How to make custom Scroll Bar image and A-Z effect in contacts?

I am creating a contacts like application with a listview. I would like to use the scrolling effect in android contacts which displays A-Z in the middle of the screen while we scroll on the contacts list.开发者_Python百科Also i want to implement custom scroll bar image?

Can anybody help me?

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check this API Demo >> Lists >> Array(Overlay )demo code.. it will help you..