how would one start developing cross platform mobile apps with this? From what I have read, they only provide the GUI part? So the logic (GPS, Contacts etc) has to be handled by something else? Anyone knows?
For now, yes. But we are working on it. Recently, we released Pyjnius (http://github.com/kivy/pyjnius) to access dynamically Java from Python. That way, we can access to various Android API without any Java code. We are doing the same with objective-C: pyobjus (http://github.com/kivy/pyobjus), but not yet finished.
