You dont patent an "idea." You patent a "method" or "process." For example, google couldn't patent Android, but the were able to patent the method of implementing their face unlock technology. Furthermore, I hope you realize that patenting is not expensive. Even the simplest software patent can hold a price tag with 4-5 digits.
My blog, Inverted Keystrokes
, is looking for aspiring developers (not necessarily with Android) to post articles. If you have any development experience and are interested in participating, please PM me. =)