I integrated barcode scanning for the Youth Impact Mobile app, that the staff will have to carry on them.
Below are some screenshots and a couple great starting reference pages. In total, it really took me no time to integrate barcode scanning via Intent. I'd say 30 minutes.
This is ZXing's page for their Intent Integrator:
What they left out on the page (and I requested them to add to their page), was a link to this class:
Obviously, the first image is taken from my tablet.. the application itself is pretty plain right now, Haven't added in any of the fragments to modify the participants information, but I have a couple fragments for that in my other project that I'll migrate over.