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Bottom app bars

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

Purple bottom app bar with floating action button

Note: This doc reflects the Bottom App Bar after the changes in 1.7 to reflect the current M3 style. Use Widget.Material3.BottomAppBar.Legacy to revert back to the previous style.

Contents

Using bottom app bars

Before you can use Material bottom app bars, you need to add a dependency to the Material Components for Android library. For more information, go to the Getting started page.

Making bottom app bars accessible

Android's bottom app bar component APIs provide support for the navigation icon, action items, overflow menu and more to tell the user what each action performs. While optional, their use is strongly encouraged.

Content descriptions

When using navigation icons, action items and other elements of bottom app bars, you should set a content description for them so that screen readers like TalkBack are able to announce their purpose or action.

For an overall content description of the bottom app bar, set an android:contentDescription or use the setContentDescription method on the BottomAppBar.

For the navigation icon, use the app:navigationContentDescription attribute or setNavigationContentDescription method.

For action items and items within the overflow menu, set the content description in the menu:

<menu ...>
    ...
    <item
          ...
          android:contentDescription="@string/content_description_one" />
    <item
          ...
          android:contentDescription="@string/content_description_two" />
</menu>

Bottom app bar

Bottom app bars provide access to a bottom navigation drawer and up to four actions, including the floating action button.

Bottom app bar examples

API and source code:

The following example shows a bottom app bar with a navigation icon, 3 action icons, and an embedded FAB.

Purple bottom app bar with grey icons and purple inset floating action button

In the layout:

<androidx.coordinatorlayout.widget.CoordinatorLayout
    ...
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- Note: A RecyclerView can also be used -->
    <androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="100dp"
        android:clipToPadding="false">

        <!-- Scrollable content -->

    </androidx.core.widget.NestedScrollView>

    <com.google.android.material.bottomappbar.BottomAppBar
        android:id="@+id/bottomAppBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        style="@style/Widget.Material3.BottomAppBar"
        app:navigationIcon="@drawable/ic_drawer_menu_24px"
        app:menu="@menu/bottom_app_bar"
        />

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/ic_add_24dp"
        app:layout_anchor="@id/bottomAppBar"
        />

</androidx.coordinatorlayout.widget.CoordinatorLayout>

In menu/bottom_app_bar.xml:

<menu
      ...>
    <item
      android:id="@+id/accelerator"
      android:icon="@drawable/ic_accelerator_24px"
      android:title="@string/accelerator"
      android:contentDescription="@string/content_description_accelerator"
      app:showAsAction="ifRoom"/>

    <item
      android:id="@+id/rotation"
      android:icon="@drawable/ic_3d_rotation_24px"
      android:title="@string/rotation"
      android:contentDescription="@string/content_description_rotation"
      app:showAsAction="ifRoom"/>

    <item
      android:id="@+id/dashboard"
      android:icon="@drawable/ic_dashboard_24px"
      android:title="@string/dashboard"
      android:contentDescription="@string/content_description_dashboard"
      app:showAsAction="ifRoom"/>

</menu>

In menu/navigation icon drawables:

<vector
    ...
    android:tint="?attr/colorControlNormal">
    ...
</vector>

In code:

bottomAppBar.setNavigationOnClickListener {
    // Handle navigation icon press
}

bottomAppBar.setOnMenuItemClickListener { menuItem ->
    when (menuItem.itemId) {
        R.id.accelerator -> {
            // Handle accelerator icon press
            true
        }
        R.id.rotation -> {
            // Handle rotation icon press
            true
        }
        R.id.dashboard -> {
            // Handle dashboard icon press
            true
        }
        else -> false
    }
}

Applying scrolling behavior to the bottom app bar

The following example shows the bottom app bar hiding when scrolling the scrollable content down, and appearing when scrolling up.

<androidx.coordinatorlayout.widget.CoordinatorLayout
    ...>

    ...

    <com.google.android.material.bottomappbar.BottomAppBar
        ...
        app:hideOnScroll="true"
        />

    ...

</androidx.coordinatorlayout.widget.CoordinatorLayout>

Anatomy and key properties

A bottom app bar has a container and an optional navigation icon, anchored floating action button (FAB), action item(s) and an overflow menu.

Bottom app bar anatomy diagram

  1. Container
  2. Floating action button (FAB) (optional)
  3. Action item(s) (optional)
  4. Navigation icon (optional)
  5. Overflow menu (optional)

Container attributes

Element Attribute Related method(s) Default value
Color app:backgroundTint setBackgroundTint
getBackgroundTint		 ?attr/colorSurface
Elevation app:elevation setElevation 3dp
Height android:minHeight setMinimumHeight
getMinimumHeight		 80dp
Shadows app:addElevationShadow N/A false

Navigation icon attributes

Element Attribute Related method(s) Default value
Icon app:navigationIcon setNavigationIcon
getNavigationIcon		 null
Color app:navigationIconTint setNavigationIconTint ?attr/colorOnSurfaceVariant (as Drawable tint)

FAB attributes

Element Attribute Related method(s) Default value
Alignment mode app:fabAlignmentMode setFabAlignmentMode
getFabAlignmentMode		 end
Animation mode app:fabAnimationMode setFabAnimationMode
getFabAnimationMode		 slide
Anchor mode app:fabAnchorMode setFabAnchorMode
getFabAnchorMode		 embed
Cradle margin app:fabCradleMargin setFabCradleMargin
getFabCradleMargin		 6dp
Cradle rounded corner radius app:fabCradleRoundedCornerRadius setFabCradleRoundedCornerRadius
getFabCradleRoundedCornerRadius		 4dp
Cradle vertical offset app:fabCradleVerticalOffset setCradleVerticalOffset
getCradleVerticalOffset		 12dp
End margin app:fabAlignmentModeEndMargin setFabAlignmentModeEndMargin
getFabAlignmentModeEndMargin		 16dp
Embedded elevation app:removeEmbeddedFabElevation N/A true

See the FAB documentation for more attributes.

Action item(s) attributes

Element Attribute Related method(s) Default value
Menu app:menu replaceMenu
getMenu		 null
Icon color N/A N/A ?attr/colorControlNormal (as Drawable tint)
Alignment mode app:menuAlignmentMode setMenuAlignmentMode
getMenuAlignmentMode		 start

Overflow menu attributes

Element Attribute Related method(s) Default value
Icon android:src and app:srcCompat in actionOverflowButtonStyle (in app theme) setOverflowIcon
getOverflowIcon		 @drawable/abc_ic_menu_overflow_material (before API 23) or @drawable/ic_menu_moreoverflow_material (after API 23)
Theme app:popupTheme setPopupTheme
getPopupTheme		 @style/ThemeOverlay.Material3.*
Item typography textAppearanceSmallPopupMenu and textAppearanceLargePopupMenu in app:popupTheme or app theme N/A ?attr/textAppearanceTitleMedium

Styles

Element Style
Default style Widget.Material3.BottomAppBar

Default style theme attribute: bottomAppBarStyle

See the full list of styles and attrs.

Theming bottom app bars

Bottom app bars support Material Theming which can customize color, typography and shape.

Bottom app bar theming example

API and source code:

The following example shows a bottom app bar with Material Theming.

"Pink bottom app bar with pink diamond inset FAB and brown icons"

Implementing bottom app bar theming

Use theme attributes in res/values/styles.xml, which applies the theme to all bottom app bars and FABs and affects other components:

<style name="Theme.App" parent="Theme.Material3.*">
    ...
    <item name="colorPrimary">@color/shrine_pink_100</item>
    <item name="colorOnPrimary">@color/shrine_pink_900</item>
    <item name="colorSecondary">@color/shrine_pink_50</item>
    <item name="colorOnSecondary">@color/shrine_pink_900</item>
    <item name="textAppearanceTitleMedium">@style/TextAppearance.App.Medium</item>
    <item name="shapeAppearanceSmallComponent">@style/ShapeAppearance.App.SmallComponent</item>
</style>

<style name="TextAppearance.App.Medium" parent="TextAppearance.Material3.TitleMedium">
    <item name="fontFamily">@font/rubik</item>
    <item name="android:fontFamily">@font/rubik</item>
</style>

<style name="ShapeAppearance.App.SmallComponent" parent="ShapeAppearance.Material3.SmallComponent">
    <item name="cornerFamily">cut</item>
    <item name="cornerSize">4dp</item>
</style>

Use default style theme attributes, styles and theme overlays, which applies the theme to all bottom app bars and FABs but does not affect other components:

<style name="Theme.App" parent="Theme.Material3.*">
    ...
    <item name="bottomAppBarStyle">@style/Widget.App.BottomAppBar</item>
    <item name="floatingActionButtonStyle">@style/Widget.App.FloatingActionButton</item>
</style>

<style name="Widget.App.BottomAppBar" parent="Widget.Material3.BottomAppBar">
    <item name="materialThemeOverlay">@style/ThemeOverlay.App.BottomAppBar</item>
</style>

<style name="Widget.App.FloatingActionButton" parent="Widget.Material3.FloatingActionButton">
    <item name="materialThemeOverlay">@style/ThemeOverlay.App.FloatingActionButton</item>
</style>

<style name="ThemeOverlay.App.BottomAppBar" parent="">
    <item name="colorPrimary">@color/shrine_pink_100</item>
    <item name="colorOnPrimary">@color/shrine_pink_900</item>
    <item name="textAppearanceTitleMedium">@style/TextAppearance.App.TitleMedium</item>
</style>

<style name="ThemeOverlay.App.FloatingActionButton" parent="">
    <item name="colorSecondary">@color/shrine_pink_50</item>
    <item name="colorOnSecondary">@color/shrine_pink_900</item>
    <item name="shapeAppearanceSmallComponent">@style/ShapeAppearance.App.SmallComponent</item>
</style>

Use the styles in the layout, which affects only this bottom app bar and FAB:

<com.google.android.material.bottomappbar.BottomAppBar
    ...
    style="@style/Widget.App.BottomAppBar"
    />

<com.google.android.material.floatingactionbutton.FloatingActionButton
    ...
    style="@style/Widget.App.FloatingActionButton"
    />

In code:

val topEdge = BottomAppBarCutCornersTopEdge(
    bottomAppBar.fabCradleMargin,
    bottomAppBar.fabCradleRoundedCornerRadius,
    bottomAppBar.cradleVerticalOffset
)
val background = bottomAppBar.background as MaterialShapeDrawable
background.shapeAppearanceModel = background.shapeAppearanceModel.toBuilder().setTopEdge(topEdge).build()

Note: Using BottomAppBarCutCornersTopEdge is not necessary with rounded shapeAppearance corners.