#!/usr/bin/perl -w


use Gtk;
use strict;

set_locale Gtk;
init Gtk;

my $false = 0;
my $true = 1;

my $window = new Gtk::Window( "toplevel" );
my $button = new Gtk::Button( "Button created with label" );
my $label;
my $id;
my $numclicked = 0;

# callback registration
$window->signal_connect( "delete_event", \&CloseWindowEvent );
$button->signal_connect( "clicked", \&ClickedButtonEvent );

# button attributes
$button->show();

# window attributes
$window->border_width( 15 );
$window->add( $button );
$window->show();

# Gtk event loop
main Gtk;

exit( 0 );



### Subroutines

# callback called when the button is clicked
sub ClickedButtonEvent
  {
    if ( $numclicked == 0 )
      {
	$button->child->set( "Changed Button Label" );
	$numclicked++;
      }
    elsif ( $numclicked == 1 )
      {
	$window->remove( $button );

	$button = new Gtk::Button();
	$label = new Gtk::Label( "Label added to a button" );
	$button->add( $label );
	$label->show();
	$button->show();
	$window->add( $button );
	$id = $button->signal_connect( "clicked", \&ClickedButtonEvent );
	$numclicked++;
      }
    elsif ( $numclicked == 2 )
      {
	$label->set( "Now Click to Close Window" );
	$numclicked++;
      }
    else
      {
	Gtk->exit( 0 );
      }
  }

# callback called when the window is asked to close
sub CloseWindowEvent
  {
    # If you return a false value in the "delete_event" signal
    # handler, GTK will emit the "delete_event" signal.
    # Returning a true value means you don't want the window to
    # be destroyed.
$window->window->move( 100, 100 );
    return $true;
  }


# END EXAMPLE PROGRAM