How to set elevation to RecyclerView?

fragment_list.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:clipToPadding="false"
    android:gravity="center"
    android:padding="32dp">

    <TextView
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:text="TITLE............!"
        android:textAppearance="@style/TextAppearance.AppCompat.Headline" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/list"
        android:name="com.example.elevation.ItemFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/button"
        android:layout_below="@+id/title"
        android:background="@android:color/holo_blue_light"
        android:elevation="2dp"
        app:layoutManager="LinearLayoutManager"
        tools:context="com.example.elevation.ItemFragment"
        tools:listitem="@layout/fragment_item" />

    <Button
        android:id="@+id/button"
        style="@style/Base.Widget.AppCompat.Button.Colored"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:text="Button" />

</RelativeLayout>

android - How to properly set elevation value to recyclerview? - Stack Overflow
material design - Android "elevation" not showing a shadow - Stack Overflow

Elevation & shadows - Material design - Material design guidelines