The word document has a number of meanings, so a few words about its use in the title of this chapter and Chapter 16, “Working with OS X Documents,” are in order. In this chapter, document means a class that you create as a subclass of
UIDocument, which is part of the Cocoa Touch framework. In Chapter 16, document means a subclass of
NSDocument that you create.
UIDocument are similar but different, just as are Cocoa and Cocoa Touch. Fundamentally, the differences are between laptop and desktop computers with keyboards and trackpads on the one side and mobile devices with touchscreens on the other side.
This distinction is important for developers but is not even noticed by most users. Most of those ...