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

my $mw = MainWindow->new;   
my $top = $mw->Frame()->pack();
my $GoBtn = $top->Button(-text => 'Pop It!', -command => \&AddItem)->pack();
my $DoneBtn = $top->Button(-text => ' Exit ', -command => \&Cleanup)->pack();
my $progress = $top->ProgressBar(
        -width => 20,
        -length => 100,
        -anchor => 'w',
        -from => 0,
        -to => 9,
        -blocks => 1,
        -colors => [0, 'green']
)->pack();    
$mw->focus;  
MainLoop;    

sub Cleanup {
   $mw->destroy;
}

sub AddItem {
	$GoBtn->configure(-state => "disabled");
	for (0 .. 9) {
		sleep 1;
		$progress->value($_);
		$progress->update();
	}
	$GoBtn->configure(-state => "normal");
	$progress->value(0);
	$progress->update();
}