This link is a good resource for how to style/theme the Android RatingBar component. The default RatingBar component uses “stars” that the user can tap, but for some (many?) user interfaces, you’ll probably want to use something besides the default stars.
This SO post mentions a couple of style attributes that can also be used when styling the RatingBar:
The source makes reference to style "?android:attr/ratingBarStyleIndicator" in addition to the "?android:attr/ratingBarStyleSmall" that you're already familiar with. ratingBarStyleIndicator is slightly smaller but it's still pretty ugly and the comments note that these styles "don't support interaction".