maria3 - I won't be able to offer you a forum, but the developers will be happy https://www.dataxdev.com/services/android/ , I've also thought I’ll write everything myself, but without their help and refinement, it didn’t work at all. I didn't even know some of the important things that they told me to write my application. Yes, of course, I paid the money, but I don’t regret it a bit, because my application is in demand.