Preferences are pieces of information that you store persistently and use to configure your app. Apps often expose preferences to users so that they can customize the appearance and behavior of the app. Most preferences are stored locally using the Cocoa preferences system—known as the user defaults system. Apps can also store preferences in a user’s iCloud account using the key-value store.

The user defaults system and key-value store are both designed for storing simple data types—strings, numbers, dates, Boolean values, URLs, data objects, and so forth—in a property list. The use of a property list also means you can organize your preference data using array and dictionary types. It is also possible to store other objects in a property list by encoding them into an NSData object first.

At a Glance

/office-email-mac-app.html. Like iOS’s built-in Settings app, the System Preferences application on OS X lets you customize the various aspects of your Mac to your liking. For instance, you can adjust the size and location of the Dock, select a desktop background, set your computer’s clock to a different time zone, customize how your keyboard, mouse and trackpad work. Perhaps the hardest thing to figure out when trying to move an app and its settings to another Mac is to find the application’s preferences, which are usually located in the Preferences folder.

Apps integrate preferences in several ways, including programmatically at various points throughout your code and as part of the user interface. Preferences are supported in both iOS and Mac apps.

You Decide What Preferences You Want to Expose

Preferences are different for each app, and it is up to you to decide what parts of your app you want to make configurable. Configuration involves checking the value of a stored preference from your code and taking action based on that value. Thus, the preference value itself should always be simple and have a specific meaning that is then implemented by your app.

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Relevant section:What Makes a Good Preference?

Apps Provide Their Own Preferences Interface

Because each app’s preferences are different, the app itself is responsible for deciding how best to present those preferences to the user, if at all. Both iOS and OS X provide some standard places for you to incorporate a preferences interface, but you are still responsible for designing that interface and displaying it at the appropriate time.

Apps Access Preferences Using the User Defaults Object

Apps access locally stored preferences using a user defaults object, which is either an NSUserDefaults object (iOS and OS X) or an NSUserDefaultsController object (OS X only). In addition to retrieving preference values, apps can use this object to register default values for preferences and manage other aspects of the preferences system.

Relevant chapter:Accessing Preference Values

iCloud Stores Shared Preference and Configuration Data

Apps that support iCloud can put some of their preference data in the user’s iCloud account and make it available to instances of the app running on the user’s other devices. You use this capability to supplement (not replace) your app’s existing preferences data and provide a more coherent experience across the user’s devices. For example, a magazine app might store information about the page number and issue last read by the user so that the app running on a different device can show that same page.

Defaults Are Grouped into Domains in OS X

OS X preferences are grouped by domains so that system preferences can be differentiated from app preferences. Splitting preferences in this manner lets the user specify some preferences globally and then override one or more of those preferences inside an app.

Relevant section:The Organization of Preferences

A Settings Bundle Manages Preferences for iOS Apps

An iOS, apps can display preferences from the Settings app, which is a good place to put preferences that the user does not need to configure frequently. To display preferences in the Settings app, an app’s bundle must include a special resource called a Settings bundle that defines the preferences to display, the proper way to display them, and the information needed to record the user’s selections.

Note: Apps are not required to use a Settings bundle to manage all preferences. For preferences that the user is likely to change frequently, the app can display its own custom interface for managing those preferences.

Relevant chapter:Implementing an iOS Settings Bundle

Safari Preferences Mac

See Also

For information about property lists, see Property List Programming Guide.

For more advanced information about using Core Foundation to manage preferences, see Preferences Programming Topics for Core Foundation.

Copyright © 2013 Apple Inc. All Rights Reserved. Terms of Use Privacy Policy Updated: 2013-10-22

You can change a number of settings to customize the Finder itself. From the Finder menu, click Finder and choose the Preferences menu item to display the Finder Preferences dialog box that you see in Figure 1.

Figure 1: You can configure Finder preferences here.

In the General section, the preference settings include

• Displaying icons on the Desktop: Enable these check boxes to display your hard disks, removable volumes (including CDs, DVDs, and Zip disks), and connected network servers.

• New Finder Windows Open: Click the drop-down list box to specify the spot where a new Finder window should open. By default, a new window displays the contents of your Home folder.

• Always Open Folders in a New Window: When this check box is enabled, double-clicking a folder will open it in a new Finder window, as did earlier versions of Mac OS. (If disabled, the contents of the folder appear in the same Finder window, which makes it easier to focus on just the folder you need at the moment.)

• Open New Windows in Column View: When you enable this check box, each new Finder window that you open automatically uses column view. (If disabled, the new window uses the last view mode you used.)

• Spring-loaded Folders and Windows: It sounds a little wacky, but using this feature can definitely speed up file copying. If this check box is enabled, you can drag an item on top of a folder — without releasing the mouse button — and after a preset time (controlled by the Delay slider), a spring-loaded window appears to show you the folder’s contents. At that point, you can either release the mouse button to drop the file inside the folder (upon which the window disappears), or you can drag the icon on top of another subfolder to spring it forth and drill even deeper.

Pssst. Hovering over a folder and pressing the spacebar makes the folder spring open immediately. Pass it on.

The Labels preference panel is a simple one — just click next to each label color to type your own text for that label.

From the Sidebar preferences panel, you can choose which default items should appear in the Finder window Sidebar column. Your choices include locations (like your Home and Applications folders), network servers, removable media, the Desktop itself, and — naturally — your hard drives. To add a default item to the Sidebar column, select the corresponding check box to enable it or disable the check box to banish that item forthwith.

The Advanced preference settings include

Profiles Mac System Preferences

• Always Show File Extensions: If this check box is enabled, the Finder displays the file extensions at the end of filenames, à la Windows. This comes in handy for some applications, where everything from a document to a preference file to the application itself all share the same icon. However, if you find extensions distasteful, leave things set with the default of extensions off.

• Show Warning Before Emptying the Trash: By default, this check box is enabled, and Mac OS X displays a confirmation dialog box before allowing you to — in the words of Mac OS X patrons around the world — toss the Bit Bucket. If you’re interested in speed and trust your judgment (and your mouse finger), you can disable this setting.

After you make the desired changes to the Finder Preferences, click the dialog box’s Close button to save your settings and return to the Finder.