IOS 6 force device orientation to landscape

Ok, folks, I will post my solution.

What I have:

1. A view based application, with several view controllers. (It was navigation based, but I had to make it view based, due to orientation issues).
2. All view controllers are portrait, except one – landscapeLeft.

Tasks:

1. One of my view controllers must automatically rotate to landscape, no matter how the user holds the device. All other controllers must be portrait, and after leaving the landscape controller, the app must force rotate to portrait, no matter, again, how the user holds the device.
2. This must work as on IOS 6.x as on IOS 5.x

Go!

(Update Removed the macros suggested by @Ivan Vučica)

In all your PORTRAIT view controllers override autorotation methods like this:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation{
    return (toInterfaceOrientation == UIInterfaceOrientationPortrait);
}
-(BOOL)shouldAutorotate {
    return YES;
}
- (NSUInteger)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskPortrait;
}

You can see the 2 approaches: one for IOS 5 and another For IOS 6.

The same for your LANDSCAPE view controller, with some additions and changes:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation{
    [image_signature setImage:[self resizeImage:image_signature.image]];
    return (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft);
}
-(BOOL)shouldAutorotate {
    return YES;
}
- (NSUInteger)supportedInterfaceOrientations {
    [image_signature setImage:[self resizeImage:image_signature.image]];
    return UIInterfaceOrientationMaskLandscapeLeft;
}

ATTENTION: to force autorotation in IOS 5 you should add this:

- (void)viewDidLoad{
    [super viewDidLoad];
    if ([[[UIDevice currentDevice] systemVersion] floatValue] < 6.0)
        [[UIApplication sharedApplication] setStatusBarOrientation:UIDeviceOrientationLandscapeLeft animated:NO];    
}

Analogically, after you leave the LANDSCAPE controller, whatever controller you load, you should force again autorotation for IOS 5, but now you will use UIDeviceOrientationPortrait, as you go to a PORTRAIT controller:

- (void)viewDidLoad{
        [super viewDidLoad];
        if ([[[UIDevice currentDevice] systemVersion] floatValue] < 6.0)
            [[UIApplication sharedApplication] setStatusBarOrientation:UIDeviceOrientationPortrait animated:NO];    
    }

Now the last thing (and it’s a bit weird) – you have to change the way you switch from a controller to another, depending on the IOS:

Make an NSObject class “Schalter” (“Switch” from German).

In Schalter.h say:

#import <Foundation/Foundation.h>

@interface Schalter : NSObject
+ (void)loadController:(UIViewController*)VControllerToLoad andRelease:(UIViewController*)VControllerToRelease;
@end

In Schalter.m say:

#import "Schalter.h"
#import "AppDelegate.h"

@implementation Schalter
+ (void)loadController:(UIViewController*)VControllerToLoad andRelease:(UIViewController*)VControllerToRelease{

    //adjust the frame of the new controller
    CGRect statusBarFrame = [[UIApplication sharedApplication] statusBarFrame];
    CGRect windowFrame = [[UIScreen mainScreen] bounds];
    CGRect firstViewFrame = CGRectMake(statusBarFrame.origin.x, statusBarFrame.size.height, windowFrame.size.width, windowFrame.size.height - statusBarFrame.size.height);
    VControllerToLoad.view.frame = firstViewFrame;

    //check version and go
    if (IOS_OLDER_THAN_6)
        [((AppDelegate*)[UIApplication sharedApplication].delegate).window addSubview:VControllerToLoad.view];
    else
        [((AppDelegate*)[UIApplication sharedApplication].delegate).window setRootViewController:VControllerToLoad];

    //kill the previous view controller
    [VControllerToRelease.view removeFromSuperview];
}
@end

NOW, this is the way you use Schalter ( suppose you go from Warehouse controller to Products controller ) :

#import "Warehouse.h"
#import "Products.h"

@implementation Warehouse
Products *instance_to_products;

- (void)goToProducts{
    instance_to_products = [[Products alloc] init];
    [Schalter loadController:instance_to_products andRelease:self];
}

bla-bla-bla your methods

@end

Of course you must release instance_to_products object:

- (void)dealloc{
     [instance_to_products release];
     [super dealloc];
}

Well, this is it. Don’t hesitate to downvote, I don’t care. This is for the ones who are looking for solutions, not for reputation.
Cheers!
Sava Mazare.