Selling apps on google play or paying directly in the app, how to implement it?

Question

Android

Write separate code or are there source codes and ready-made solutions?

Answer 1

Today I started working with this thing for the first time)
I read the official man, as well as an article on habré ( habrahabr.ru/post/203368 ) and for now I'm implementing using Helpers (/util)
https://github.com/Suvitruf/ android-sdk-examples - here is a good example