I know it's not that hard. However, although I have experience in basic, I have no experience in play store. I need purchasing subroutines to use in my android software I developed in B4A. Subscriptions (weekly, montly, yearly and if exists daily), lifetime purchase and donation (an adjustable amount) procedures. These procedures to be in the form of a separate class and be called asynchronously from where it is needed. I want the SDK IDs to be stored in a string so they can be changed. Subroutines must be tried, that is, they must come from your already existing android software. Because I don't have time for trial and error. And of course it should be compatible with B4X's, Google Play Billing 5.0 library. More or less like @hatzisn 's (here). However it looks a bit old. I don't know if it is compatible with the Google's new version. Anyone want to arrange and give these routines for a fee? Thanks.
Dear Erel, thank you for your reply. actually i understood these procedures a little bit. but I chose such a method because I don't want any errors. One thing I've learned in my programming life, which I mostly pursue as a hobby, is that you can never do it alone. Help is needed for progress. If I can keep things going as I thought, I think you'll see me here a few more times. Thank you for giving advice.?