Developer Tools and Technologies
Cocoa Frameworks
AppKit is the core Cocoa framework for building Mac OS X graphical applications. The framework includes graphical controls such as windows, buttons, toolbars, and checkboxes—all easily accessible from Interface Builder.
The Cocoa frameworks handle all the details of your event-driven application for you, managing mouse clicks, formatting keyboard entry, and handling window arrangement. By using Cocoa and AppKit, your application will look and behave like a true Mac application.
Cocoa Touch Frameworks
For iPhone OS, the Cocoa Touch frameworks focus on touch-based interfaces and optimization. The UIKit provides the basic tools and infrastructure you need to implement graphical, event-driven applications in iPhone OS.
The unique interface of the iPhone means that Cocoa Touch has a unique design to match. Using UIKit you have access to the special GUI controls, buttons, and full-screen views on iPhone OS. You also get to control your application with the accelerometer and the multi-touch gesture.
Key Cocoa & Cocoa Touch Frameworks
Core Data
With Core Data you can easily create well-factored applications because it handles all the complexities of data management for you, such as document undo operations, or caching efficiently. It also provides pre-built controller objects which eliminates the need for much of the glue code between your application's user interface and its data model.
Core Animation
Create a rich cinematic experience with a minimum of code using Core Animation. It taps into the power of the Mac OS X graphics frameworks including QuickTime, Quartz, OpenGL and Quartz Composer, and unifies the power of all of these frameworks into a single easy-to-use developer interface.
Core Image
Core Image lets you easily create real-time image processing solutions that automatically take full advantage of the latest GPU and multi-core CPUs. Its built-in filter effects, such as blur/sharpen, color effects and distortions, let you perform graphical tasks with a minimum amount of coding.
QTKit
Access the core functionality of QuickTime with QTKit, so you can edit, splice, combine, and transcode QuickTime video content in your Cocoa application. The QTKit Capture API lets you capture video from DV and HDV cameras and more.
Core Audio
Core Audio makes it easy to add world-class audio features to your application using OpenAL for immersive audio in games, QuickTime audio for working with audio and video, and the Audio Hardware Abstraction Layer for interfacing with consumer and professional audio gear.
Foundation
The Foundation framework defines a base layer of classes for Objective-C programming, and provides the fundamental data types and essential services that underlie Cocoa.
The Cocoa and Cocoa Touch frameworks that power Mac OS X and iPhone OS are tightly integrated into the Xcode development experience. Cocoa's high-level APIs make it easy to add animation, networking, and the native platform appearance and behavior to your application with only a few lines of code.
Cocoa & Cocoa Touch Frameworks
The Cocoa frameworks consist of libraries, APIs, and runtimes that form the development layer for all of Mac OS X. By developing with Cocoa, you will be creating applications the same way Mac OS X itself is created. Your application will automatically inherit the great behaviors and appearances of Mac OS X, with full access to the underlying power of the UNIX operating system. Using Cocoa with the Xcode IDE is simply the best way to create native Mac applications.
For iPhone OS, the Cocoa Touch frameworks provide a similar set of functionality, tuned for the touch-based, mobile experience on iPhone.
Objective-C Gives Cocoa Its Flexibility
Much of Cocoa is implemented in Objective-C, an object-oriented programming language that uses a truly dynamic runtime to execute application events.
As your application runs, the Objective-C runtime instantiates objects based on executing logic—not just in ways defined during compilation. For example, a running Objective-C application can load an interface (a nib file created by Interface Builder), connect the Cocoa objects in the interface to your application code, then run the correct method once the UI button is pressed. No recompiling is necessary.
Because Objective-C is a superset of C, it is easy to mix C and even C++ into your Cocoa applications.
Objective-C’s dynamic runtime is similar to many modern scripting languages, making it easy to map Cocoa’s features to other languages using the Cocoa Bridge. With the Cocoa Bridge, developers can create first-class Mac OS X applications using AppleScript, Ruby, and Python.
Cocoa Uses the Model-View-Controller Design Pattern
Cocoa uses the Model-View-Controller (MVC) design pattern throughout. Models encapsulate application data, Views display and edit that data, and Controllers mediate the logic between the two. By separating responsibilities in this manner, you end up with an application that is easier to design, implement, and maintain.
The MVC pattern means that Interface Builder requires no code to be written or generated while you focus exclusively on the View of your application. Cocoa bindings on the Mac eliminate most of the glue code, making the connection between Controllers coded in Xcode and the Views designed within Interface Builder a simple matter of graphically “wiring” the two together. Interface Builder works with Cocoa to make localizing your application easy so you can quickly enter entirely new markets.
