Objective-C Programming: The Big Nerd Ranch Guide

Model-View-Controller

Model-View-Controller, or MVC, is a design pattern that is based on the idea that any class that you create should fall into one of three job categories: model, view, or controller. Here is a breakdown of the division of labor:

• Models are responsible for storing data and making it available to other objects. Models have no knowledge of the user interface or how to draw themselves on the screen; their sole purpose is holding and managing data. NSString, NSDate, and NSArray are traditional model objects. In iTahDoodle, the NSMutableArray where tasks are stored is a model object. Later, each individual task will be described in an instance of NSString, and these will also be model objects.

• Views are the ...