element-android/vector/src/main/res/layout/activity_simple.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/vector_coordinator_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/simpleFragmentContainer"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <RelativeLayout
        android:id="@+id/simpleActivityWaitingView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:background="?attr/colorBackgroundFloating"
        android:gravity="center"
        android:padding="8dp"
        android:visibility="gone"
        tools:visibility="visible">

        <ProgressBar
            android:id="@+id/waiting_view_status_circular_progress"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:layout_centerInParent="true"
            android:layout_gravity="center_vertical" />

    </RelativeLayout>

</androidx.coordinatorlayout.widget.CoordinatorLayout>