Managing separation and collapsing of the new UISplitViewController in iOS 8

UISplitViewControllerDelegateService.m

#import "UISplitViewControllerDelegateService.h"
#import "NoteViewController.h"

@interface UISplitViewControllerDelegateService () <UISplitViewControllerDelegate>

@end

@implementation UISplitViewControllerDelegateService

- (id)initWithSplitViewController:(UISplitViewController *)controller {
    
    self = [super init];
    if (!self) {
        return nil;
    }
    
    self.splitViewController = controller;
    controller.delegate = self;
    
    return self;
    
}

#pragma mark - Split view

- (BOOL)splitViewController:(UISplitViewController *)splitViewController collapseSecondaryViewController:(UIViewController *)secondaryViewController ontoPrimaryViewController:(UIViewController *)primaryViewController {
    
    if ([secondaryViewController isKindOfClass:[UINavigationController class]]
        && [[(UINavigationController *)secondaryViewController topViewController] isKindOfClass:[NoteViewController class]]
        && ([(NoteViewController *)[(UINavigationController *)secondaryViewController topViewController] note] == nil)) {
        // If the detail controller doesn't have an item, display the primary view controller instead
        return YES;
    }

    return NO;
    
}

- (UIViewController *)splitViewController:(UISplitViewController *)splitViewController
separateSecondaryViewControllerFromPrimaryViewController:(UIViewController *)primaryViewController{
    
    if ([primaryViewController isKindOfClass:[UINavigationController class]]) {
        for (UIViewController *controller in [(UINavigationController *)primaryViewController viewControllers]) {
            if ([controller isKindOfClass:[UINavigationController class]] && [[(UINavigationController *)controller visibleViewController] isKindOfClass:[NoteViewController class]]) {
                return controller;
            }
        }
    }
    
    // No detail view present
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    UINavigationController *detailView = [storyboard instantiateViewControllerWithIdentifier:@"detailView"];
    
    // Ensure back button is enabled
    UIViewController *controller = [detailView visibleViewController];
    controller.navigationItem.leftBarButtonItem = self.splitViewController.displayModeButtonItem;
    controller.navigationItem.leftItemsSupplementBackButton = YES;

    return detailView;
    
}

@end

What does your UISplitViewControllerDelegateService.h inherit from?

Sorry, just saw this - NSObject.