Cocoa in a Nutshell

Bundles and Resource Management

A bundle is an abstraction that represents a collection of resources, such as image files, nib files, or loadable code, stored within a folder. Bundles are used pervasively in Mac OS X—applications are themselves bundles, as are preference pane and screensaver modules and application plug-ins. Although bundles are directories, the Finder often presents them to the user as a single file. For a more in-depth discussion of bundles and their usage in Mac OS X, see Inside Mac OS X: System Overview (/Developer/Documentation/Essentials/SystemOverview/SystemOverview.pdf ).

NSBundle provides an interface to bundles in the filesystem. Every Cocoa application has at least one bundle—the main bundle, accessed using the mainBundle method—that represents the application. To load other bundles, use the methods initWithPath: or bundleWithPath:. To access a bundle containing a given class, use bundleForClass:.

Loading Resources

Using NSBundle , you can obtain the paths to resources without knowledge of a bundle’s internal directory structure or what localization is used. Methods that find a resource come in two flavors: those that retrieve individual resources, whose names are on the base method name pathForResource:ofType:, and those that return all resources of a type, which are based on the method name pathsForResourceOfType:. The paths returned by these methods are absolute paths in the filesystem. For example, consider the method pathForResource:ofType:. Given ...