Rob Seegel > Tk-MListbox-1.11 > Tk::MListbox

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Module Version: 1.11   Source  

NAME ^

Tk::MListbox - Multicolumn Listbox.

SYNOPSIS ^

  use Tk::MListbox;
  $ml = $parent->MListbox (<options>);

DESCRIPTION ^

Tk::MListbox is a multicolumn Listbox widget with builtin capabilites for sorting, resizing and repositioning of the columns.

Sorting is done by clicking on one of the column headings in the widget. The first click will sort the data with the selected column as key, a new click will reverse the sort order.

The columns may be resized by dragging a separator line which is drawn between each column.

A column's position in the widget might be changed by dragging it's heading left or right.

Tk::MListbox is used in a way similar to the standard Listbox, but in stead of scalar values MListbox operates on lists of data. In addition to methods for accessing the data in the MListbox, the widget offer methods for manipulation of the individual columns.

AUTHOR ^

Hans Jorgen Helgesen, hans_helgesen@hotmail.com (from March 2000: hans.helgesen@novit.no)

SEE ALSO ^

Tk::Listbox

STANDARD OPTIONS ^

-background -foreground -relief -takefocus -borderwidth -heigh -selectbackground -cursor -highlightbackground -selectborderwidth -xscrollcommand -exportselection -highlightcolor -selectforeground -yscrollcommand -font -highlightthickness -setgrid

See Tk::options for details of the standard options.

REQUIREMENTS ^

Tk::MListbox requires Tk::Pane. (and basic Perl/Tk of course....)

WIDGET SPECIFIC OPTIONS ^

-columns => list

Defines the columns in the widget. Each element in the list describes a column. See the COLUMNS section below.

-configurecommand => callback

The -configurecommand callback will be called whenever the layout of the widget has changed due to user interaction. That is, the user changes the width of a column by dragging the separator, or moves a column by dragging the column header.

This option is useful if the application wants to store the widget layout for later retrieval. The widget layout can be obtained by the callback by calling the method columnPackInfo().

-moveable => boolean

A value of 1 indicates that it is okay for the user to move the columns by dragging the column headers. 0 disables this function.

Default: 1

-resizeable => boolean

A value of 1 indicates that it is okay for the user to resize the columns by dragging the column separators. 0 disables this function.

Default: 1

Note that you can also specify -resizeable on a column by column basis. See the COLUMNS section below.

-selectmode => string

Should be "single", "browse", "multiple", or "extended".

Default is "browse". See Tk::Listbox.

-separatorcolor => string

Specifies the color of the separator lines (the vertical lines that separates the columns).

Default: black

Note that you can also specify -separatorcolor on a column by column basis. See the COLUMNS section below.

-separatorwidth => integer

Specifies the width in pixels of the separator lines (the vertical lines that separates the columns).

Default: 1

Note that you can also specify -separatorwidth on a column by column basis. See the COLUMNS section below.

-sortable => boolean

A value of 1 indicates that it is okay for the user to sort the data by clicking column headings. 0 disables this function.

Default: 1

Note that you can also specify -sortable on a column by column basis. See COLUMNS below.

COLUMNS ^

The MListbox widget is a collection of MLColumn widgets. Each MLColumn contains a Listbox, a heading and the separator bar. The columns are created and maintained through the -columns option or the column methods of the widget. The columns are indexed from 0 and up. Initially, column 0 is the leftmost column of the widget. The column indices are not changed when the columns are moved or hidden. The only ways to change the column indices are to call columnInsert(), columnDelete() or configure(-column).

Each column has its own set of options which might be passed to MListbox::configure(-columns), MListbox::insert(), MListbox::columnConfigure() or MLColumn::configure().

The following code snippets are all equal:

1. $ml=$mw->MListbox(-columns=>[[-text=>'Heading1', -sortable=>0], [-text=>'Heading2']]);

2. $ml=$mw->MListbox; $ml->columnInsert(0,-text=>'Heading1', -sortable=>0); $ml->columnInsert(0,-text=>'Heading2');

3. $ml=$mw->MListbox; $c=$ml->columnInsert(0,-text=>'Heading1'); $ml->columnInsert(0,-text=>'Heading2'); $c->configure(-sortable=>0);

4. $ml=$mw->MListbox; $ml->columnInsert(0,-text=>'Heading1'); $ml->columnInsert(0,-text=>'Heading2'); $ml->columnConfigure(0,-sortable=>0);

(See the columnConfigure() method below for details on column options).

All column methods expects one or two column indices as arguments. The column indices might be an integer (between 0 and the number of columns minus one), 'end' for the last column, or a reference to the MLColumn widget (obtained by calling MListbox->columnGet() or by storing the return value from MListbox->columnInsert()).

WIDGET METHODS ^

$ml->bindColumns(sequence,callback)

Adds the binding to all column headers in the widget. See the section BINDING EVENTS TO MLISTBOX below.

$ml->bindRows(sequence,callback)

Adds the binding to all listboxes in the widget. See the section BINDING EVENTS TO MLISTBOX below.

$ml->bindSeparators(sequence,callback)

Adds the binding to all separators in the widget. See the section BINDING EVENTS TO MLISTBOX below.

COLUMN METHODS

(Methods for accessing and manipulating individual columns in the MListbox widget)

$ml->columnConfigure(index,option=>value...)

Set option values for a specific column. Equal to $ml->columnGet(index)->configure(...).

The following column options are supported:

  • -comparecommand => callback

    Specifies a callback to use when sorting the MListbox with this column as key. The callback will be called with two scalar arguments, each a value from this particular column. The callback should return an integer less than, equal to, or greater than 0, depending on how the tow arguments are ordered. If for example the column should be sorted by numerical value:

        -comparecommand => sub { $_[0] <=> $_[1]}

    The default is to sort the columns alphabetically.

  • -text => string

    Specifies the text to be used in the heading button of the column.

  • -resizeable => boolean

    A value of 1 indicates that it is okay for the user to resize this column by dragging the separator. 0 disables this function.

    Default: 1

  • -separatorcolor => string

    Specifies the color of the separator line, default is black.

  • -separatorwidth => integer

    Specifies the width of the separator line in pixels. Default is 1.

  • -sortable => boolean

    A value of 1 indicates that it is okay for the user to sort the data by clicking this column's heading. 0 disables this function.

    Default: 1

$ml->columnDelete(first,last)

If last is omitted, deletes column first. If last is specified, deletes all columns from first to last, inclusive.

All previous column indices greater than last (or first if last is omitted) are decremented by the number of columns deleted.

$ml->columnGet(first,last)

If last is not specified, returns the MLColumn widget specified by first. If both first and last are specified, returns an array containing all columns from first to last.

$ml->columnHide(first,last)

If last is omitted, hides column first. If last is specified, hides all columns from first to last, inclusive.

Hiding a column is equal to calling $ml->columnGet(index)->packForget. The column is not deleted, all data are still available, and the column indices remain the same.

See also the columnShow() method below.

$ml->columnIndex(index)

Returns an integer index for the column specifed by index.

$ml->columnInsert(index,option=>value...)

Creates a new column in the MListbox widget. The column will get the index specified by index. If index is 'end', the new column's index will be one more than the previous highest column index.

If column index exists, the new column will be placed to the left of this column. All previous column indices equal to or greater than index will be incremented by one.

Returns the newly created MLColumn widget.

(See the columnConfigure() method above for details on column options).

$ml->columnPack(array)

Repacks all columns in the MListbox widget according to the specification in array. Each element in array is a string on the format index:width. index is a column index, width defines the columns width in pixels (may be omitted). The columns are packed left to right in the order specified by by array. Columns not specified in array will be hidden.

This method is most useful if used together with the columnPackInfo() method.

$ml->columnPackInfo

Returns an array describing the current layout of the MListbox widget. Each element of the array is a string on the format index:width (see columnPack() above). Only indices of columns that are currently shown (not hidden) will be returned. The first element in the returned array represents the leftmost column.

This method may be used in conjunction with columnPack() to save and restore the column configuration.

$ml->columnShow(index,option=>value)

Shows a hidden column (see the columnHide() method above). The column to show is specified by index.

By default, the column is pack'ed at the rigthmost end of the MListbox widget. This might be overridden by specifying one of the following options:

  • -after => index

    Place the column after (to the right of) the column specified by index.

  • -before => index

    Place the column before (to the left of) the column specified by index.

ROW METHODS

(Methods for accessing and manipulating rows of data)

Many of the methods for MListbox take one or more indices as arguments. See Tk::Listbox for a description of row indices.

$ml->delete(first,last)

Deletes one or more row elements of the MListbox. 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.

$ml->get(first,last)

If last is omitted, returns the content of the MListbox row indicated by first. If last is specified, the command returns a list whose elements are all of the listbox rows between first and last.

The returned elements are all array references. The referenced arrays contains one element for each column of the MListbox.

$ml->getRow(index)

In scalar context, returns the value of column 0 in the MListbox row specified by index. In list context, returns the content of all columns in the row as an array.

This method is provided for convenience, since retrieving a single row with the get() method might produce some ugly code.

The following two code snippets are equal:

   1. @row=$ml->getRow(0);

   2. @row=@{($ml->get(0))[0]};
$ml->sort(descending, columnindex...)

Sorts the content of the MListbox. If descending is a true value, the sort order will be descending. The default is ascending sort.

If columnindex is specified, the sort will be done with the specified column as key. You can specify as many columnindex arguments as you wish. Sorting is done on the first column, then on the second, etc...

The default is to sort the data on all columns of the listbox, with column 0 as the first sort key, column 1 as the second, etc.

OTHER LISTBOX METHODS ^

Most other Tk::Listbox methods works for the MListbox widget. This includes the methods activate, cget, curselection, index, nearest, see, selectionXXX, size, xview, yview.

See Tk::Listbox.

ADVERTISED SUBWIDGETS ^

pane

All MListbox columns are packed inside a Tk::Pane (this is done to enable horizontal scrolling).

Apart from "pane", the MListbox widget has no subwidgets, except for the variable number of MLColumns, which obviously cannot be advertised. The MLColumn widgets might be obtained by calling the columnGet() or columnInsert() methods.

The MLColumn widget (which represents a single column in the MListbox) advertises the following subwidgets:

listbox

The individual Listbox. Note that this is not the standard Tk::Listbox, but a derived version (CListbox). Several of the widget's methods will not work as expected.

separator

The column separator line. This is a Canvas.

heading

The column heading. This is a "HButton" (a Button with an additional -pixelwidth option).

frame

A Frame which contains the "listbox" and the "heading" subwidgets (but not the "separator").

Example: If you want to change the background color of the heading of column 4:

    $ml->columnGet(4)->Subwidget("heading")
        ->configure(-background=>'blue');

BINDING EVENTS TO MLISTBOX ^

Calling $ml->bind(...) probably makes little sense, since the call does not specify whether the binding should apply to the listbox, the header button or the separator line between each column.

In stead of the ordinary bind, the following methods should be used:

$ml->bind(sequence,callback)

Synonym for $ml->bindRows(sequence,callback).

$ml->bindRows(sequence,callback)

Synonym for $ml->bindSubwidgets('listbox',sequence,callback)

$ml->bindColumns(sequence,callback)

Synonym for $ml->bindSubwidgets('heading',sequence,callback)

$ml->bindSeparators(sequence,callback)

Synonym for $ml->bindSubwidgets('separator',sequence,callback)

$ml->bindSubwidgets(subwidget,sequence,callback)

Adds the binding specified by sequence and callback to all subwidgets of the given type (should be 'listbox', 'heading' or 'separator').

The binding is stored in the widget, and if you create a new column by calling $ml->columnInsert(), all bindings created by $ml->bindSubwidgets() are automatically copied to the new column.

The callback is called with the MListbox widget as first argument, and the index of the column where the event occured as the second argument.

NOTE that $ml->bindSubwidgets() does not support all of Tk's callback formats. The following are supported:

     \&subname
     sub { code }
     [ \&subname, arguments...]
     [ sub { code }, arguments...]

If sequence is undefined, then the return value is a list whose elements are all the sequences for which there exist bindings for subwidget.

If sequence is specified without callback, then the callback currently bound to sequence is returned, or an empty string is returned if there is no binding for sequence.

If sequence is specified, and callback is an empty string, then the current binding for sequence is destroyed, leaving sequence unbound. An empty string is returned.

An empty string is returned in all other cases.

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