Am I getting the steps right for verifying a user's Android in-app subscription?

Question

I am making an app that does not require a user account/login, and allows the user to purchase a subscription. I want to use the Google Play Developer API to verify whether

Answer 1

I may misunderstand your question, but I don't see a reason for you to be using the links you're referencing to get In-App Billing for an Android app working. This page is much more helpful:

http://developer.android.com/guide/google/play/billing/index.html

You can try out the demo application they include (Dungeons -- http://developer.android.com/guide/google/play/billing/billing_integrate.html#billing-download). That uses products (one-time purchases) rather than subscriptions, but you should be able to modify to test for what you want.

I think the key, for you, would be the restoreTransactions method they provide in the sample to see if the Google Play account has any subscriptions for your app:

@Override
public void onRestoreTransactionsResponse(RestoreTransactions request, int responseCode) {
    if (responseCode == BillingVars.OK) {                        
        // Update the shared preferences so that we don't perform a RestoreTransactions again.
        // This is also where you could save any existing subscriptions/purchases the user may have.
        SharedPreferences prefs = getSharedPreferences(my_prefs_file, Context.MODE_PRIVATE);
        SharedPreferences.Editor edit = prefs.edit();
        edit.putBoolean(DB_INITIALIZED, true);
        edit.commit();
    } else {
        Log.e(TAG, "RestoreTransactions error: " + responseCode);
    }
}