User Interface

The appearance and behaviour of the list can be modified significantly by the programmer but if used without any modification the list has an inherent look and feel. The default appearance uses lines, boxes, icons and text to provide a visually stimulating view of the list. There is an alternative look that borrows from what I presume is a Maclike look (aka, boring). What is described in detail here is the more adorned look.

The tree list has vertical and horizontal scrollbars with the obvious uses, these scroll the list itself which contains the items. Each item is either a root item (a list may have multiple roots), or a child item. Any item may itself be a parent to other child items. Any item that has children is displayed with a little exploder box that can be used to control whether its children are shown or hidden.

Individual items are shown as an icon as well as an optional text string. The icon is intended to indicate the type of the item in the same way as the browser does, unlike the browser the icon may be any size the programmer wishes, and sizes may be mixed within a list. The text string is intended to display the name of the icon. Selection affects the way the list items are shown. If it is selected then the icon is shown with subdued colors and the text is shown in inverted colors. In addition to selection (which may be multiple), the "current" item is indicated by drawing a samll marker to the left og the item. Only one item may be "current", and this is usually the last item clicked on. The notion of of the current item is that it is the focus of the list and any keyboard operations apply relative to that item.

The keyboard interface allows the list to be used by the mouse-impaired. This is a list of keys.

up-arrow, down-arrow
Move up and down the list (well, what did you expect?)
left-arrow, right-arrow
Explode and collapse children
enter
Invoke, the keyboard equivalent of double-clicking
space
Select, the keyboard equivalent of single-click
shift
Extend selection

alphabetic index hierarchy of classes


The TreeList Control Documentation, HTML Edition, for Release 1.1d8 of the Be OS.

Copyright © 1996 Designer Logic (xyzzy). All rights reserved.

Be, the Be logo, BeBox, Be OS, Be Operating System, and GeekPort are trademarks of Be, Inc.

Last modified December 31, 1996.

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