Unlike iOS, Android doesn't have an index UI associated with ListViews that would make it easy to search through large data sets. Instead, Android implements something it calls "FastScroll". As you scroll through a large list, a draggable image can pop-up allowing you to drag the list much faster, displaying index information as you scroll.
this is typically configured by setting the property `fastScrollEnabled` on the ListView to `true`
Additionally there are ways that you can override this feature to create your own UI.