How to put a vector in a shape in Android

Question

I'm trying to make customizable icons in Android. I made the vector element, but now I want to give it a rounded background, so I tried to place it within a rounded shape. Like this:

<?xml version="1.0" encoding="utf-8"?>
<!-- drawable/circle_card_icon.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <vector xmlns:android="http://schemas.android.com/apk/res/android"
        android:height="24dp"
        android:width="24dp"
        android:viewportWidth="24"
        android:viewportHeight="24">
        <path android:fillColor="#000"
            android:pathData="M20,2H4A2,2 0 0,0 2,4V22L6,18H20A2,2 0 0,0 22,16V4A2,2 0 0,0 20,2M6,9H18V11H6M14,14H6V12H14M18,8H6V6H18" />
    </vector>
</shape>

Yet this doesn't work, and I'm trying to achieve the following:

By using only the vector I don't get the background.
(I used this website to generate the vector)