Any iPhone SDK API available to promote 3G/GPRS over WiFi in an iPhone application

Question

Hi Guys,

I have a requirement to promote 3G/GPRS over WiFi connectivity in the iPhone application I am developing. Please let me know if this is possible and if yes, how?

The problem is when I have a WiFi network which is available and connected but not logged in using Captive Portal, I cannot use that WiFi network to perform the tasks which require internet connection. What i have noticed is Reachability API detects the available WiFi but I cannot use it as I am not logged in and so I am not connected to internet using this WiFi hotspot until I login. So I want to use 3G/GPRS to perform the tasks requiring internet connectivity.

iPhone's default behavior is it uses WiFi when its available and if not then only 3G/GPRS.

So please let me know if both 3G/GPRS and WiFi are available but I am connected to internet not using WiFi but 3G/GPRS how to use 3G/GRPS to perform the tasks requiring internet connectivity.

Regards,

Answer 1

Third-party applications don't get control of where their data comes from. About all you're going to be able to do is ask your users to turn wifi off while your application does its thing. If you need to get back onto wifi after doing the initial data transfer, you could make some clever use of the iOS 4 multitasking and local-notification APIs: when your application enters the background, it could start a background-task handler (using -beginBackgroundTaskWithExpirationHandler: in your app delegate's -applicationDidEnterBackground:) to wait for the wifi connection to become unavailable, do its thing with the cell network, then create a UILocalNotification to tell the user it's okay to turn wifi back on again. That way, the user could get the benefits of whatever your app does and still keep the connection they started out on.

Answer 2

If you are creating an app which needs to access certain network resource(s) to function, then you should just ping, or try to connect to those resources directly instead of just depending on reachability for the decision. If you can't ping your server, then have the app do the same thing it would if reachability reported zero connectivity (even though it may not be).