MVC

Junior PRO

The point

MVC in Cocoa is not the "classic" Smalltalk MVC, and iOS interviews ask about Apple's variant:

• Model — data and business logic. Knows nothing about the UI.
• View — UIView and its subclasses. Shows what it is given and reports user actions (target-action, delegate). Knows nothing about the Model.
• Controller — UIViewController. The only one that knows both: reads the Model, configures the View, handles events and updates the Model.

The key difference from Smalltalk MVC: there the View observes the Model directly. In Apple's version View and Model do not know each other; only the Controller links them. So a Model is reusable with any UI, and a View with any data.