_____________________________________________________XawPlus

The List Widget

Application Header file
Class Header file
Class
Class Name
Superclass
<X11/XawPlus/List.h>
<X11/XawPlus/ListP.h>
ListWidgetClass
List
Simple

The List widget contains a list of strings formatted into rows and columns. When one of the strings is selected, it is highlighted, and the List widget's Notify action is invoked, calling all routines on its callback list. Only one string may be selected at a time.

Differences between Xaw and XawPlus

Since the core extension class Add3dExt is inserted, the List widget has the additional resources highlightColor, shadowColor and buttonBorderWidth. The default background color is now grey75.

Resources

When creating a List widget instance, the following resources are retrieved from the argument list of XtSetValues() or XtVaSetValues() or from the resource database:

Name Class RepType Default Value
OBJECT:
destroyCallback Callback Pointer NULL
RECTANGLE:
borderWidth
height
sensitive
width
x
y
BorderWidth
Height
Sensitive
Width
Position
Position
Dimension
Dimension
Boolean
Dimension
Position
Position
0
12
True
12
0
0
CORE:
border
background
mappedWhenManaged
BorderColor
Background
MappedWhenManaged
Pixel
Pixel
Boolean
XtDefaultForeground
grey75
True
ADD3DEXT:
highlightColor
shadowColor
buttonBorderWidth
Background
Background
Width
Pixel
Pixel
Dimension
grey90
grey40
2
SIMPLE:
cursor
cursorName
pointerColor
pointerColorBackground
insensitiveBorder
Cursor
Cursor
Foreground
Background
Insensitive
Cursor
String
Pixel
Pixel
Pixmap
left_ptr
NULL
XtDefaultForeground
XtDefaultBackground
NULL
LIST:
callback
pasteBuffer
foreground
font
internalHeight
internalWidth
defaultColumns
columnSpacing
rowSpacing
forceColumns
verticalList
list
longest
numberStrings
Callback
Boolean
Foreground
Font
Height
Width
Columns
Spacing
Spacing
Columns
Boolean
List
Longest
NumberStrings
XtCallbackList
Boolean
Pixel
XFontStruct *
Dimension
Dimension
int
Dimension
Dimension
Boolean
Boolean
String *
int
int
NULL
False
XtDefaultForeground
XtDefaultFont
2
4
2
6
4
False
False
NULL
0
0

callback All functions on this list are called whenever the notify action is invoked. The call_data argument contains information about the element selected and is described in detail in the List Callbacks section.
columnSpacing
rowSpacing
The amount of space, in pixels, between each of the rows and columns in the list.
defaultColumns The default number of columns. This value is used when neither the width nor the height of the List widget is specified or when forceColumns is True.
forceColumns Forces the default number of columns to be used regardless of the List widget's current size.
foreground A pixel value which indexes the widget's colormap to derive the color used to paint the text of the list elements.
internalHeight,
internalWidth
The margin, in pixels, between the edges of the list and the corresponding edge of the List widget's window.
list An array of text strings displayed in the List widget. If numberStrings is zero (the default) then the list must be NULL terminated. If a value is not specified for the list, then numberStrings is set to 1, and the name of the widget is used as the list, and longest is set to the length of the name of the widget. The list is used in place, and must be available to the List widget for the lifetime of this widget, or until it is changed with XtSetValues() or XawListChange(). Note that XtSetValues() only works well, if the memory location of the list structure changes. It is a good idea to use always XawListChange().
longest Specifies the width, in pixels, of the longest string in the current list. The List widget will compute this value if zero (the default) is specified. If this resource is not correctly specified, selection of list items may not work properly.
numberStrings The number of strings in the current list. If a value of zero (the default) is specified, the List widget will compute it. When computing the number of strings the List widget assumes that the list is NULL terminated.
pasteBuffer If this resource is set to True then the name of the currently selected list element will be put into CUT_BUFFER_0.
verticalList If this resource is set to True then the list elements will be presented in column major order.

List Actions

The List widget supports the following actions:

The following is the default translation table used by the List Widget:

The full list of actions supported by List widget is:

Set() Sets the list element that is currently under the pointer. To inform the user that this element is currently set, it is drawn with is foreground and background colors reversed. If this action is called when there is no list element under the cursor, the currently set element will be unset.
Unset() Cancels the set state of the element under the pointer, and redraws it with normal foreground and background colors.
Notify() Calls all callbacks on the List widget's callback list. Information about the currently selected list element is passed in the call_data argument (see List Callback below).

List Callbacks

All procedures on the List widget's callback list will have a XawListReturnStruct passed to them as call_data. The structure is defined in the List widget's application header file.

The list_index item used to be called simply index. Unfortunately, this name collided with a global name defined on some operating systems, and had to be changed.

Changing the List

To change the list that is displayed, use XawListChange():

Highlighting an Item

To highlight an item in the list, use XawListHighlight():

Only one item can be highlighted at a time. If an item is already highlighted when XawListHighlight() is called, the highlighted item is unhighlighted before the new item is highlighted.

Unhighlighting an Item

To unhighlight the currently highlighted item in the list, use XawListUnhighlight():

Retrieving the Currently Selected Item

To retrieve the list element that is currently set, use XawListShowCurrent().

XawListShowCurrent() returns a pointer to an XawListReturnStruct structure, containing the currently highlighted item. If the value of the index member is XAW_LIST_NONE, the string member is undefined, and no item is currently selected.

XawPlus_____________________________________________________