#If you're using storyboards...

If you're targeting OS X 10.10 and later (and using storyboards), you can use a custom NSStoryboardSegue to transition between view controllers. GRPushSegue implements this.

#GRNavigationController

Simple navigation controller, provides navigation to a stack of view controllers.

##Usage

Note: your view controllers must subclass GRViewController

###Setup

I recommend setting everything up in IB.

Here's what you must hook up:

1. view

   The view where the navigation controller will put it's contents

2. rootViewController

   The view controller added to the stack immediately after the navigation controller awakes, it's the first view controller

3. backButton

   An outlet to the button to use as the "back" button, this can be any subclass of NSControl (preferably NSButton or NSSegmentedControl).

###Pushing a view controller

// inside a subclass of GRViewController
[self.navigationController pushViewController:self.myOtherVC animated:YES]

###Popping the front view controller

// inside a subclass of GRViewController
[self.navigationController popViewControllerAnimated:YES]

##GRViewController

GRViewController is an abstract class, subclassed from NSViewController, which can be used inside GRNavigationControllers.

You use It just like a regular NSViewController but there are some additional methods you can override to control it's behavior on the navigation stack.

###Using a custom rewind transition

If you want your view controller to be popped using a specific transition, you can set It's rewindTransition property to a custom CATransition.

// inside a subclass of GRViewController

// create and set the custom transition
CATransition *rewind = [CATransition animation];
rewind.type = kCATransitionFade;
self.rewindTransition = rewind;

// pop
[self.navigationController popViewControllerAnimated:YES];

###Subclassing

There are 5 methods you can override to work with the navigation:

1. viewDidLoad

   Sent right after awakeFromNib

2. viewWillAppear

   Sent when the view is about to appear

3. viewDidAppear

   Sent when the view has just appeared

4. viewWillDisappear

   Sent when the view is about to disappear

5. viewDidDisappear

   Sent when the view has just disappeared

Note: viewWillAppear and viewWillDisappear occur inside a CATransaction, therefore any animations will be grouped with the navigation animation.

##Sample App: Countries

See the included sample app "Countries" for a complete example of how to use the navigation controller.

##Caveat

The superview of the navigation controller's view must be layer backed, which means anything inside the navigation must work in layer backed mode.

##Contributing

You can contribute with code, just send me a pull request, or open an issue for any bug/enhancement.

Disclaimer: sending a pull request does not mean I will accept It, if I don't accept your pull request It doesn't mean I don't love you ;)