element-android/vector/src/main/res/layout/activity_progress.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:background="?vctr_waiting_background_color">

    <ProgressBar
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_gravity="center" />

</FrameLayout>