What Is The Response For Restore_transactions In Case Of Subscription Bought Twice?

I can't test this myself, because there is no way to completely terminate subscription, apparently. So, I want to test the following use case: user buys subscription, cancel's it (

Solution 1:

Note: You should use the RESTORE_TRANSACTIONS request type only when your application is installed for the first time on a device or when your application has been removed from a device and reinstalled.

Using RESTORE_TRANSACTIONS on a regular basis is not recommended because of performance impacts.

Taken right from Android Developers http://developer.android.com/guide/google/play/billing/billing_overview.html

Although I do understand your concern for the Subscription Billing. Google is pretty good about their API and how you should interact with purchases.

When you send a RESTORE_TRANSACTIONS request you will get two broadcast back. A RESPONSE_CODE and a PURCHASE_STATE_CHANGED. Here's the table from Google stating the different values you could receive.

Coming back to your question about buying two subscriptions: you should check to see if the user has bought a subscription with the GET_PURCHASE_INFORMATION request, if the Subscription is in the list check the Purchase State of the Subscription to see if you should continue with the purchase.

As for what you would get if you "Could" buy two of the same subscriptions, its (I want to say impossible) unlikely... But you will get two order transactions.

As long as you're always aware of the user transactions on your part, Google's API will do the rest. Good luck!