ref: 76b565d8b219c8db94a882e93725b4ab735414de
dir: /man/9/listbox/
.TH LISTBOX 9 .SH NAME listbox \- Create and manipulate listbox widgets .SH SYNOPSIS \f5listbox\fI \fIpathName \fR?\fIoptions\fR? .SH STANDARD OPTIONS .EX -background -highlightcolor -selectforeground -borderwidth -highlightthickness -takefocus -font -relief -width -foreground -selectbackground -xscrollcommand -height -selectborderwidth -yscrollcommand .EE .SH "WIDGET-SPECIFIC OPTIONS" .TP .B -height \fIdist\fP Specifies the desired height for the window. .TP .B -selectmode \fIval\fP 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 \f5single\fR, \f5browse\fR, \f5multiple\fR, or \f5extended\fR; the default value is \f5single\fR. .TP .B -width \fIdist\fP Specifies the desired width for the window. .SH DESCRIPTION The \f5listbox\fR command creates a new window (given by the \fIpathName\fR argument) and makes it into a listbox widget. Additional options, described above, may be specified on the command line to configure aspects of the listbox such as its colours, font, text, and relief. The \f5listbox\fR command returns its \fIpathName\fR argument. At the time this command is invoked, there must not exist a window named \fIpathName\fR. .PP 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. .PP 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 \f5-xscrollcommand\fR and \f5-yscrollcommand\fR options. .SH 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: .TP 12 \fInumber\fR Specifies the element as a numerical index, where 0 corresponds to the first element in the listbox. .TP 12 \f5active\fR Indicates the element that has the location cursor. This element will be displayed with a highlight rectangle when the listbox has the keyboard focus, and it is specified with the \f5activate\fR widget command. .TP 12 \f5anchor\fR Indicates the anchor point for the selection, which is set with the \f5selection anchor\fR widget command. .TP 12 \f5end\fR Indicates the end of the listbox. For some commands this means just after the last element; for other commands it means the last element. .TP 12 \f5@\fIx\f5,\fIy\fR Indicates the element that covers the point in the listbox window specified by \fIx\fR and \fIy\fR (in pixel coordinates). If no element covers that point, then the closest element to that point is used. .LP In the widget command descriptions below, arguments named \fIindex\fR, \fIfirst\fR, and \fIlast\fR always contain text indices in one of the above forms. .SH "WIDGET COMMAND" The \f5listbox\fR command creates a new Tk command whose name is \fIpathName\fR. This command may be used to invoke various operations on the widget. It has the following general form: .RS .EX \fIpathName option \fR?\fIarg arg ...\fR? .EE .RE \fIOption\fR and the \fIarg\fRs determine the exact behaviour of the command. The following commands are possible for listbox widgets: .TP \fIpathName \f5activate\fR \fIindex\fR Sets the active element to the one indicated by \fIindex\fR. The active element is drawn with an underline when the widget has the input focus, and its index may be retrieved with the index \f5active\fR. .TP \fIpathName \f5cget\fR \fIoption\fR Returns the current value of the configuration option given by \fIoption\fR. \fIOption\fR may have any of the values accepted by the \f5listbox\fR command. .TP \fIpathName \f5configure\fR ?\fIoption\fR? ?\fIvalue option value ...\fR? Query or modify the configuration options of the widget. If no \fIoption\fR is specified, returns a list of all of the available options for \fIpathName\fR. If one or more \fIoption-value\fR 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. \fIOption\fR may have any of the values accepted by the \f5listbox\fR command. .TP \fIpathName \f5curselection\fR 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. .TP \fIpathName \f5delete \fIfirst \fR?\fIlast\fR? Deletes one or more elements of the listbox. \fIFirst\fR and \fIlast\fR are indices specifying the first and last elements in the range to delete. If \fIlast\fR isn't specified it defaults to \fIfirst\fR, i.e. a single element is deleted. .TP \fIpathName \f5get \fIfirst\fR ?\fIlast\fR? If \fIlast\fR is omitted, returns the contents of the listbox element indicated by \fIfirst\fR. If \fIlast\fR is specified, the command returns a list whose elements are all of the listbox elements between \fIfirst\fR and \fIlast\fR, inclusive. Both \fIfirst\fR and \fIlast\fR may have any of the standard forms for indices. .TP \fIpathName \f5index \fIindex\fR Returns a decimal string giving the integer index value that corresponds to \fIindex\fR. .TP \fIpathName \f5insert \fIindex \fR?\fIelement element ...\fR? Inserts zero or more new elements in the list just before the element given by \fIindex\fR. If \fIindex\fR is specified as \f5end\fR then the new elements are added to the end of the list. Returns an empty string. .TP \fIpathName \f5nearest \fIy\fR Given a y-coordinate within the listbox window, this command returns the index of the (visible) listbox element nearest to that y-coordinate. .TP \fIpathName \f5see \fIindex\fR Adjust the view in the listbox so that the element given by \fIindex\fR 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. .TP \fIpathName \f5selection \fIoption arg\fR This command is used to adjust the selection within a listbox. It has several forms, depending on \fIoption\fR: .RS .TP \fIpathName \f5selection anchor \fIindex\fR Sets the selection anchor to the element given by \fIindex\fR. The selection anchor is the end of the selection that is fixed while dragging out a selection with the mouse. The index \f5anchor\fR may be used to refer to the anchor element. .TP \fIpathName \f5selection clear \fIfirst \fR?\fIlast\fR? If any of the elements between \fIfirst\fR and \fIlast\fR (inclusive) are selected, they are deselected. The selection state is not changed for elements outside this range. .TP \fIpathName \f5selection includes \fIindex\fR Returns 1 if the element indicated by \fIindex\fR is currently selected, 0 if it isn't. .TP \fIpathName \f5selection set \fIfirst \fR?\fIlast\fR? Selects all of the elements in the range between \fIfirst\fR and \fIlast\fR, inclusive, without affecting the selection state of elements outside that range. .RE .TP \fIpathName \f5size\fR Returns a decimal string indicating the total number of elements in the listbox. .TP \fIpathName \f5xview \fIargs\fR 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: .RS .TP \fIpathName \f5xview\fR 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 \f5-xscrollcommand\fR option. .TP \fIpathName \f5xview\fR \fIindex\fR Adjusts the view in the window so that the character position given by \fIindex\fR is displayed at the left edge of the window. Character positions are defined by the width of the character \f50\fR. .TP \fIpathName \f5xview moveto\fI fraction\fR Adjusts the view in the window so that \fIfraction\fR of the total width of the listbox text is off-screen to the left. \fIfraction\fR must be a fraction between 0 and 1. .TP \fIpathName \f5xview scroll \fInumber what\fR This command shifts the view in the window left or right according to \fInumber\fR and \fIwhat\fR. \fINumber\fR must be an integer. \fIWhat\fR must be either \f5units\fR or \f5pages\fR. If \fIwhat\fR is \f5units\fR, the view adjusts left or right by \fInumber\fR character units (the width of the \f50\fR character) on the display; if it is \f5pages\fR then the view adjusts by \fInumber\fR screenfuls. If \fInumber\fR is negative then characters farther to the left become visible; if it is positive then characters farther to the right become visible. .RE .TP \fIpathName \f5yview \fI?args\fR? 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: .RS .TP \fIpathName \f5yview\fR 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 \f5-yscrollcommand\fR option. .TP \fIpathName \f5yview\fR \fIindex\fR Adjusts the view in the window so that the element given by \fIindex\fR is displayed at the top of the window. .TP \fIpathName \f5yview moveto\fI fraction\fR Adjusts the view in the window so that the element given by \fIfraction\fR appears at the top of the window. \fIFraction\fR 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. .TP \fIpathName \f5yview scroll \fInumber what\fR This command adjusts the view in the window up or down according to \fInumber\fR and \fIwhat\fR. \fINumber\fR must be an integer. \fIWhat\fR must be either \f5units\fR or \f5pages\fR. If \fIwhat\fR is \f5units\fR, the view adjusts up or down by \fInumber\fR lines; if it is \f5pages\fR then the view adjusts by \fInumber\fR screenfuls. If \fInumber\fR is negative then earlier elements become visible; if it is positive then later elements become visible. .RE .SH "DEFAULT BINDINGS" If the selection mode is \f5single\fR or \f5browse\fR, 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 \f5browse\fR mode it is also possible to drag the selection with button 1. .PP If the selection mode is \f5multiple\fR or \f5extended\fR, any number of elements may be selected at once, including discontiguous ranges. In \f5multiple\fR mode, clicking button 1 on an element toggles its selection state without affecting any other elements. In \f5extended\fR 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. .PP Most people will probably want to use \f5browse\fR mode for single selections and \f5extended\fR mode for multiple selections; the other modes appear to be useful only in special situations. .PP The behaviour of listboxes can be changed by defining new bindings for individual widgets. The default bindings do a grab set when button 1 is pressed and a grab release when button 1 is released. Care must be taken when overriding either or both of these defaults to ensure that grabbing is consistent. .SH BUGS At least one entry is required for the widget to indicate that it has keyboard focus. .SH SEE ALSO .IR options (9), .IR types (9)