Programmer's Reference
List widgets (CwList) present a list of items and allow the user
to select one or more items from the list. List widgets are created
using thecreateList:argBlock:and
createScrolledList:argBlock: convenience
methods. The latter method makes the list scrollable, but otherwise
provides basically the same functionality. Scrolled lists are discussed
on Scrolled lists.
The items in the list and the selected items are specified by the
items and selectedItems resources, respectively.
The selectionPolicy resource specifies the policy for selecting
items. It has four possible settings:
- XmBROWSESELECT
- Allows only single selection. Behavior might vary from platform to
platform, but normally the selection moves when the mouse is dragged.
This is the default selection policy.
- XmSINGLESELECT
- Allows only single selection. Behavior might vary from platform to
platform, but normally the selection remains the same when the mouse is
dragged.
- XmMULTIPLESELECT
- Allows multiple items to be selected. The selection of an item is
toggled when it is clicked on. Clicking on an item does not deselect
previously selected items.
- XmEXTENDEDSELECT
- Allows multiple items to be selected, either by dragging the selection or
by clicking on items with a modifier key held down. Behavior might vary
from platform to platform, but normally clicking on an item without a modifier
key held down deselects all previously selected items.
Tip: | On some platforms, browse select and single select work the same way.
|
List widgets provide several methods for adding, deleting and replacing
items and selected items in the list.
The selectionPolicy resource determines which callback is used
to notify the application of changes in the selection. List widgets
support the following callbacks:
- browseSelectionCallback
- Executed when an item is selected in browse selection mode
- singleSelectionCallback
- Executed when an item is selected in single selection mode
- multipleSelectionCallback
- Executed when an item or group of items is selected in multiple selection
mode
- extendedSelectionCallback
- Executed when an item or group of items is selected in extended selection
mode
- defaultActionCallback
- Executed when an item is double clicked (all modes)
The call data of the selection callback specifies the item or items that
were selected, and the position(s) of the selected item(s) in the list.
Item positions in the list are numbered starting from one.
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