Editable Collection

Examples: Context:  The user should build or modify an ordered set of things, possibly (but not necessarily) chosen from a larger set.

Problem:  How should the artifact indicate what the user is supposed to do with that collection?


Solution:  Show the collection to the user, along with obvious ways to remove or change the position of each item. To add an item, make it eminently clear whether the user should obtain the item before or after the "add" command or gesture.  Most of the time, this is clear from context -- if a user is shopping, obviously they have to pick the item out before they put it in their cart -- but other times it's not, so indicate it with a good metaphor, or good labeling (e.g. "Add..." with a subsequent dialog), or by the imposition of constraints (e.g. Disabled Irrelevant Things). If duplicate items in the collection aren't meaningful, then gently disallow them.

In a visually-oriented artifact, direct manipulation is an excellent way of dealing with addition, removal, and ordering. Today's desktop GUIs offer drag-and-drop for this. If you use it, be sure to (1) offer a "dumping ground" for removed items, such as the familiar Mac trash can, if they don't get returned to their source; and (2) give some visual indication that you can do this, if there's no strong cultural indication to do so. (Software that use D&D as their primary means of interaction, such as drawing programs, have such cultural indications; others generally don't.)

Notes:  Obtaining an item before or after the "add" gesture -- this is part of the old "noun-verb vs. verb-noun" debate. (Any takers?) A good reason to use "noun-verb" is multiple selection: if you want to add or remove multiple items, the user needs to be able to pick them first, then do the operation on them (see Actions for Multiple Objects).

Comments to:  jtidwell@alum.mit.edu
Last modified May 17, 1999

Copyright (c) 1999 by Jenifer Tidwell.  All rights reserved.