Smile [Q] Need help for creating NavBar Replacement

I wish to create a NavBar replacement sort of like a floater and need pointers on where to start......
Sort of like Pie Controls and a Toucher combined in some sort of idea I'm having.
I want to know where and how I can start.....
I think maybe I'll need xposed and standout libraries.
But just some pointers in general on where to start coding from and how to do it
coz I believe this project will need root capabilities and I have only developed a basic textbox and spinner database projects uptil now.