The Lua-based game engine LÖVE (
https://love2d.org/) has an Android implementation that permits developing and running games. Apparently some people are using it for non-game Android applications (much like
@Kartik Agaram does in a different context). I don't quite see yet which limitations this implies. A game engine should be plenty good enough for my UI needs, but I am not sure I'd get access to all the system functions I'd want (reading out sensors, for example).