Hi,
How to store information in iPhone so that it cannot be removed when application removed. For example to indicate if user already used all trial features. I tried to use [NSUserDefaults standardUserDefaults] - but it refreshed each time app deleted.
Thanks in advance
Apple doesn't allow you to do this. If Apps could leave files after they are uninstalled then you could have your disk fill up with no way to actually get rid of the stuff.
Some applications handle this by retrieving the device's unique identifier (UDID) and storing it one their servers. If the server sees the same UDID twice from the application's validation step, deny validation.
I think it’s possible to store such data in the keychain, see this forum. I also think it’s evil to do such a thing, as you are fighting the user, but it’s your choice.