When an user installs an Android App from Google Play, he/she has to login with a Google Account: does exists an Android API for getting which Google Account has been used for the App installation?
I would like to sell my App from Google Play, but I would give to the buyer a free trial period. I can't use subscriptions because they require a recurring payment (monthly or yearly), whereas I would set a una-tantum price.
When the trial period expire, I can use a non-consumable In-app product, but how can I manage the trial period?
Both Google Play Licensing and In-app Billing track purchase information on a per-user basis, thus they should be able to know which user has downloaded the App or who is the current user, and I too would like to know the same info in order to manage the trial period by means my web server.
If someone of you can suggest another way, I appreciate.