item selected color in android BottomNavigationView

create a color directory in res folder and create your xml file for customize your bottom navigation items:

res/color/bottom_nav_color.xml:

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

and in your BottomNavigationView set app:itemTextColor and app:itemIconTint values to @color/bottom_nav_color

<android.support.design.widget.BottomNavigationView
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:id="@+id/main_navigation"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:layout_alignParentBottom="true"
   android:background="@color/actionBarColor"
   app:menu="@menu/my_navigation_items"
   app:itemTextColor="@color/bottom_nav_color"
   app:itemIconTint="@color/bottom_nav_color"/>

1. Make a xml file in the drawable folder with the name of navigation_view_colored.xml and put this inside:

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

2. Add the xml you created to app:itemIconTint

<com.google.android.material.bottomnavigation.BottomNavigationView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/bottom_navigation"
    android:layout_alignParentBottom="true"
    app:itemIconTint="@drawable/navigation_view_colored"
    app:itemTextColor="@color/blue"
    app:menu="@menu/bottom_navigation"
    android:background="?android:attr/windowBackground"/>

here is simple solution to your question

<android.support.design.widget.TabLayout
....
app:tabBackground="@drawable/tab_color_selector"
...
/>

the selector res/drawable/tab_color_selector.xml:

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

update tab item selector color what your required to.