CustomNavigationViewController.h

//
//  CustomNavViewController.h
//
//
//  Created by Ben Ford on 11/28/12.
//  Copyright (c) 2012 Ben Ford. All rights reserved.
//

#import <UIKit/UIKit.h>

typedef enum {
    NavigationDirectionLeft,
    NavigationDirectionRight,
} NavigationDirection;

@interface CustomNavigationViewController : UIViewController

@property (nonatomic, retain) UIImage *backgroundImage;

- (void)pushViewController:(UIViewController *)childViewController direction:(NavigationDirection)navigationDirection animated:(BOOL)animated;
- (void)popViewControllerAnimated:(BOOL)animated;
@end

CustomNavigationViewController.m

//
//  CustomNavViewController.m
//
//
//  Created by Ben Ford on 11/28/12.
//  Copyright (c) 2012 Ben Ford. All rights reserved.
//
#import "CustomNavigationViewController.h"

#define kAnimationSpeed 0.35f

@interface CustomNavigationViewController ()

@end

@implementation CustomNavigationViewController
{
    UIImageView *backgroundImageView;

    NSMutableArray *childViewControllers;
    NSMutableArray *pushDirections;
}

- (id)init {
    if( (self = [super init]) ) {
        childViewControllers = [[NSMutableArray alloc] init];
        pushDirections = [[NSMutableArray alloc] init];
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    if (self.backgroundImage) {
        backgroundImageView = [[UIImageView alloc] initWithImage:self.backgroundImage];
        [self.view addSubview:backgroundImageView];
    }
}

- (void)setBackgroundImage:(UIImage *)backgroundImage
{
    _backgroundImage = backgroundImage;
    
    if (backgroundImageView) {
        backgroundImageView.image = backgroundImage;
    }
}

- (void)pushViewController:(UIViewController *)newViewController direction:(NavigationDirection)navigationDirection animated:(BOOL)animated {
    
    // setup
    UIViewController *oldViewController = [childViewControllers lastObject];
    
    [childViewControllers addObject:newViewController];
    [pushDirections addObject:[NSNumber numberWithInt:navigationDirection]];
    
    // step 1:
    [self addChildViewController:newViewController];
    [oldViewController willMoveToParentViewController:self];
    
    // step 2:
    if( animated == YES ) {
        
        CGFloat startX = navigationDirection == NavigationDirectionLeft ? self.view.frame.size.width : -self.view.frame.size.width;
        CGFloat endX = navigationDirection == NavigationDirectionLeft ? -self.view.frame.size.width : self.view.frame.size.width;
        
        newViewController.view.frame = CGRectMake(startX, 0, self.view.frame.size.width, self.view.frame.size.height);

        [self transitionFromViewController:oldViewController toViewController:newViewController duration:kAnimationSpeed options:0 animations:^{
            oldViewController.view.frame = CGRectMake(endX, 0, oldViewController.view.frame.size.width, oldViewController.view.frame.size.height);
            newViewController.view.frame = CGRectMake(0, 0, newViewController.view.frame.size.width, newViewController.view.frame.size.height);
        } completion:^(BOOL finished) {
            [oldViewController removeFromParentViewController];
            [newViewController didMoveToParentViewController:self];
        }];
    } else {
        newViewController.view.frame = self.view.bounds;
        [self.view addSubview:newViewController.view];
        
        [oldViewController.view removeFromSuperview];
        [oldViewController removeFromParentViewController];
    }
    
    // step 3:
    [newViewController didMoveToParentViewController:self];
}

- (void)popViewControllerAnimated:(BOOL)animated {

    // setup:
    UIViewController *oldViewController = [childViewControllers lastObject];
    [childViewControllers removeLastObject];
    
    UIViewController *newViewController = [childViewControllers lastObject];
    
    NavigationDirection removeDirection = (NavigationDirection)[[pushDirections lastObject] intValue];
    [pushDirections removeLastObject];
    
    // flip the directions so the animation goes the opposite way
    removeDirection = removeDirection == NavigationDirectionLeft ? NavigationDirectionRight : NavigationDirectionLeft;
    
    // step 1:
    [oldViewController willMoveToParentViewController:nil];
    if( newViewController != nil )
        [self addChildViewController:newViewController];
    
    // step 2:
    if( animated == YES ) {
        
        CGFloat startX = removeDirection == NavigationDirectionLeft ? self.view.frame.size.width : -self.view.frame.size.width;
        CGFloat endX = removeDirection == NavigationDirectionLeft ? -self.view.frame.size.width : self.view.frame.size.width;
        
        newViewController.view.frame = CGRectMake(startX, 0, newViewController.view.frame.size.width, newViewController.view.frame.size.height);
        
        [self transitionFromViewController:oldViewController toViewController:newViewController duration:kAnimationSpeed options:0 animations:^{
            oldViewController.view.frame = CGRectMake(endX, 0, oldViewController.view.frame.size.width, oldViewController.view.frame.size.height);
            newViewController.view.frame = CGRectMake(0, 0, newViewController.view.frame.size.width, newViewController.view.frame.size.height);
        } completion:^(BOOL finished) {
            [oldViewController removeFromParentViewController];
            [newViewController didMoveToParentViewController:self];
        }];
        
    } else {
        // step 3:
        newViewController.view.frame = self.view.bounds;
        [self.view addSubview:newViewController.view];
        
        [oldViewController.view removeFromSuperview];
        [oldViewController removeFromParentViewController];
    }
    
    
}
@end