#!/usr/bin/perl

use strict;
use warnings;
use Tk;
use Tk::ProgressBar;

my $mw = tkinit;
my $btn = $mw->Button(-text => 'start...', -command => \&readdr)->pack();

MainLoop;

sub readdr{
  my $top = $mw->Toplevel();
  my $progress = $top->ProgressBar(-from => 0, 
                                   -to => 100, 
                                   -colors => [0,'green'],
                                   -gap => 1)->pack();

  opendir(DIR,'.') or die $!;
  while(my $file = readdir(DIR)){
    my $values = $progress->value();
    $progress->value($values+2);
    sleep(1);
  }
  closedir(DIR);