Understanding iPad Navigation
Although the iPhone and iPad are very similar, one area in which they really differ is in how a user can navigate through an application.
On the iPhone, a Back button is prominently displayed as the user moves from one view to another. (Figure 5-6 shows what I mean.) Having a Back button is, of course, a requirement for any application if you want the user to be able to navigate through the app’s functionality.
Apple has built this ability into the iOS architecture and has made it an integral part of the view controller architecture, as personified in the Navigation controller. (Okay, I know it isn’t a “person,” but you get the idea.)
A Navigation controller is a Container view controller that enables the user to navigate back and forth between view controllers. A Navigation controller is an instance of the
UINavigationController class, which is a class you use “as is” and don’t subclass. The methods of this class provide support for managing a stack-based collection of custom view controllers. This stack represents the path taken by the user through the application, with the bottom of the stack reflecting the starting point and the top of the stack reflecting the user’s current position in the application.