Color = contentColorFor(backgroundColor),
    cutoutShape: Shape? = null,
    elevation: Dp = AppBarDefaults.BottomAppBarElevation,
    contentPadding: PaddingValues = AppBarDefaults.ContentPadding,
    content: @Composable RowScope.() -> Unit
)

Parameters

name	description
modifier	The [Modifier] to be applied to this BottomAppBar
backgroundColor	The background color for the BottomAppBar. Use [Color.Transparent] to have no color.
contentColor	The preferred content color provided by this BottomAppBar to its children. Defaults to either the matching content color for [backgroundColor], or if [backgroundColor] is not a color from the theme, this will keep the same value set above this BottomAppBar.
cutoutShape	the shape of the cutout that will be added to the BottomAppBar - this should typically be the same shape used inside the [FloatingActionButton], when [BottomAppBar] and [FloatingActionButton] are being used together in [Scaffold]. This shape will be drawn with an offset around all sides. If null, where will be no cutout.
elevation	the elevation of this BottomAppBar.
contentPadding	the padding applied to the content of this BottomAppBar
content	the content of this BottomAppBar. The default layout here is a [Row], so content inside will be placed horizontally.

Code Example

SimpleBottomAppBar

@Composable
fun SimpleBottomAppBar() {
    BottomAppBar(windowInsets = AppBarDefaults.bottomAppBarWindowInsets) {
        // Leading icons should typically have a high content alpha
        CompositionLocalProvider(LocalContentAlpha provides ContentAlpha.high) {
            IconButton(onClick = { /* doSomething() */ }) {
                Icon(Icons.Filled.Menu, contentDescription = "Localized description")
            }
        }
        // The actions should be at the end of the BottomAppBar. They use the default medium
        // content alpha provided by BottomAppBar
        Spacer(Modifier.weight(1f, true))
        IconButton(onClick = { /* doSomething() */ }) {
            Icon(Icons.Filled.Favorite, contentDescription = "Localized description")
        }
        IconButton(onClick = { /* doSomething() */ }) {
            Icon(Icons.Filled.Favorite, contentDescription = "Localized description")
        }
    }
}