That sort of thing was pretty hard to find on Android at one point. So much so I started (but never quite finished) writing a program to do exactly this.
These days I genearlly use Caustic. To be honest Caustic is *massive* overkill as a metronome. It is actually a fully fledged sequencer complete with a huge range of synths.
However the demo (which has song save disabled) is free so its easy to kick the tires and see what you think. If you create a nrew track and add a "BeatBox" to a track and set up the piano roll to something simple (four hi-hits and bass-snare-base-snare), set it to "pattern mode" and press play you'll get a feel for what I mean.
The nice thing about using a fully fledged program for this is you can develop simple patterns into more complete ideas by sequencing different drum patterns and maybe adding a little bass.