I suspect this is a lack of understanding the underlying issue, but my google-fu is failing me.

I am in the process of writing a Tkx based program. At one point in this program I have to iterate through a list of files to do stuff with them. I want to provide the user visual feedback about how far along the list I am when I am iterating through the files.

The thing is that when I attempt to update my progress bar inside the iteration loop, the gui doesn't change.

I suspect the problem is a threading issue, where I'm not setting up my UI in a separate thread or something to that effect. Thing is that, if that is the problem, I can't find any documentation or howto for dummies to do it.

This is not complete code, but I think it's enough to get the idea of what I'm doing across.

use strict;
use XML::Twig;
use Tkx;
use Net::FTP;
use Thread;

# needed for frames and grids to work.
Tkx::package_require("tile");

# main window and properties
my $main_window = Tkx::widget->new(".");

my $grid = $main_window->new_ttk__frame( 
    # left going clockwise
    -padding => "1 1 1 1",
    -borderwidth => 5,
    );
$grid->g_grid(
    -column => 0,
    -row => 0, 
    -sticky => "nsew",
    );
    
$main_window->g_grid_columnconfigure(
    0,
    -weight => 1,
    );
$main_window->g_grid_rowconfigure(
    0,
    -weight => 1,
    );

&init();
Tkx::MainLoop();
sub init {
# Progress bar...
    my $progress = 0;
    my $overall_progress_bar = $grid->new_ttk__progressbar(
                -orient => "horizontal",
                -mode => "determinate",
                -length => "200",
                -maximum => $file_count,
                -value => $progress,
                );
# buttons...
    my $publish = $grid->new_button(
        -text => "Publish",
        -command => sub {
            # now for heavy lifting...
            # get a list of files to be FTPed.
            my @ftp_list = &get_ftp_list($chosen_dir);
            
            # get a count of how many files I'm FTPing.
            my $file_count = scalar(@ftp_list);
            
            # get the media ID of the capture
            my $media_id = &check_media_id($chosen_dir);
            
            $overall_progress_bar->configure(-maximum => $file_count);
            # FTP the files, and count the number of successes. 
foreach my $i (@ftp_list) {
                $progress++; 
                
                my $result = &ftp_file($i, $media_id, @profile_info);
                
                if ($result == 200) { 
                    $progress++; 
                    }
                }
            
            },
        );  
    # layout section    
    $choose_dir_label->g_grid(-column => 0, -row => 0, -columnspan => 
+2);
    $choose_dir->g_grid(-column => 2, -row => 0, -columnspan => 2);
    
    $chosen_dir_label->g_grid(-column => 0, -row => 1, -columnspan => 
+4);
    
    $profile_list_label->g_grid(-column => 0, -row => 2);
    $profile_list->g_grid(-column => 1, -row => 2, -columnspan => 2);
    
    $profile_info_label->g_grid(-column => 0, -row => 3, -columnspan =
+> 4);
    
    $publish->g_grid(-column =>0, -row => 4);
    $modify_settings->g_grid(-column => 1, -row => 4);
    $reset->g_grid(-column => 2, -row => 4);
    $exit->g_grid(-column => 3, -row => 4);
    
    $overall_progress_bar->g_grid(-column => 0, -row => 5, -columnspan
+ => 4);
    
    &layout($grid);        
    }

sub layout {
    # Grabs a list of the current elements on the grid and adds 2px pa
+dding
    # on every side of each element.
    foreach (Tkx::SplitList($_[0]->g_winfo_children)) {
        Tkx::grid_configure($_, -padx => 2, -pady => 2);
        }
    }
[download]