Question

The following code produces pretty much what I want, but the scrollable pane on the left doesn’t scroll. I am using ActivePerl 5.8.9 Build 825:

The code is:

use Tk;
use Tk::Pane;
use Tk::LabFrame;

# create the application window
my $MW = MainWindow->new ( -background => "GREY" );

# set the x/y size for the window
$MW->geometry("800x600");

# add a window title
$MW->title("Monitor Boxes");

# Disallow window resizing
$MW->resizable(0,0);

# create a labelled frame on the window to house the list of buttons to be pressed
$boxListFrame = &create_framed_section( "List Of Boxes", 
                    "acrosstop", 
                    5, 
                    5, 
                    170, 
                    565,
                    "BLUE", 
                    "GREY");

# create a labelled frame on the window to house the information to be displayed 
# when a particular button is pressed
$statusOfBoxFrame = &create_framed_section( "Status", 
                        "acrosstop", 
                        185, 
                        5, 
                        600, 
                        565, 
                        "BLUE", 
                        "GREY");

# create a scrollable pane in the left hand pane so that if more buttons than 
# is able to be displayed are put onto the application the scroll bar will allow 
# the ones not displayed to be access
my $pane = $MW->Scrolled(   'Pane', 
                -scrollbars => 'e', 
                -width => 140, 
                -height => 555, 
                -background => "GREY")->place(-x=>15,-y=>25);

# setup the array of buttons
@boxes = ("BUTTON1", "BUTTON2", "BUTTON3", "BUTTON4", "BUTTON5", "BUTTON6", "BUTTON7", "BUTTON8", "BUTTON9", "BUTTON10", "BUTTON11", "BUTTON12", "BUTTON13", "BUTTON14", "BUTTON15", "BUTTON16");

# put the buttons onto the scrollable pane in the frame on the window (LOL)
DisplayCheckButtons( $pane, @boxes);

# wait until the user exits the app
MainLoop;

# exit the app
exit 0;

sub DisplayCheckButtons 
{
    my ( $parent, @names ) = @_;
    $Frame->destroy if $Frame;
    $Frame = $parent->Frame(    -width => 160, 
                    -height => 555, 
                    -background => "GREY")->place(-x=>15,-y=>15);

    $xpos = 5;
    $ypos = 5;

    foreach $box (@names)
    {
        $buttons->{$box} = $Frame->Button(-text => $box)->place(-x=>$xpos,-y=>$ypos);

        $ypos = $ypos + 40;

    }
}

sub create_framed_section
{
    # get the parameters
    my($label, $labelside, $posX, $posY, $width, $height, $fontColour, $backgroundColour) = @_;

    # create the item in the desired position with supplied information
    $frame = $MW->LabFrame( -label      => $label,
                -labelside  => $labelside,
                -width      => $width,
                -height     => $height,
                -foreground => $fontColour,
                -background => $backgroundColour,
                )->place(-x=>$posX,-y=>$posY);

    return $frame;
}

I hope that someone can point out the minor thing that I have missed from this and end my frustration.

Answer 1

A few observations first: Your code is not strict safe which makes debugging harder. You are also not calling pack on any of your widgets. You shouldn’t use an ampersand before the sub name when invoking subs unless you know its effects and want them — see perldoc perlsub for details.

The widths of the three panels add up to more than 800. The layout you want is not that clear.

Now, here is some code (stolen from PerlMongers) that creates a scrollable pane with a bunch of buttons:

#!/usr/bin/perl

use strict;
use warnings;

use Tk;
use Tk::Pane;

my $top = MainWindow->new;
$top->Label(-text => "Enter the scroll frame")->pack;

my $frame = $top->Scrolled(
    'Frame',
    -scrollbars => "e",
)->pack;

$frame->Button(-text => "BUTTON $_")->pack for ( 1 .. 16 );

MainLoop;