<Spinner
      android:id="@+id/spinner"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:entries="@array/array_name"
      app:validateSelected="@{spinnerLabel}"
      app:validateSelectedMessage="@{@string/spinnerErrorMessage}"
      app:validateSpinnerAutoDismiss="@{true}" />

<!-- Error label below -->
<TextView
      android:id="@+id/spinnerLabel"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />