Perhaps the new Backup Agent (in 2.2: http://developer.android.com/reference/android/app/backup/BackupAgent.html ) can help with this, as that seems to allow an app to store backed up data between installs. That being said, I doubt this can be a guaranteed way to solve your problem, since the data it backs up is probably able to be deleted as well.
In my opinion, you should simply require the user obtain trial key from a server that records some device specific info and only gives out the trial based on your criteria. Storing anything on the phone anywhere at all is subject to user deletion. If you plan it well, your trial key will be a token with an expiration, and your app will know how to decode the token and verify that it has not expired. This method would require a network connection only once, and could even allow for the user to obtain the key using a computer if the device hasn't got any internet connection. (That would not be convenient for the user, of course!) -- 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
