<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center_horizontal"
    android:paddingBottom="@dimen/margin_small"
    android:paddingTop="@dimen/margin_small">

    <ProgressBar
        android:id="@+id/progressbar"
        style="?android:attr/progressBarStyleInverse"
        android:layout_width="28dp"
        android:layout_height="28dp"
        android:layout_centerVertical="true" />

</RelativeLayout>