Martin Douderoff has good apple apps, plus he created gaz regans, Beachbum Berrys, PDT, Dave Wondrich Punch, and more.
It seems it’s easier to write apple apps than Android, so there are more cocktail apps on apple.
http://mixologytech.com/index.html
Personally I use Evernote and have over 4363 recipes on it at last count. Solid ones. But those are for my personal use and research. I have all of Beachbum Berry’s tiki drinks with attribution to the original creators name, time, and place; and other places variations. Quite a few books: Mr. Boston’s two latest editions, the ones Jim Meehan and then Jonathan Pogash edited. PDT, Death & Co., Dead Rabbit, Smugglers Cove, Morgenthalers, Boudreau’s, and many more of the best modern books, plus several hundred that were given to me personally by bartenders from all over the world. I also have quite a lot from the 1800’s-1940’s from old classic books, and various researchers like Ted Haigh. In addition around 100+ I created that have been put on bar menus around the USA.