Storyboards, Segues and Different views for different orientations - ios5

Question

I have been working on iOS5 and have been struggling with storyboards, segues and adjusting the views for different orientations. After going through some Apple's help for the past couple of days; I have not found one place for my answers, I have come to the following conclusions that I will articulate very carefully and I hope someone can tell me if I am correct:
1- Using a storyboard does not mean you have to use segues (yes this is confusion for a beginner).
2- You can only use segues between VCs that belong to a Navigation controller.
3- On the other hand, having a Navigation controller does not necessarily imply that you have to use a segue from one VC to another VC (yep!). So if you are trying to go from one VC to another VC (regardless of whether the first VC belongs to a Nav Controller or not),you can do the following:
Assume you have a WhiteVC class and a YellowVC class and you placed a button on the WhiteVC view (in the storyboard and changed the class of the generic VC to WhiteVC) and linked it to an IBAction in the WhiteVC class. This would be the code you would implement, in WhiteVC.m, to be able to click that button and have the YellowVC view appear:
-(IBAction)GoToYellow
{
YellowViewController *YellowVC=[self.storyboard instantiateViewControllerWithIdentifier:#"myYellowVC"];
[self presentViewController:YellowVC animated:YES completion:nil];
}
To return from the YellowVC to the WhiteVC, you would then create another button on the YellowVC view (follow same process as above) and use the following code:
-(IBAction)ReturnToWhiteVC
{
[self dismissViewControllerAnimated:YES completion:nil];
}
This will dismiss the YellowVC and return to the White VC.
4- It is not recommended to have one VC own (instantiate) multiple views - for different orientations for example- it is better to have a separate VC for each view. It is ok though to have VCs instantiate other VCs as part of the MVC.
5- Now all of this came about because I was building an app that has a Nav Controller but its root VC will be different (different VCs with different Views) depending on whether it is landscape or portrait. So I could either instantiate the VCs programmatically (like #3 above) which worked well. Or, if I wanted to do the transition using segues, the apple help docs provides the following code:
BOOL isShowingLandscapeView;
- (void)awakeFromNib
{
isShowingLandscapeView = NO;
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(orientationChanged:)
name:UIDeviceOrientationDidChangeNotification
object:nil];
}
- (void)orientationChanged:(NSNotification *)notification
{
UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
if (UIDeviceOrientationIsLandscape(deviceOrientation) && !isShowingLandscapeView)
{
[self performSegueWithIdentifier:#"AlternateView" sender:self];
isShowingLandscapeView = YES;
}
else if (UIDeviceOrientationIsPortrait(deviceOrientation) && isShowingLandscapeView)
{
[self dismissViewControllerAnimated:YES completion:nil];// breakpoint shows that this is triggered
isShowingLandscapeView = NO;
}
}
The above code obviously only applies with a Nav Controller (because of the segues) and it worked when the orientation changed from portrait to Landscape but when I rotate back to portrait, I end up with the landscape VC rotated back to portrait. What am I doing here wrong?
I hope someone can validate/confirm these points and answer my question.
Thanks
KB.

Answer 1

First of all : segues don't apply only with a UINavigationController, any UIViewController is able to perform a segue.
The Apple documentation also say that you'll have to restrict supported orientation of each UIViewController you'll use to handle orientation i.e. you'll have to restrict portrait to portrait only and landscape to landscape only). This could be done following the doc :
For iOS 6 and later : override supportedInterfaceOrientation
For iOS 5 and earlier : override shouldAutoRotateToInterfaceOrientation
Then, in order to use Apple design to manage orientation, you can follow this blog post by Alex Moffat.
It basically describe how to design your view hierarchy using two view controllers displaying the same content (one for Landscape and one for Portrait), embedded in a Navigations Controller. Both view controller should be able to push a hird view controller able to autorotate.
The main idea is to push/pop the Landscape view on/from the navigation stack, and to handle the transition with the third view accordingly.
You should be able to adapt it's code to your own view hierarchy.