material-dialogs/library/src/main/res/layout/md_progress_dialog_indeterminate.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="start|center_vertical">

    <ProgressBar
        android:id="@android:id/progress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="@dimen/md_dialog_frame_margin"
        android:layout_marginStart="@dimen/md_dialog_frame_margin" />

    <TextView
        android:id="@android:id/message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif"
        android:textSize="16sp"
        tools:text="Message"
        tools:ignore="UnusedAttribute" />

</LinearLayout>