Support landscape for only one view in UINavigationController

Question

I have a navigation controller which have a few view controllers. I need to support all orientations for all view controllers except one special view controller which only supports landscape. This special view controller appears in the middle of the navigation stack. I have done quite a lot of research but couldn't find any good solution. Here are the links that I have read and tried.

http://www.iphonedevsdk.com/forum/iphone-sdk-development/3219-force-landscape-mode-one-view.html#post60435

How to rotate screen to landscape?

How to autorotate from portrait to landscape mode? iPhone - allow landscape orientation on just one viewcontroller http://goodliffe.blogspot.com/2009/12/iphone-forcing-uiview-to-reorientate.html

Next I am going to try to replace navigation controller with presentModalViewController in order to display the special view controller. Then I am going to create a new navigation view controller inside the special view controller to push the subsequent view controllers.

If anyone has a better idea, please let me know. Really appreciated!

UPDATE: I have successfully use the method I described above: replace pushViewController with presentModalViewController and create a new navigation controller.

Answer 1

Every view controller pushed onto the navigation controllers stack have to support the same orientations. This means that it is not possible to have some view controllers only supporting portrait and others only supporting landscape. In other words all view controllers on the same navigation controller stack should return the same in the delegate:

(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

But there is a simple solution to this! Here is an example for going from portrait to landscape. Here is the steps to do it and below is code to support it.

1. Create a ‘fake’ view controller that will be root in a sub navigation controller. This view controller should support landscape.
2. Create a new instance of a UINavigationController, add an instance of the ‘fake’ view controller as root and an instance of your landscape view controller as second view controller
3. Present the UINavigationController instance as modal from the parent view controller

First, create a new view controller (FakeRootViewController) with this code:

@interface FakeRootViewController : UIViewController
@property (strong, nonatomic) UINavigationController* parentNavigationController;
@end

@implementation FaceRootViewController
@synthesize parentNavigationController;
// viewWillAppear is called when we touch the back button on the navigation bar
(void)viewWillAppear:(BOOL)animated {
  // Remove our self from modal view though the parent view controller
  [parentNavigationController dismissModalViewControllerAnimated:YES];
}
(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
   return (interfaceOrientation == UIInterfaceOrientationIsLandscape(interfaceOrientation));
} 

Here is the code to present the view controller that you wish to show in landscape mode:

FakeRootViewController* fakeRootViewController = [[FakeRootViewController alloc] init];[fakeRootViewController.navigationItem setBackBarButtonItem:backButton]; // Set back button
// The parent navigation controller is the one containing the view controllers in portrait mode.
fakeRootViewController.parentNavigationController = parentNavigationController;

UINavigationController* subNavigationController = // Initialize this the same way you have initialized your parent navigation controller.

UIViewController* landscapeViewController = // Initialize the landscape view controller

[subNavigationController setViewControllers:
   [NSArray arrayWithObjects:fakeRootViewController, 
                                               landscapeViewController, nil] animated:NO];

[_navigationController presentModalViewController:subNavigationController animated:YES];

Remember that the landscapeViewController should also have this implementation:

(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
   return (interfaceOrientation == UIInterfaceOrientationIsLandscape(interfaceOrientation));
} 

Answer 2

There's a private API to force an orientation change. Put in your pushed view controller's -viewWillAppear::

if ([UIDevice instancesRespondToSelector:@selector(setOrientation:)]) {
    [[UIDevice currentDevice] setOrientation:UIInterfaceOrientationPortrait];
}

To suppress the compiler warning, add this to the .m file of your view controller:

@interface UIDevice()
- (void)setOrientation:(UIDeviceOrientation)orientation; // private API to let POIEntryVC be pushed over landscape route view
@end

As always, there's a risk of being rejected and a risk of breaking in future OS versions when using private APIs. Do at your own risk!

Generally, presenting a modal view controller is the better solution in most cases.