material-components_material-components-android/docs/components/BottomNavigation.md

Bottom Navigation

Bottom navigation bars allow movement between primary destinations in an app.

Contents

• Using bottom navigation
• Bottom navigation bar
• Theming

Using bottom navigation

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

A typical layout will look similar to this:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
  ...
  <com.google.android.material.bottomnavigation.BottomNavigationView
      android:id="@+id/bottom_navigation"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:menu="@menu/bottom_navigation_menu" />

</LinearLayout>

In bottom_navigation_menu.xml inside a menu resource directory:

<menu xmlns:android="http://schemas.android.com/apk/res/android">
  <item
      android:id="@+id/page_1"
      android:enabled="true"
      android:icon="@drawable/icon_1"
      android:title="@string/text_label_1"/>
  <item
      android:id="@+id/page_2"
      android:enabled="true"
      android:icon="@drawable/icon_2"
      android:title="@string/text_label_2"/>
</menu>

Note: BottomNavigationView does not support more than 5 menu items.

In code:

BottomNavigationView.OnNavigationItemSelectedListener { item ->
    when(item.itemId) {
        R.id.item1 -> {
            // Respond to navigation item 1 click
            true
        }
        R.id.item2 -> {
            // Respond to navigation item 2 click
            true
        }
        else -> false
    }
}

There's also a method for detecting when navigation items have been reselected:

bottomNavigation.setOnNavigationItemReselectedListener { item ->
    when(item.itemId) {
        R.id.item1 -> {
            // Respond to navigation item 1 reselection
        }
        R.id.item2 -> {
            // Respond to navigation item 2 reselection
        }
    }
}

That results in:

Making bottom navigation accessible

You should set an android:title for each of your menu items so that screen readers like TalkBack can properly announce what each navigation item represents:

<menu xmlns:android="http://schemas.android.com/apk/res/android">
  <item
      ...
      android:title="@string/text_label"/>
  ...
</menu>

The labelVisibilityMode attribute can be used to adjust the behavior of the text labels for each navigation item. There are four visibility modes:

• LABEL_VISIBILITY_AUTO (default): The label behaves as “labeled” when there are 3 items or less, or “selected” when there are 4 items or more
• LABEL_VISIBILITY_SELECTED: The label is only shown on the selected navigation item
• LABEL_VISIBILITY_LABELED: The label is shown on all navigation items
• LABEL_VISIBILITY_UNLABELED: The label is hidden for all navigation items

Adding badges

Initialize and show a BadgeDrawable associated with menuItemId, subsequent calls to this method will reuse the existing BadgeDrawable:

var badge = bottomNavigation.getOrCreateBadge(menuItemId)
badge.isVisible = true
// An icon only badge will be displayed unless a number is set:
badge.number = 99

As best practice if you need to temporarily hide the badge (e.g. until the next notification is received), change the visibility of BadgeDrawable:

val badgeDrawable = bottomNavigation.getBadge(menuItemId)
    if (badgeDrawable != null) {
        badgeDrawable.isVisible = false
        badgeDrawable.clearNumber()
    }

To remove any BadgeDrawables that are no longer needed:

bottomNavigation.removeBadge(menuItemId)

See the BadgeDrawable documentation for more information about it.

Bottom navigation bar

Bottom navigation bar example

API and source code:

• BottomNavigationView
  • Class description
  • Class source

The following example shows a bottom navigation bar with four icons:

• favorites
• music note
• places
• news

In layout.xml:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

  <com.google.android.material.bottomnavigation.BottomNavigationView
      android:id="@+id/bottom_navigation"
      style="@style/Widget.MaterialComponents.BottomNavigationView.Colored"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:menu="@menu/bottom_navigation_menu" />

</LinearLayout>

In bottom_navigation_menu.xml inside a menu resource directory:

<menu xmlns:android="http://schemas.android.com/apk/res/android">
  <item
      android:id="@+id/page_1"
      android:enabled="true"
      android:icon="@drawable/ic_favorite"
      android:title="@string/favorites"/>
  <item
      android:id="@+id/page_2"
      android:enabled="true"
      android:icon="@drawable/ic_music"
      android:title="@string/music"/>
  <item
      android:id="@+id/page_3"
      android:enabled="true"
      android:icon="@drawable/ic_places"
      android:title="@string/places"/>
  <item
      android:id="@+id/page_4"
      android:enabled="true"
      android:icon="@drawable/ic_new"
      android:title="@string/news"/>
</menu>

In code:

bottomNavigation.selectedItemId = R.id.page_2

Anatomy and key properties

The following is an anatomy diagram for the bottom navigation bar:

• (1) Container
• Navigation items:
  • (2) Inactive icon
  • (3) Inactive text label
  • (4) Active icon
  • (5) Active text label

Container attributes

	Attribute	Related methods	Default value
Color	app:backgroundTint	N/A	?attr/colorSurface
Elevation	app:elevation	setElevation	8dp

Navigation item attributes

	Attribute	Related methods	Default value
Menu resource	app:menu	inflateMenu getMenu	N/A
Ripple (inactive)	app:itemRippleColor	setItemRippleColor getItemRippleColor	?attr/colorOnSurface at 8% (see all states)
Ripple (active)	"	"	?attr/colorPrimary at 8% (see all states)
Label visibility mode	app:labelVisibilityMode	setLabelVisibilityMode getLabelVisibilityMode	LABEL_VISIBILITY_AUTO

Icon attributes

	Attribute	Related methods	Default value
Icon	android:icon in the menu resource	N/A	N/A
Size	app:itemIconSize	setItemIconSize setItemIconSizeRes getItemIconSize	24dp
Color (inactive)	app:itemIconTint	setItemIconTintList getItemIconTintList	?attr/colorOnSurface at 60%
Color (active)	"	"	?attr/colorPrimary

Text label attributes

	Attribute	Related methods	Default value
Text label	android:title in the menu resource	N/A	N/A
Color (inactive)	app:itemTextColor	setItemTextColor getItemTextColor	?attr/colorOnSurface at 60%
Color (active)	"	"	?attr/colorPrimary
Typography (inactive)	app:itemTextAppearanceInactive	setItemTextAppearanceInactive getItemTextAppearanceInactive	?attr/textAppearanceCaption
Typography (active)	app:itemTextAppearanceActive	setItemTextAppearanceActive getItemTextAppearanceActive	?attr/textAppearanceCaption

Styles

	Style	Container color	Icon/Text label color (inactive)	Icon/Text label color (active)
Default style	Widget.MaterialComponents.BottomNavigationView	?attr/colorSurface	?attr/colorOnSurface at 60%	?attr/colorPrimary
Colored style	Widget.MaterialComponents.BottomNavigationView.Colored	?attr/colorPrimary	?attr/colorOnPrimary at 60%	?attr/colorOnPrimary
Dark theme supported style	Widget.MaterialComponents.BottomNavigationView.PrimarySurface	?attr/colorPrimary in light theme ?attr/colorSurface in dark theme	?attr/colorOnPrimary at 60% in light theme ?attr/colorOnSurface at 60% in light theme	?attr/colorOnPrimary in light theme ?attr/colorPrimary in dark theme

Default style theme attribute: ?attr/bottomNavigationStyle

Note: The Widget.MaterialComponents.BottomNavigationView.PrimarySurface style will automatically switch between between the component's primary colored style in light theme and surface colored style in dark theme. More information in the Dark theme documentation.

See the full list of styles and attributes.

Theming a bottom navigation bar

Bottom navigation supports Material Theming and can be customized in terms of color and typography.

Bottom navigation theming example

API and source code:

• BottomNavigationView
  • Class description
  • Class source

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

Implementing bottom navigation theming

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

<style name="Theme.App" parent="Theme.MaterialComponents.*">
    ...
    <item name="bottomNavigationStyle">@style/Widget.MaterialComponents.BottomNavigationView.Colored</item>
    <item name="colorPrimary">@color/shrine_pink_100</item>
    <item name="colorOnPrimary">@color/shrine_pink_900</item>
</style>

Or using a default style theme attribute, styles, and a theme overlay (themes all bottom navigation bars but does not affect other components):

<style name="Theme.App" parent="Theme.MaterialComponents.*">
    ...
    <item name="bottomNavigationStyle">@style/Widget.App.BottomNavigationView</item>
</style>

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

<style name="ThemeOverlay.App.BottomNavigationView" parent="">
    <item name="colorPrimary">@color/shrine_pink_100</item>
    <item name="colorOnPrimary">@color/shrine_pink_900</item>
</style>

Or using the style in the layout (affects only this specific bottom navigation bar):

<com.google.android.material.bottomnavigation.BottomNavigationView
    ...
    style="@style/Widget.App.BottomNavigationView"
/>