listbox(3Tk) listbox(3Tk)
listbox - Create and manipulate listbox widgets
listbox pathName ?options?
background font relief takeFocus |
borderWidth height selectBackground width |
cursor highlightBackground selectBorderWidth xScrollCommand |
exportSelection highlightColor selectForeground yScrollCommand |
foreground highlightThickness setGrid
See the ``options'' manual entry for details on the standard options.
WIDGET-SPECIFIC OPTIONS
Name: height
Class: Height
Command-Line Switch:-height
Specifies the desired height for the window, in lines. If zero or |
less, then the desired height for the window is made just large |
enough to hold all the elements in the listbox.
Name: selectMode |
Class: SelectMode |
Command-Line Switch:-selectmode |
Specifies one of several styles for manipulating the selection. The|
value of the option may be arbitrary, but the default bindings |
expect it to be either single, browse, multiple, or extended; the |
default value is browse.
Name: width
Class: Width
Command-Line Switch:-width
Specifies the desired width for the window in characters. If the
font doesn't have a uniform width then the width of the character
``0'' is used in translating from character units to screen units. |
If zero or less, then the desired width for the window is made just |
large enough to hold all the elements in the listbox.
The listbox command creates a new window (given by the pathName argument)
and makes it into a listbox widget. Additional options, described above,
may be specified on the command line or in the option database to
configure aspects of the listbox such as its colors, font, text, and
relief. The listbox command returns its pathName argument. At the time
this command is invoked, there must not exist a window named pathName,
but pathName's parent must exist.
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listbox(3Tk) listbox(3Tk)
A listbox is a widget that displays a list of strings, one per line.
When first created, a new listbox has no elements. Elements may be added
or deleted using widget commands described below. In addition, one or
more elements may be selected as described below. If a listbox is
exporting its selection (see exportSelection option), then it will
observe the standard X11 protocols for handling the selection. Listbox
selections are available as type STRING; the value of the selection will |
be the text of the selected elements, with newlines separating the |
elements. |
It is not necessary for all the elements to be displayed in the listbox |
window at once; commands described below may be used to change the view |
in the window. Listboxes allow scrolling in both directions using the |
standard xScrollCommand and yScrollCommand options. They also support |
scanning, as described below. |
INDICES |
Many of the widget commands for listboxes take one or more indices as |
arguments. An index specifies a particular element of the listbox, in |
any of the following ways:
number Specifies the element as a numerical index, where 0
corresponds to the first element in the listbox.
active Indicates the element that has the location cursor. This |
element will be displayed with an underline when the listbox |
has the keyboard focus, and it is specified with the activate|
widget command.
anchor Indicates the anchor point for the selection, which is set |
with the selection anchor widget command.
end Indicates the end of the listbox. For some commands this
means just after the last element; for other commands it
means the last element.
@x,y Indicates the element that covers the point in the listbox |
window specified by x and y (in pixel coordinates). If no |
element covers that point, then the closest element to that |
point is used. |
In the widget command descriptions below, arguments named index, first, |
and last always contain text indices in one of the above forms.
The listbox command creates a new Tcl command whose name is pathName.
This command may be used to invoke various operations on the widget. It
has the following general form:
pathName option ?arg arg ...?
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listbox(3Tk) listbox(3Tk)
Option and the args determine the exact behavior of the command. The
following commands are possible for listbox widgets:
pathName activate index
Sets the active element to the one indicated by index. The active |
element is drawn with an underline when the widget has the input |
focus, and its index may be retrieved with the index active.
pathName bbox index
Returns a list of four numbers describing the bounding box of the |
text in the element given by index. The first two elements of the |
list give the x and y coordinates of the upper-left corner of the |
screen area covered by the text (specified in pixels relative to the|
widget) and the last two elements give the width and height of the |
area, in pixels. If no part of the element given by index is |
visible on the screen then the result is an empty string; if the |
element is partially visible, the result gives the full area of the |
element, including any parts that are not visible.
pathName cget option
Returns the current value of the configuration option given by |
option. Option may have any of the values accepted by the listbox |
command.
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no
option is specified, returns a list describing all of the available
options for pathName (see Tk_ConfigureInfo for information on the
format of this list). If option is specified with no value, then
the command returns a list describing the one named option (this
list will be identical to the corresponding sublist of the value
returned if no option is specified). If one or more option-value
pairs are specified, then the command modifies the given widget
option(s) to have the given value(s); in this case the command
returns an empty string. Option may have any of the values accepted
by the listbox command.
pathName curselection
Returns a list containing the numerical indices of all of the
elements in the listbox that are currently selected. If there are
no elements selected in the listbox then an empty string is
returned.
pathName delete first ?last?
Deletes one or more elements of the listbox. First and last are
indices specifying the first and last elements in the range to
delete. If last isn't specified it defaults to first, i.e. a single
element is deleted.
pathName get first ?last?
If last is omitted, returns the contents of the listbox element
indicated by first. If last is specified, the command returns a |
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listbox(3Tk) listbox(3Tk)
list whose elements are all of the listbox elements between first |
and last, inclusive. Both first and last may have any of the |
standard forms for indices.
pathName index index
Returns a decimal string giving the integer index value that
corresponds to index.
pathName insert index ?element element ...?
Inserts zero or more new elements in the list just before the |
element given by index. If index is specified as end then the new |
elements are added to the end of the list. Returns an empty string.
pathName nearest y
Given a y-coordinate within the listbox window, this command returns
the index of the (visible) listbox element nearest to that ycoordinate.
pathName scan option args
This command is used to implement scanning on listboxes. It has two
forms, depending on option:
pathName scan mark x y
Records x and y and the current view in the listbox window;
used in conjunction with later scan dragto commands. Typically
this command is associated with a mouse button press in the
widget. It returns an empty string.
pathName scan dragto x y.
This command computes the difference between its x and y
arguments and the x and y arguments to the last scan mark
command for the widget. It then adjusts the view by 10 times
the difference in coordinates. This command is typically
associated with mouse motion events in the widget, to produce
the effect of dragging the list at high speed through the
window. The return value is an empty string.
pathName see index
Adjust the view in the listbox so that the element given by index is|
visible. If the element is already visible then the command has no |
effect; if the element is near one edge of the window then the |
listbox scrolls to bring the element into view at the edge; |
otherwise the listbox scrolls to center the element.
pathName selection option arg
This command is used to adjust the selection within a listbox. It
has several forms, depending on option:
pathName selection anchor index
Sets the selection anchor to the element given by index. The
selection anchor is the end of the selection that is fixed
while dragging out a selection with the mouse. The index
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listbox(3Tk) listbox(3Tk)
anchor may be used to refer to the anchor element.
pathName selection clear first ?last?
If any of the elements between first and last (inclusive) are
selected, they are deselected. The selection state is not
changed for elements outside this range.
pathName selection includes index
Returns 1 if the element indicated by index is currently
selected, 0 if it isn't.
pathName selection set first ?last?
Selects all of the elements in the range between first and
last, inclusive, without affecting the selection state of
elements outside that range.
pathName size
Returns a decimal string indicating the total number of elements in
the listbox.
pathName xview args
This command is used to query and change the horizontal position of
the information in the widget's window. It can take any of the
following forms:
pathName xview
Returns a list containing two elements. Each element is a real
fraction between 0 and 1; together they describe the
horizontal span that is visible in the window. For example, if
the first element is .2 and the second element is .6, 20% of
the listbox's text is off-screen to the left, the middle 40% is
visible in the window, and 40% of the text is off-screen to the
right. These are the same values passed to scrollbars via the
-xscrollcommand option.
pathName xview index
Adjusts the view in the window so that the character position
given by index is displayed at the left edge of the window.
Character positions are defined by the width of the character
0.
pathName xview moveto fraction
Adjusts the view in the window so that fraction of the total
width of the listbox text is off-screen to the left. fraction
must be a fraction between 0 and 1.
pathName xview scroll number what
This command shifts the view in the window left or right
according to number and what. Number must be an integer. What
must be either units or pages or an abbreviation of one of
these. If what is units, the view adjusts left or right by
number character units (the width of the 0 character) on the
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listbox(3Tk) listbox(3Tk)
display; if it is pages then the view adjusts by number
screenfuls. If number is negative then characters farther to
the left become visible; if it is positive then characters
farther to the right become visible.
pathName yview ?args?
This command is used to query and change the vertical position of
the text in the widget's window. It can take any of the following
forms:
pathName yview
Returns a list containing two elements, both of which are real
fractions between 0 and 1. The first element gives the
position of the listbox element at the top of the window,
relative to the listbox as a whole (0.5 means it is halfway
through the listbox, for example). The second element gives
the position of the listbox element just after the last one in
the window, relative to the listbox as a whole. These are the
same values passed to scrollbars via the -yscrollcommand
option.
pathName yview index
Adjusts the view in the window so that the element given by
index is displayed at the top of the window.
pathName yview moveto fraction
Adjusts the view in the window so that the element given by
fraction appears at the top of the window. Fraction is a
fraction between 0 and 1; 0 indicates the first element in the
listbox, 0.33 indicates the element one-third the way through
the listbox, and so on.
pathName yview scroll number what
This command adjusts the view in the window up or down
according to number and what. Number must be an integer. What
must be either units or pages. If what is units, the view
adjusts up or down by number lines; if it is pages then the
view adjusts by number screenfuls. If number is negative then
earlier elements become visible; if it is positive then later
elements become visible.
DEFAULT BINDINGS
Tk automatically creates class bindings for listboxes that give them
Motif-like behavior. Much of the behavior of a listbox is determined by
its selectMode option, which selects one of four ways of dealing with the
selection.
If the selection mode is single or browse, at most one element can be
selected in the listbox at once. In both modes, clicking button 1 on an
element selects it and deselects any other selected item. In browse mode
it is also possible to drag the selection with button 1.
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listbox(3Tk) listbox(3Tk)
If the selection mode is multiple or extended, any number of elements may
be selected at once, including discontiguous ranges. In multiple mode,
clicking button 1 on an element toggles its selection state without
affecting any other elements. In extended mode, pressing button 1 on an
element selects it, deselects everything else, and sets the anchor to the
element under the mouse; dragging the mouse with button 1 down extends
the selection to include all the elements between the anchor and the
element under the mouse, inclusive.
Most people will probably want to use browse mode for single selections
and extended mode for multiple selections; the other modes appear to be
useful only in special situations.
In addition to the above behavior, the following additional behavior is |
defined by the default bindings:
[1] In extended mode, the selected range can be adjusted by pressing
button 1 with the Shift key down: this modifies the selection to
consist of the elements between the anchor and the element under the
mouse, inclusive. The un-anchored end of this new selection can
also be dragged with the button down.
[2] In extended mode, pressing button 1 with the Control key down starts
a toggle operation: the anchor is set to the element under the
mouse, and its selection state is reversed. The selection state of
other elements isn't changed. If the mouse is dragged with button 1
down, then the selection state of all elements between the anchor
and the element under the mouse is set to match that of the anchor
element; the selection state of all other elements remains what it
was before the toggle operation began.
[3] If the mouse leaves the listbox window with button 1 down, the
window scrolls away from the mouse, making information visible that
used to be off-screen on the side of the mouse. The scrolling
continues until the mouse re-enters the window, the button is
released, or the end of the listbox is reached.
[4] Mouse button 2 may be used for scanning. If it is pressed and
dragged over the listbox, the contents of the listbox drag at high
speed in the direction the mouse moves.
[5] If the Up or Down key is pressed, the location cursor (active
element) moves up or down one element. If the selection mode is
browse or extended then the new active element is also selected and
all other elements are deselected. In extended mode the new active
element becomes the selection anchor.
[6] In extended mode, Shift-Up and Shift-Down move the location cursor
(active element) up or down one element and also extend the
selection to that element in a fashion similar to dragging with
mouse button 1.
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listbox(3Tk) listbox(3Tk)
[7] The Left and Right keys scroll the listbox view left and right by
the width of the character 0. Control-Left and Control-Right scroll
the listbox view left and right by the width of the window.
Control-Prior and Control-Next also scroll left and right by the
width of the window.
[8] The Prior and Next keys scroll the listbox view up and down by one
page (the height of the window).
[9] The Home and End keys scroll the listbox horizontally to the left
and right edges, respectively.
[10] Control-Home sets the location cursor to the the first element in
the listbox, selects that element, and deselects everything else in
the listbox.
[11] Control-End sets the location cursor to the the last element in the
listbox, selects that element, and deselects everything else in the
listbox.
[12] In extended mode, Control-Shift-Home extends the selection to the
first element in the listbox and Control-Shift-End extends the
selection to the last element.
[13] In multiple mode, Control-Shift-Home moves the location cursor to
the first element in the listbox and Control-Shift-End moves the
location cursor to the last element.
[14] The space and Select keys make a selection at the location cursor
(active element) just as if mouse button 1 had been pressed over
this element.
[15] In extended mode, Control-Shift-space and Shift-Select extend the
selection to the active element just as if button 1 had been pressed
with the Shift key down.
[16] In extended mode, the Escape key cancels the most recent selection
and restores all the elements in the selected range to their
previous selection state.
[17] Control-slash selects everything in the widget, except in single and
browse modes, in which case it selects the active element and
deselects everything else.
[18] Control-backslash deselects everything in the widget, except in
browse mode where it has no effect.
[19] The F16 key (labelled Copy on many Sun workstations) or Meta-w
copies the selection in the widget to the clipboard, if there is a
selection.
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listbox(3Tk) listbox(3Tk)
The behavior of listboxes can be changed by defining new bindings for
individual widgets or by redefining the class bindings.
listbox, widget
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