pdf reader + piano keyboard

When I'm learning music I have a sheet of music on the piano stand and play the notes on the keyboard.
I want to do the same on a 10" tablet.
pdf of the music displayed at the top, and scrollable.
Piano keyboard to play the notes on.

Both apps exist separately for Android but unless I try to jump ahead and flash GoSkreen Cornerstone onto a tablet to get multiple windows I can't overlay one on the other.

Does this exist as a single app ?

Thanks