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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

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 for informing the user as to what each action performs. While optional, their use is strongly encouraged.

Content descriptions

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

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, this can be achieved via the app:navigationContentDescription attribute or setNavigationContentDescription method.

For action items and items within the overflow menu, the content description needs to be set 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, an action icon, a cradled FAB, and an overflow menu.

Purple bottom app bar with white icons and teal 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.MaterialComponents.BottomAppBar.Colored"
        app:navigationIcon="@drawable/ic_menu_24dp"
        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/search"
        android:icon="@drawable/ic_search_24dp"
        android:title="@string/search"
        android:contentDescription="@string/content_description_search"
        app:showAsAction="ifRoom"
        />

    <item
        android:id="@+id/more"
        android:title="@string/more"
        android:contentDescription="@string/content_description_more"
        app:showAsAction="never"
        />

</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.search -> {
            // Handle search icon press
            true
        }
        R.id.more -> {
            // Handle more item (inside overflow menu) press
            true
        }
        else -> false
    }
}

Applying scrolling behavior to the bottom app bar

The following example shows the bottom app bar hiding upon scrolling the scrollable content down, and appearring upon 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. Navigation icon (optional)
  3. Floating action button (FAB) (optional)
  4. Action item(s) (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 8dp
Height android:minHeight setMinimumHeight
getMinimumHeight		 56dp (default) and 64dp (w600dp)

Navigation icon attributes

Element Attribute Related method(s) Default value
Icon app:navigationIcon setNavigationIcon
getNavigationIcon		 null
Color N/A N/A ?attr/colorControlNormal (as Drawable tint)

FAB attributes

Element Attribute Related method(s) Default value
Alignment mode app:fabAlignmentMode setFabAlignmentMode
getFabAlignmentMode		 center
Animation mode app:fabAnimationMode setFabAnimationMode
getFabAnimationMode		 scale
Cradle margin app:fabCradleMargin setFabCradleMargin
getFabCradleMargin		 5dp
Cradle rounded corner radius app:fabCradleRoundedCornerRadius setFabCradleRoundedCornerRadius
getFabCradleRoundedCornerRadius		 8dp
Cradle vertical offset app:fabCradleVerticalOffset setCradleVerticalOffset
getCradleVerticalOffset		 0dp

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)

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.MaterialComponents.*
Item typography textAppearanceSmallPopupMenu and textAppearanceLargePopupMenu in app:popupTheme or app theme N/A ?attr/textAppearanceSubtitle1

Styles

Element Style
Default style Widget.MaterialComponents.BottomAppBar
Primary background color style Widget.MaterialComponents.BottomAppBar.Colored
Primary (light theme) or surface (dark theme)
background color style		 Widget.MaterialComponents.BottomAppBar.PrimarySurface

Default style theme attribute: bottomAppBarStyle

See the full list of styles and attrs.

Theming bottom app bars

Bottom app bars support Material Theming and can be customized in terms of 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

Using theme attributes in res/values/styles.xml (themes all bottom app bars and FABs and affects other components):

<style name="Theme.App" parent="Theme.MaterialComponents.*">
    ...
    <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="textAppearanceSubtitle1">@style/TextAppearance.App.Subtitle1</item>
    <item name="shapeAppearanceSmallComponent">@style/ShapeAppearance.App.SmallComponent</item>
</style>

<style name="TextAppearance.App.Subtitle1" parent="TextAppearance.MaterialComponents.Subtitle1">
    <item name="fontFamily">@font/rubik</item>
    <item name="android:fontFamily">@font/rubik</item>
</style>

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

or using default style theme attributes, styles and theme overlays (themes all bottom app bars and FABs but does not affect other components):

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

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

<style name="Widget.App.FloatingActionButton" parent="Widget.MaterialComponents.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="textAppearanceSubtitle1">@style/TextAppearance.App.Subtitle1</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>

or using the styles in the layout (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.