If it's just to upload sketches and not edit or compile it, look for avr-dude on android. That's what the Anrduino uses at least on Linux and you can steal the avr-dude configurations from there. To compile you would need avr-gcc and avr-libc, to edit them any editor or the java environment.
If that's problematic, a solution would be to have the editor and the compiler web-based and you just download the .hex file, which in turn you transfer tot he hardware with avr-dude. That should be possible, but I have no idea whether anyone ever did work in that direction.
Korman