View Stack, UIViewController, and Rotation - ios

Question

I have a UIViewcontroller that hosts a lot of Viewcontrollers. I set up autorotating on it and its subview and it works fine once the app has loaded. The problem I have is that during the initial loading process, the app has to connect and download some files locally. During this load if the user rotates the iPad the UIViewController doesn't rotate properly! I did set the flags and shouldautorotate but still not working.
PS : I am allowing these four orientations :
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait ||
interfaceOrientation == UIInterfaceOrientationLandscapeLeft ||
interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown ||
interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}
After the load is complete the behavior is correct and rotates properly. Now I thought this could be because some of those inner VC's are loading some data, let me explain:
The big View Controller hosts all other VC's ( Let's Call him BigDaddy), in the Viewdidload of bigdaddy I have (for argument sake ) three other ViewControllers : Busta, Skeezix, and lawrence. So I do:
[[Busta alloc] initWithNibName:#"Busta" bundle:nil];
and this in turn calls the -viewDidLoad of Busta, so I made the file loading section of that asynchronous by doing:
dispatch_async(dispatch_get_main_queue(), ^{
});
Those changes did help a little bit, in the sense that before the async dispatch the load process would take 5 seconds (and in those seconds any tilt in the iPad would cause the rotation event and my whole view is gone. Now I got those 5 seconds down to 1.2 seconds.
My question is, is there a solution to my problem? Will it never work? Is it possible to have an app rotate in four directions and respond to rotation changes while loading data?

Answer 1

I suspect the issue is with how you're doing your 'connect'. I assume you mean you're connecting to a remote server using NSURLConnection or similar. Be aware that if you use a synchronous connection on the main thread, you will freeze the app until the connection is finished. The appropriate method is to utilize the asynchronous calls, or better yet move the work to a secondary thread (see NSOperationQueue documentation) and then move any updating of the UI based on that information back to the main thread (see again the NSOperationQueue documentation).
There is a good example for this in the WWDC 2012 videos.

Answer 2

Why not just implement your -shouldAutorotateToInterfaceOrientation... method such that it allows rotation only after the app has finished loading the required data?
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
BOOL appIsFinishedLoadingData = <your code here>
return shouldRotate;
}
(I shortened your code in consideration of the fact that you're allowing all possible rotations, so there's really no need to check which rotation is being offered. Your way is more future-proof, mine is a little easier to read.)