How do you maintain 2 sets of in-app purchase code for Google Play and Amazon App Store

Question

From the past 1 year survey (Not sure it is still valid), it seems that developers generate more revenue in Amazon App Store than Google Play. That's surprising, as I thought Google Play is found in every Android devices. It suppose to generate most revenue. Not sure why.

Hence, I was planning to give a try in Amazon App Store. However, I realize I need to maintain 2 set of in-app purchase code, for Google Play and Amazon App Store?

I was wondering, how do most of you maintain such code? Besides using RoboBillingLibrary . I still try not to rely on 3rd party library, unless I really have to. As it is not easy to have a stable in-app purchase flow. I receive crash report once a while regarding in-app purchase, and have no idea why. Although almost all the code is just merely copy n paste from official code example.

Answer 1

I use a BAT file to build the different versions (Android, Kindle Fire, iOS). Each version is built with a different value for a conditional compilation symbol that indicates the target marketplace.

I use this approach for my code:

1. Create an interface IBilling, with typical members being init(), isAvailable(), purchase(sku), getInventory(player), etc.
2. Create classes Billing, BillingGoogle, BillingAmazon, and BillingApple. All implement IBilling.

3. In each method of the main Billing class, the conditional compilation symbol is used to call the corresponding method in one of the three market Billing classes. The market-specific code handles the details.

    class Billing implements IBilling { void init() { if marketplace-conditional-var == 'G' BillingGoogle.init(); if marketplace-conditional-var == 'A' BillingAmazon.init(); if marketplace-conditional-var == 'P' BillingApple.init(); } // similar code for isAvailable(), purchase(sku), etc. follows }