Learning Cocoa

Chapter 1. Introduction to Cocoa

Cocoa is an extensive library of reusable software components used for building applications that run on Mac OS X. You can think of Cocoa as a large set of application building blocks that you can use “off the shelf” or adapt for your specific needs. This chapter gives you a high-level overview of those building blocks, shows you how they are organized, and explains the features they provide.

Cocoa poses a learning curve for newcomers, but once you learn to use it, application development will suddenly seem far easier and more fun. Because the Cocoa frameworks give you so much fundamental application functionality “for free,” you can spend your time and creative energy building new technology, not reinventing the wheel.

Cocoa has actually been around a long time—almost as long as the Macintosh itself. That’s because it is to a large extent based on OpenStep, which as NeXTSTEP was introduced in 1987. OpenStep evolved through many releases, was adopted by many companies as their development and deployment environment of choice, and received glowing reviews in the press. It was, and continues to be, solid technology, based on a design that was years ahead of anything else in the market and it has been perfected year after year.

Let’s take a closer look at Cocoa’s features and frameworks to give you a better idea of how to use Cocoa to create various applications. Figure 1.1 shows the general structure of the Mac OS X system software.

Figure 1-1. Cocoa ...