Each iOS application contains at least one instance of the
UIViewController interface that handles all view events and manages the application's business logic. This class provides the fundamental view-management model for all iOS apps. A view controller manages a set of views that make up a portion of your app's user interface. As part of the controller layer of your app, a view controller coordinates its efforts with model objects and other controller objects—including other view controllers—so your app presents a single coherent user interface.
The application that we are going to write will have only one view; that's why we choose a Single-View Application template to create one. This view will be used to present the rendered picture. Our
ViewController class will contain three major components that each AR application should have (see the next diagram):