I was thinking of implementing a coupon based system for my app so I could offer some copies of the full version to some people. I found blog article which provided the server code (to install on Google AppEngine) and the client code to use on the app. I looked at the source code and realized the way the system works (after the coupon has been validated and activated) is with a simple a boolean variable with SharedPreferences.
*1) *My main question about this is, how safe is this? How easily is the SharedPreferences file hackable on rooted devices to change that boolean flag and "convert" an app to a full version even without a coupon code? I'm talking about coupons here but they don't really matter. I thought about using SharedPreferences before to handle a similar situation (ie: boolean variable to control if the app is the full version or not). So the question is really about SharedPreferences and how safe are they to control the free/paid version of an app based on a boolean flag. If they are not safe, is there any other way? *2)* My second question and now related to the coupons system but we can look at this as validating and activating an app through the Internet. The idea is that I just want to activate the full version of my app to someone, temporarily, some sort of a trial. The problem is the deactivating part. Let's say I disable the full version for a specific device on the validation server. If the user doesn't open my app while connected to the Internet, the app will always be on "full mode" and there's nothing I can do about it. Or is there? -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
