Restrict iPhone app to Wifi

Question

Is it possible to restrict an iPhone app to only work if there's a Wifi connection (not 3G)?

Answer 1

Yes. There are two steps:

First, you need to add the UIRequiresPersistentWiFi key to your applications Info.plist. This ensures that the WiFi connection does not go to sleep while your application is open.

Secondly, you need to query the system (using the SCNetworkReachability API) to see which radio is currently enabled. See this question in the iPhone documentation.