https://github.com/kivy/kivy is going strong. I ported a web app to a native 2button + list android app in 245 lines of code with flask and requests.
You can also use jnius to autoclass in any android java library. Kivy is well worth a try. A lot has happened in the last year.
There is actually a fresh book released a few days ago I'm looking to buy:
https://www.amazon.com/Building-Android-Python-Using-Studio/dp/1484250303