List with labeled Scrollbars

Question

I'm trying to find out, how to implement a List with a labeled Scrollbar (like in Contacts-App). There is an alphabetically ordered List, and the first letter from the Contacts in the list is always on top. If I put my thumb on that scrollbar it shows me the current first letter from the items inside the list and lets me quickly navigate down/up while showing the first letter.

There must be an API for this, but I can't find it. It seems that "labeled Scrollbar" isn't the correct term for it. It would help a lot if someone can point me into the right direction.

I added a picture for better understanding:

How to achieve the J that appears on the scrollbar, and from where are the labels A..Z inside the List?

Answer 1

I finally found it out. The term I was searching for is "fast scrollbar". You can invoke it by setting setFastScrollEnabled(true) on a List View and provide an Adapter which implements a SectionIndexer