Why won't my UIViewController rotate with the device?

Q:  Why won't my UIViewController rotate with the device?

A: Why won't my UIViewController rotate with the device?

There can be several possible reasons your view controller does not rotate.

The UIViewController class provides the fundamental view-management model for iPhone applications. It provides automatic support for rotating the views of the view controller in response to changes to the orientation of the device. If the autoresizing properties of your view and subviews are properly configured, this behavior is essentially free. Your view controller may not rotate in certain situations if:

• The view controller does not implement this delegate method:

  - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation;

  Even if shouldAutorotateToInterfaceOrientation is implemented, you should make sure it returns YES for all the orientations you wish to support. To support all orientations, simply always return YES.

• The view controller's UIView property is embedded inside UIWindow but alongside an additional view controller.

  You may find a situation where shouldAutorotateToInterfaceOrientation is called once at startup for a given view controller but is never called again when the device is rotated. Because view controllers are tightly bound to the views they manage, they are also part of the responder chain used to handle events. View controllers are themselves descendants of the UIResponder class and are inserted into the responder chain between the managed view and its superview. So it is common practice to have one primary view controller in your application as part of the responder chain. You would typically add one primary view controller such as aUINavigationController, UITabBarController or a generic UIViewController to your UIWindow. For example, this is done by calling:

  [myWindow addSubview:primaryViewController.view];

  If you add an additional view controller's UIView property to UIWindow (at the same level as your primary view controller) via the following:

  [myWindow addSubview:anotherController.view];

  this additional view controller will not receive rotation events and will never rotate. Only the first view controller added to UIWindow will rotate.

  Note: You may add one view controller's UIView property as a subview to another view controller. In doing so, both views will rotate but the parent view controller remains in charge of determining the supported orientations via its shouldAutorotateToInterfaceOrientation method.

  Note: Keep in mind that UINavigationController and UITabBarController have the capability to manage a "stack" or "list" of view controllers on their own.

• You have added your view controller's UIView property to UIWindow as a subview, but prematurely released it soon after.

  UIWindow will retain that view, but not the view controller itself. You must not release it prematurely. Declare it as a "retainable" property in yourUIApplicationDelegate subclass.

  Note: UINavigationController and UITabBarController retain your view controllers, so you can release them once they have been added.

• All child view controllers in your UITabBarController or UINavigationController do not agree on a common orientation set.

  To make sure that all your child view controllers rotate correctly, you must implement shouldAutorotateToInterfaceOrientation for each view controller representing each tab or navigation level. Each must agree on the same orientation for that rotate to occur. That is, they all should return YES for the same orientation positions.

• Overriding the -(id)init: or -(id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle method without calling super. For the object to be initialized properly, you must call super on any init or initWithNibName method you are overriding for your view controllers.