Customization of BottomNavigationView

Note : I am assuming that you know about how to use BottomNavigationView.

This example I will explain how to add selector for BottomNavigationView. So you can state on UI for icons and texts.

Create drawable bottom_navigation_view_selector.xml as

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item  android:color="@color/bottom_nv_menu_selected" android:state_checked="true" />
    <item android:color="@color/bottom_nv_menu_default" />
</selector>

And use below attributes into BottomNavigationView in layout file

app:itemIconTint="@drawable/bottom_navigation_view_selector" 
app:itemTextColor="@drawable/bottom_navigation_view_selector"

In above example, I have used same selector bottom_navigation_view_selector for app:itemIconTint and app:itemTextColor both to keep text and icon colors same. But if your design has different color for text and icon, you can define 2 different selectors and use them.

Output will be similar to below