C H A P T E R 8

User Input

Home, End

Pressing the Home key is equivalent to moving the scrollers all the way to the top and to the left. In a text document, for example, pressing Home scrolls to the beginning of the document; in a spreadsheet, it may scroll to the beginning of the spreadsheet or to the beginning of a row. These keys should also work in scrolling lists to display the top or bottom of the list.

End is the opposite of Home: It scrolls to the end of a document.

If the beginning or end of the document is already reached, pressing Home or End produces a system alert sound. Pressing the Home or End key has no effect on the location of the insertion point or selected data.

Page Up, Page Down

Pressing Page Up or Page Down scrolls the document up or down one page. If an entire page can’t be displayed in the window, these keys first scroll incrementally up or down, until the top or bottom of the page is visible, before scrolling to the next page. These keys should also work in scrolling lists.

If the beginning or end of the document is reached, pressing Page Up or Page Down produces a system alert sound. Pressing the Page Up or Page Down key has no effect on the location of the insertion point or selected data.

Keyboard Shortcuts

Keyboard shortcuts are used throughout Mac OS X to provide quick ways for users to initiate certain actions. Many are provided by the operating system to meet both general usability needs and accessibility needs. The operating system therefore reserves certain keys and keyboard combinations for its use. These combinations, listed in Table 8-3 and Table 8-4 affect all applications and should not be used for any other function. Other keyboard shortcuts are used by the Universal Access features in Mac OS X and should be avoided.

In addition to the keyboard shortcuts reserved by the system, there are a large number of keyboard shortcuts that have a well established meaning, such as Command-S for Save and Command-Q for Quit. Users accustomed to running applications in Mac OS X expect these keyboard shortcuts to be available and to mean the same thing in each application they use. An application that overrides these shortcuts, such as one that uses Command-Q for a Query command instead of Quit, runs the risk of unnecessarily confusing and frustrating its users.

These common keyboard shortcuts are not reserved by the system, but they are highly recommended for applications that offer the associated commands. If your application does not offer all of these common commands, be sure you don't override these keyboard shortcuts and associate them with other commands your application does implement. A complete list of both system-reserved and commonly used keyboard shortcuts in Mac OS X is provided in “Keyboard Shortcuts Quick Reference” (page 355)

You may also define keyboard shortcuts in your application for frequently used commands. Some guidelines on how to create appropriate shortcuts are in “Creating Your Own Keyboard Shortcuts” (page 105) Other sections of this document list recommended keyboard shortcuts, where appropriate, to help you provide a consistent and familiar user experience in your application.

Reserved Keyboard Shortcuts

Don’t use the keys and key combinations in Table 8-3 for actions other than those listed in the table.

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C H A P T E R 8

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Table 8-3 Keyboard shortcuts reserved by the operating system

Mac OS X also provides full keyboard access mode, in which users can navigate through windows and dialogs. Whenthismodeisactive,otherkeyboardcombinationsmaybereservedbydefault. (See AccessibilityOverview.)

Important: Your application should not override the implementation of keyboard focus and navigation in Mac OS X. These features provide functionality for users with special needs.

Table 8-4 shows several key combinations that are reserved for use with localized versions of system software, localized keyboards, keyboard layouts, and input methods. These key combinations don’t correspond directly to menu commands.

2008-06-09 | © 1992, 2001-2003, 2008 Apple Inc. All Rights Reserved.

C H A P T E R 8

User Input

Creating Your Own Keyboard Shortcuts

Apple may reserve other keyboard shortcuts in the future, so be careful about adding your own. Before you consider creating a keyboard shortcut, be sure to look at the keyboard shortcuts listed in “Keyboard Shortcuts Quick Reference” (page 355) so you can avoid overriding the shortcuts users already know.

You might also consider examining the keyboard shortcuts used in other applications that target the same user audience your application targets. If your users are likely to be familiar with these other applications, you should try to avoid overriding the shortcuts they're used to using.

You should provide keyboard shortcuts onlyforfrequentlyusedcommands, not for every command. Presenting the user with too many keyboard shortcuts can be overwhelming and can make an application's user interface seem difficult to learn.

Use the Command key as the main modifier key for keyboard equivalents. For a command that complements another more common command, you can add Shift. The table below shows some recommended keyboard equivalents using Shift and their relation with the command they complement.

Table 8-5 Recommended keyboard shortcuts using Shift to complement other commands

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C H A P T E R 8

User Input

Note:Command-Shift-Z would be used for Redo only if Undo and Redo are separate commands (rather than toggled using Command-Z).

If there’s a third, less common command that’s related to a pair of commands that use Command and Command-Shift,youcanuseCommand-Optionforthethirdcommand’skeyboardequivalent. Intheexample in Table 8-6 Save All could be a dynamic menu item (see “Naming Menu Items” (page 163)) that appears in place of Save when the user presses the Option key (rather than a separate menu item). Use combinations like these very rarely.

Table 8-6 Example of using Option to modify a shortcut already using Command

Keys Command

Command-S Save

Command-Shift-S Save As

Command-Option-S Save All

Also use Option for a keyboard shortcut that is a convenience or power-user feature. For example, the Finder uses Command-Option-W for Close All Windows and Command-Option-M for Minimize All Windows.

Because the Control key is already used by some of the universal access features as well as in Cocoa text fields where Emacs-style key bindings are often used, it should be used as a modifier key only when necessary.

Remember that other languages may require modifier keys to generate certain characters. For example, on a French keyboard, Option-5 generates the “{“ character. You can safely use the Command key as a modifier, but avoid using Command and an additional modifier with characters not available on all keyboards. If you must use a modifier key in addition to the Command key, try to use it only with the alphabetic characters (a through z).

When adding custom keyboard shortcuts, try to avoid shortcuts that add a modifier key (such as Option or Shift) to an existing shortcut if the shortcuts have an unrelated function. For example, don’t use Shift-Command-Z as a keyboard shortcut for a command that is unrelated to Undo. Using that shortcut for Redo is appropriate, but using it for something like Calculate or Check Mail is confusing. If you can’t find a unique and easy-to-use keyboard shortcut for a command, don’t use one at all; keep in mind that users may have difficulty pressing multiple modifier keys anyway.

User-Defined Keyboard Shortcuts

Users may modify your application’s keyboard shortcuts and some of the system in Keyboard & Mouse preferences. Even though users can remap keyboard shortcuts, you should adhere to the shortcuts recommendedthroughoutthisdocument. Doingsoprovidesamoreconsistentuserexperience. See “Keyboard Shortcuts Quick Reference” (page 355) for a list of all the reserved and recommended combinations.

2008-06-09 | © 1992, 2001-2003, 2008 Apple Inc. All Rights Reserved.