They're two completely separate things so it's impossible to compare them. I would say it is the same general idea though as to write a script you need to know minimal Java and more of the API. The same concept applies to building an app for android. You may have no idea what you're doing or why things work (android abstracts you away from most of the internal stuff) but you'll still be able to make something.
FYI you use XML quite a bit with app making, however it's incredibly simple and after a few tutorials you'll get the hang of how to use it.