Return to Top button layout

fragment_with_return_to_top_button.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:animateLayoutChanges="true">

    <Button
        android:id="@+id/button_return_to_top"
        android:layout_width="wrap_content"
        android:layout_height="24dp"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="@dimen/your_margin_i_dont_know"
        android:background="@drawable/bg_return_to_top"
        android:drawablePadding="8dp"
        android:drawableStart="@drawable/ic_up_arrow"
        android:paddingEnd="16dp"
        android:paddingStart="16dp"
        android:text="@string/return_to_top"
        android:textAllCaps="false"
        android:textColor="@color/white"
        android:textSize="12sp"
        android:visibility="gone" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:listitem="@layout/item_row" />
</FrameLayout>