Display Badge on Top of Bottom Navigation Bar's Icon

Display badge on top of bottom navigation bar's icon

Adding badges is natively supported now, using the latest material dependency
add this to your build.gradle

    implementation 'com.google.android.material:material:1.1.0-alpha09'

in your layout add this

<!-- The rest of your layout here ....-->

  <com.google.android.material.bottomnavigation.BottomNavigationView
            android:id="@+id/bottom_navigation"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:menu="@menu/bottom_nav_menu"
            />

then you can just

     val navBar  = findViewById<BottomNavigationView>(R.id.bottom_navigation)
     navBar.getOrCreateBadge(R.id.action_add).number = 2

R.id.action_add for you would be the id of the menu item you want to put a badge on. Check it from the menu file you feed to the BottomNavigationView.

Make sure your app theme is in Theme.MaterialComponents

you can check it in styles or manifest.
for this example mine was this

     <style name="AppTheme" parent="Theme.MaterialComponents.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="android:statusBarColor" tools:targetApi="lollipop">@color/colorPrimary</item>
    </style>

How to display badge on items of bottomNavigationView android?

You should change your code to this

BottomNavigationMenuView menuView = (BottomNavigationMenuView) bottomNavigationView.getChildAt(0);
BottomNavigationItemView itemView = (BottomNavigationItemView) menuView.getChildAt(1);

Edit

To have more items having badge, you need to create another layout and so on

BottomNavigationMenuView menuView = (BottomNavigationMenuView) bottomNavigationView.getChildAt(0);
BottomNavigationItemView itemView = (BottomNavigationItemView) menuView.getChildAt(0);

notificationBadge = LayoutInflater.from(this).inflate(R.layout.notification_badge, menuView, false);
TextView textView = notificationBadge.findViewById(R.id.counter_badge);
textView.setText("15");
itemView.addView(notificationBadge);

BottomNavigationMenuView menuView1 = (BottomNavigationMenuView) bottomNavigationView.getChildAt(0);
BottomNavigationItemView itemView1 = (BottomNavigationItemView) menuView1.getChildAt(1);

notificationBadgeOne = LayoutInflater.from(this).inflate(R.layout.notification_badge_one, menuView1, false);
TextView textView = notificationBadgeOne.findViewById(R.id.counter_badge);
textView.setText("15");
itemView1.addView(notificationBadgeOne);

Android BottomNavigationView with Badge

---Note---

Badges will soon be supported out the box. However this might be useful if you really want to add custom views to your tabs.

Create Layout With BottomNavigationView

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <FrameLayout
        android:id="@+id/tabsRootFrameLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/tabsRootBottomNavigation" />
    <android.support.design.widget.BottomNavigationView
        android:id="@+id/tabsRootBottomNavigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="@android:color/white"
        local:menu="@menu/root_bottom_navigation_menu"
        local:itemIconTint="@color/bottom_navigation_selector"
        local:itemTextColor="@color/bottom_navigation_selector"
        local:elevation="16dp" />
</RelativeLayout>

Menu: root_bottom_navigation_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/tab_search"
        android:enabled="true"
        android:icon="@drawable/search_icon"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/tab_profile"
        android:enabled="true"
        android:icon="@drawable/profile_icon"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/tab_my_car"
        android:enabled="true"
        android:icon="@drawable/car_icon"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/tab_notifications"
        android:enabled="true"
        android:icon="@drawable/bell_icon"
        app:showAsAction="ifRoom" />
</menu>

Create Badge Layout: component_tabbar_badge.axml

<?xml version="1.0" encoding="UTF-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="@dimen/margin_tiny">
    <TextView
        android:id="@+id/notificationsBadgeTextView"
        android:layout_width="16dp"
        android:layout_height="16dp"
        android:layout_gravity="top|center_horizontal"
        android:layout_marginLeft="10dp"
        android:layout_marginStart="10dp"
        android:background="@drawable/notification_red_dot"
        android:gravity="center"
        android:textColor="@color/white"
        android:textSize="9dp" />
</FrameLayout>

Red Dot Background: notification_red_dot.xml

<?xml version="1.0" encoding="UTF-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid
        android:color="@color/red" />
    <size
        android:width="10dp"
        android:height="10dp" />
</shape>

Add Badge Layout To Bottom Navigation

private void SetNotificationBadge()
{
    _bottomNavigation = FindViewById<BottomNavigationView>(Resource.Id.tabsRootBottomNavigation);
    var notificationsTab = _bottomNavigation.FindViewById<BottomNavigationItemView>(Resource.Id.tab_notifications);
    View badge = LayoutInflater.From(this).Inflate(Resource.Layout.component_tabbar_badge, notificationsTab, false);
    _notificationBadgeTextView = badge.FindViewById<TextView>(Resource.Id.notificationsBadgeTextView);
    notificationsTab.AddView(badge);
}

Bind Badge Text

    var set = this.CreateBindingSet<TabsRootActivity, TabsRootViewModel>();
    set.Bind(_notificationBadgeTextView).To(vm => vm.UnreadNotificationsCount);
    set.Apply();

Result

Sample Image

Displaying notification badge on BottomNavigationBar's Icon

Yes. It can be done by stacking two icons using the Stack and Positioned widget.

      new BottomNavigationBarItem(
        title: new Text('Home'),
        icon: new Stack(
          children: <Widget>[
            new Icon(Icons.home),
            new Positioned(  // draw a red marble
              top: 0.0,
              right: 0.0,
              child: new Icon(Icons.brightness_1, size: 8.0, 
                color: Colors.redAccent),
            )
          ]
        ),
      )

How to add badge to BottomNavigationBarItem in Flutter?

Remove the const keyword before declaring the items inside BottomNavigationBar

How to display badge for a menuItem of BottomNavigationView of material library (version 1.1.0-alpha08)?

First migrate your project to androidX. How to migrate
Include dependency in your build.gradle:

implementation 'com.google.android.material:material:version' Get Version

Your Base AppLevel theme should use Material Component Theme like:

Your App Level Theme

  <style name="AppTheme" parent="Theme.MaterialComponents.Light.DarkActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

Activity code:

val menuItemId: Int = btm_nav.menu.getItem(0).itemId //0 menu item index.
badgeDrawable = btm_nav.getOrCreateBadge(menuItemId)
badgeDrawable.isVisible = true
badgeDrawable.number = 10

badgeDrawable.badgeGravity = BadgeDrawable.TOP_END    //badge gravity
//BadgeDrawable.TOP_START
//BadgeDrawable.BOTTOM_END
//BadgeDrawable.BOTTOM_START

badgeDrawable.isVisible = false   //hide badge
badgeDrawable.clearNumber()

XML layout:

 <com.google.android.material.bottomnavigation.BottomNavigationView
      android:id="@+id/btm_nav"
      style="@style/Widget.Design.BottomNavigationView"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:menu="@menu/bottom_nav_menu"/>

Display Badge on Top of Bottom Navigation Bar's Icon