How to make recyclerview clip through it's containter Relativelayouts's background

Question

I have created a cardview inside a recyclerview that is using a Relativelayout as a containter.

This is the xml code for the mainactivity

<androidx.constraintlayout.widget.ConstraintLayout 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:background="@drawable/gradient_background"
tools:context=".MainActivity">
<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/activity_rounded_bg"
    android:layout_marginTop="50dp">

    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:layout_editor_absoluteX="0dp"
        tools:layout_editor_absoluteY="67dp"
        android:paddingTop="10dp"
        android:paddingHorizontal="0dp"
        android:clipToPadding="true"
        tools:listitem="@layout/cardview_contact_item">

    </androidx.recyclerview.widget.RecyclerView>

</RelativeLayout>
<ImageButton
    android:id="@+id/btnAddContact"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#00FFFFFF"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.498"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="1.0"
    app:srcCompat="@drawable/ic_add_icon" />
    </androidx.constraintlayout.widget.ConstraintLayout>

I wanted to ask how can I use the Relativelayouts rounded rectangle background as a clipping mask for the recycler view, so that it cuts off on the either side