add_product_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginBottom="@dimen/bottom_nav_height"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <!--Recycler view to show selected categories of user-->
    <android.support.v7.widget.RecyclerView
        android:orientation="vertical"
        android:id="@+id/category_recycler_view"
        android:layout_gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="10dp"/>

    <!--Floating button to add categories-->
    <android.support.design.widget.FloatingActionButton
        android:layout_marginRight="15dp"
        android:layout_marginEnd="15dp"
        android:layout_marginBottom="15dp"
        android:id="@+id/fab_button"
        android:clickable="true"
        android:layout_gravity="bottom|end"
        android:src="@drawable/ic_add_white_24dp"
        android:layout_width="56dp"
        android:layout_height="56dp"
        app:elevation="10dp" />

</FrameLayout>