C H A P T E R 8
User Input
Command-click to select other objects. If the objects have a defined order, Shift-click should result in a continuous selection and Command-click should provide a discontinuous selection. If the order is not defined, then both actions result in a discontinuous selection. Examples of continuous and discontinuous selections are shown in “Selection Methods” (page 109)
In a bitmap-based graphics document—in which images are a series of pixels rather than discrete objects—a user selects the range of pixels enclosed within a selection tool.
Editing Text
In addition to the methods for selecting text, there are a number of standard ways to edit text.
Inserting Text
To insert text, the user positions the insertion point by clicking where the text is to go, then starts typing. The application moves the insertion point to the right (or left, depending on the language) as each new character is added.
Applications with multiple-line text blocks should support word wrap, the automatic continuation of text from the end of one line to the beginning of the next without breaking in the middle of a word.
Deleting Text
When the user presses the Delete (or Backspace) key, one of two things happens:
■If text is selected, the entire selection is deleted.
■If there is no current selection, the character preceding the insertion point is deleted.
In either case, the insertion point replaces the deleted character or characters in the document. The deleted characters don’t go on to the Clipboard, but the user can undo the deletion by immediately choosing Undo from the Edit menu.
You can also implement the keyboard combination Option-Delete (or Option-Backspace) to delete the word that currently contains the insertion point or to delete the part of the word to the left of the insertion point. Be sure to document this behavior if you implement it.
If a keyboard has a Forward Delete (Fwd Del) key, the character following the insertion point is deleted each time the user presses the key.
Replacing a Selection
If the user starts typing when one or more characters are selected, the typed characters replace the selection. The deleted characters don’t go on to the Clipboard, but the user can undo the replacement by immediately choosing Undo from the Edit menu.
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C H A P T E R 8
User Input
Intelligent Cut and Paste
Intelligent cut and paste is a set of editing features that take into account the need for spaces between words. To understand why this feature is helpful, consider the following sequence of events in a text application without intelligent cut and paste:
1.A sentence in the user’s document reads
Returns are only accepted if the merchandise is damaged.
The user wants to change this to
Returns are accepted only if the merchandise is damaged.
2.The user selects the word only by double-clicking. The letters are highlighted, but neither adjacent space is selected.
3.The user chooses Cut from the Edit menu, clicks just before the word if, and chooses Paste.
4.The sentence now reads
Returns are accepted onlyif the merchandise is damaged.
To correct the sentence, the user has to remove the extra space between are and accepted, and add a space between only and if.
If your application supports intelligent cut and paste, follow these guidelines:
■If the user selects a word or a range of words, the selection itself is highlighted, but spaces adjacent to the selection are not highlighted.
■When the user chooses Cut, if the character preceding the selection is a space, cut that space along with the selection. If the character preceding the selection is not a space, but the character following the selection is a space, cut that space along with the selection.
■When the user chooses Paste, if the character to the left or right of the current selection is part of a word (but not inside a word), insert a space before pasting.
Use intelligent cut and paste only if the application supports the definition of a word as described in “What Constitutes a Word” (page 112) These rules apply to any selection consisting of one or more whole words, no matter how the user made the selection.
Note:Intelligent cut and paste doesn’t apply to all languages. Thai, Chinese, and Japanese, for example, don’t contain spaces.
Editing Text Fields
If your application isn’t primarily a text application, but it has text entry fields in dialogs, for example, you may not need to provide the full text-editing features described in this section. Ideally, an application that includes text editing should support the following features:
Editing Text |
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C H A P T E R 8
User Input
■The user can select the whole field and type in a new value, delete text, select a substring of the field and replace it, and select a word by double-clicking.
■The user can choose Undo, Cut, Copy, Paste, and Delete, as described in “The Edit Menu” (page 177)
■The application performs appropriate edit checks. For example, if the only legitimate value for a field is a string of digits, the application should alert the user if any nondigits are typed. For a more complete discussion of when to check for errors and apply changes in text fields, see “Accepting Changes” (page 235)
When possible, support automatically filling in text fields as users type. You might fill in a field with frequently typed information or information from a history list. If you do this, indicate what you are automatically filling in, perhaps by highlighting it, so it is clear what the user has typed and what information your application is providing.
If your application requires specific pieces of information from the user, you might assume that you should display an asterisk or custom icon next to each required text field and selection control. Doing so, however, can make your user interface appear cluttered and unappealing. To avoid this, begin by designing your user interface so that it’s easy for the user to comply with your requests. Then, if the user forgets to fill in a specific text field, you can display an asterisk or custom icon next to that field to draw attention to it. For example, if your application requires information to set up a service, make choices easy for the user by ensuring that radio buttons, pop-up menus, and other selection controls do not allow an empty selection. For text fields, wait until the user attempts to leave the current context (for example, by clicking Continue or OK), then display the “required” icon next to fields that are still empty. For some further guidelines on providing a good setup experience for your users, see “Setup Assistants ” (page 86)
Entering Passwords
When a user types a password into a text field, each typed character should appear as a bullet, matching the number of characters typed by the user. If the user deletes a character with the Delete key, one bullet is deleted from the text field and the insertion point moves back one bullet, as if the bullet represented an actual character. Double-clicking bulleted text in a password field selects all the bullets in the text field.
When the user leaves the text field (by pressing Tab, for example), the number of bullets in the text field should be modified so that the field does not reflect the actual number of characters in the password.
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2008-06-09 | © 1992, 2001-2003, 2008 Apple Inc. All Rights Reserved.