I can't find anywhere definitively, if you build an app against the iOS 4 SDK, to thus support multitasking, does that mean the app won't work in iOS 3? If not, how can you support iOS features like multitasking but still support iOS 3? I'm sorry if there are Apple docs on this, I'm happy to read them, I just can't find them. Thank you
A:
No it does not. iOS 3 just ignores the delegate methods that get called.
However, if you try and launch a background task, you'll have to check for the API first, otherwise yeah, you'll not run on 3.
jer
2010-09-16 04:03:38
Okay, thank you very much!!
Bob Bobbio
2010-09-16 04:05:44
Feel free to tick the checkmark next to this question if it helped you out.
jer
2010-09-16 04:13:46
A:
You can build against a 4.x Base SDK, and set the Deployment Target to 3.x.
But you have to make sure not use any of the new 4.x APIs without checking for their availability first (or you will start to run, then crash as soon as you call one of those APIs on a device running 3.x). And you will need to test thoroughly on an actual device running iPhone OS 3.x since there is no simulator support for this kind of OS portability testing.
In some cases, converting a 3.x app to also allow what is called "multitasking" under 4.x is as easy as rebuilding the app using a new 4.x Base SDK, but leaving the deployment target where it was at 3.x, and adding an applicationWillResignActive: delegate to handle both suspend and potential termination.
hotpaw2
2010-09-16 04:23:51