Question [Q] Have a custom listview with A-Z filters on the right

I couldn't post this question in the Android Development section so posting it here.

I am enclosing an image of my application to make it easy to ask my question.The app shows 400 entries. I want to implement a A-Z filter on the right side of the listview containing the entries like the Android Contacts application shows and i have highlighted what exact functionality i want to implement.

I have looked over stackoverflow which tend to describe using a AbsListView or SectionIndexer .... but i think it only sections it, doesn't make a a-z filter on the right