program for android market

Question

I am getting close to finishing a program for android. While I can design it to have a trial time frame and "lock" after, I am having trouble determining how I can effectively unlock it after. As I am totally new to this type of development, I was hoping for a little help in the best way to go about it.

Does the customer buy the product after the trial and contact me and I send them an unlock code? Is there a library in the Java API to connect to google marketplace and determine that the user bought the product, then it can be unlocked that way?

EDIT: This program is slated to only run on the Android Tablet at this time and as I understand it not all tablets have cellular service and therefore much more limited connectivity.

Trial time frame should be as easy as record time of first run then if program is run X days (or hours or whatever) later, lock it. This will only test on startup as I will need to allow the user to finish their current submission with the program before I lock them.

As for billing, the program itself will have a payment plan similar to MMO games. Buy now for $X then a subscription at $Y (currently planned for a yearly license), or possibly first billing includes first subscription. How does the Billing API handle that situation? I would need to bill them for the program, then bill for the license, then require them to renew the license in whatever time frame I determine to be best.

Answer 1

I can give you an answer for providing the "unlock code" but the trial time frame could be implemented in a number of ways.

You're probably going to want to look into the in-app billing API that Google provides. You can find out all about it here: In-app Billing Overview | Android Developers. It allows you to give the users the option to either buy an item once (e.g. special in game item, feature purchase) or multiple times (e.g. in game gold or recurring subscription).

You would have to handle any content delivery that the application would need on your own server but the Billing API can handle the purchase and could just basically send your application a message saying that the user shouldn't be in trial mode anymore.