iOS - UISupportedInterfaceOrientations and shouldAutorotateToInterfaceOrientation - ios

Question

I am looking for some clarification on how to allow only certain orientations for your iOS app. I am aware of UISupportedInterfaceOrientations and shouldAutorotateToInterfaceOrientation but I am a little confused on their uses and exactly how they fit together.
I attempted to use UISupportedInterfaceOrientations to only allow landscape orientations, which appeared to have no affect until I researched in to it and read that it affects the initial orientation. Upon testing this, my app does appear to only open in landscape but quickly rotates if the screen is portrait.
I know you can use shouldAutorotateToInterfaceOrientation to limit the allowed orientations, for example:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft) ||
(interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}
However, while doing some reading online I read shouldAutorotateToInterfaceOrientation is deprecated as of iOS6.
Basically my questions are:
What is the correct approach for limiting screen orientations across
multiple versions of iOS?
Is the only use of UISupportedInterfaceOrientations to limit the
initial orientation?
Edit:
To expand on the accepted answer, shouldAutorotate works in iOS6. As a quick fix if you've already implemented your logic in shouldAutorotateToInterfaceOrientation and/or you want to support earlier versions of iOS, you can do the following:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft) ||
(interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}
- (BOOL)shouldAutorotate {
return [self shouldAutorotateToInterfaceOrientation:self.interfaceOrientation];
}

Answer 1

The method you need to use for rotation instead of shouldAutorotateToInterfaceOrientation is just shouldAutorotate
Handling rotation, according to the AppleDoc for ViewControllers:
In iOS 6, your app supports the interface orientations defined in your app’s Info.plist file. A view controller can override the supportedInterfaceOrientations method to limit the list of supported orientations. Generally, the system calls this method only on the root view controller of the window or a view controller presented to fill the entire screen; child view controllers use the portion of the window provided for them by their parent view controller and no longer participate in directly in decisions about what rotations are supported. The intersection of the app’s orientation mask and the view controller’s orientation mask is used to determine which orientations a view controller can be rotated into.
You can override the preferredInterfaceOrientationForPresentation for a view controller that is intended to be presented full screen in a specific orientation.
The method shouldAutorotateToInterfaceOrientation is deprecated, as are some methods for handling responses to device rotation.
For supporting methods of multiple versions of iOS, Here's something else that Apple has said:
For compatibility, view controllers that still implement the shouldAutorotateToInterfaceOrientation: method do not get the new autorotation behaviors. (In other words, they do not fall back to using the app, app delegate, or Info.plist file to determine the supported orientations.) Instead, the shouldAutorotateToInterfaceOrientation: method is used to synthesize the information that would be returned by the supportedInterfaceOrientations method.
Taken from release notes

Answer 2

To answer your second question:
Yes, the "UISupportedInterfaceOrientations" entry in the Info.plist is used only for initial startup of your app, making sure it doesn't start your app in an orientation it doesn't support, so that it's not required to perform a rotation right away.
Also, overriding "application:supportedInterfaceOrientationsForWindow" in your AppDelegate is pretty useful if your app never wants to use particular orientations (e.g. for a game that only does landscape).
Lastly, and this is a common error, on iPhone and iPod Touch devices, the device should never rotate to UIInterfaceOrientationPortraitUpsideDown! That's because these devices (contrary to an iPad) do not let the user lock a device in landscape mode with the Lock soft button - that button only locks into portrait. Therefore, if a user, laying on his side, wants to use an app in landscape mode, he cannot do this if your app goes into the upside down orientation. But if you disallow that rotation, then it works.