selector.xml

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

You must change the selector from state_enabled to state_checked ( in your menu xml, all the items are enables, so it will show the same color for all the items in bottomNavigationView)

Where do you need to create this selector.xml? Under menu folder?

@EzekielHawk
You need to add this selector to /res/drawable

You must change the selector from state_enabled to state_checked ( in your menu xml, all the items are enables, so it will show the same color for all the items in bottomNavigationView)

Yes to this!