session-android/res/layout/registration_unlock_dialog_view.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="vertical"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_gravity="center_horizontal"
              android:animateLayoutChanges="true">

    <ProgressBar android:id="@+id/progress"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"
                 android:visibility="gone"
                 tools:visibility="visible"/>

</LinearLayout>