Free & premium game with both same NSUserdefaults

Question

I Want to publish 2 versions of my game, 1 for free with advertisement and 1 premium.

But if the user is in level 9 in the free version and it buys the premium, than it should begin from level 9 in the premium version.

How do I do this?

Answer 1

You can take advantage of the ability to share NSUserDefaults suites between applications.

[[NSUserDefaults alloc] initWithSuiteName:@"yourGroupIdentifier"];

To enable your apps for this functionality you need to enable App Groups in your targets:

• Select the project file in the Xcode Project Navigator
• Select your target
• Select the tab Capabilities
• Enable App Groups and give it a name ("yourGroupIdentifier")

Initialising NSUserDefaults as shown above in both your apps will enable you to read and write the same defaults from both apps.

Having said that, I would suggest to use an In-App Purchase to unlock the pro version, instead of having 2 different products; for a better user experience.