GladeXML and "widget is not of type Gtk::Widget"

[Tom Jennings <tomj wps com>]

This may be one of those it-goes-away-in-the-morning type problems,
but I'm quite stumped.

I'm trying to puzzle out GladeXML so I can use it on a new project.
Iv'e taken the "CList" example from the Gtk Perl Tutorial and
making the *tiniest* incremental changes to create the widgets
from GladeXML.

The crux of the problem is this:

$window= (new window...)                                # creates window OK
$vbox= $app-> get_widget ('vbox');                      # no error here,
$window-> add( $vbox );                                 # FAILS

This error results:

widget is not of type Gtk::Widget at ./test line 39.

What fails is the "window-> add" method call.  If I change the
code to $vbox= new Gtk::VBox... it works. Which I thought gladexml
'get_widget' returned type Gtk::Widget?

The XML definition is:
<widget>
  <class>GtkVBox</class>
  <name>vbox</name>
</widget>

The actual source and XML follows. I de-heirarchicalized (sic)
the XML for testing.  I realize GladXML has no "CList" widget,
I'll do it with old List.

Thanks for any insight, and sorry for the long message.
tomj





HACKED DEMO -- see "# tomj FAILS"

#!/usr/bin/perl -w

use Gtk;
use strict;
use Gnome;
use Gtk::GladeXML;      # tomj


set_locale Gtk;
init Gtk;

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

my $window;
my $vbox;
my $hbox;
my $scrolled_window;
my $clist;
my $button_add;
my $button_clear;
my $button_hide_show;

my $titles_visible = $true;
my @titles = ( "Ingredients", "Amount" );




# Create the window
#$window = new Gtk::Window( "toplevel" );               # tomj
my $app= Gtk::GladeXML->new('test.glade', 'welcome');   # tomj
$window= $app-> get_widget ('welcome');                 # tomj
$window->set_usize( 300, 150 );
$window->signal_connect( "destroy", sub { Gtk->exit( 0 ); } );

#$vbox = new Gtk::VBox( $false, 5 );                    # tomj
$vbox= $app-> get_widget ('vbox');                      # tomj
$window->add( $vbox );                                  # tomj FAILS
$vbox->border_width( 5 );
$vbox->show();


# Create a scrolled window to pack the CList widget into
$scrolled_window = new Gtk::ScrolledWindow( undef, undef );

$vbox->pack_start( $scrolled_window, $true, $true, 0 );
$scrolled_window->set_policy( 'automatic', 'always' );
$scrolled_window->show();

# Create the CList. For this example we use 2 columns
$clist = new_with_titles Gtk::CList( @titles );
#$clist= $app-> get_widget ('repList');

# When a selection is made, we want to know about it. The callback
# used is selection_made, and its code can be found further down
$clist->signal_connect( "select_row", \&selection_made );

# It isn't necessary to shadow the border, but it looks nice :)
$clist->set_shadow_type( 'out' );

# What however is important, is that we set the column widths as
# they will never be right otherwise. Note that the columns are
# numbered from 0 and up (to 1 in this case).
$clist->set_column_width( 0, 150 );

# Add the CList widget to the vertical box and show it.
$scrolled_window->add( $clist );
$clist->show();

# Create the buttons and add them to the window.
$hbox = new Gtk::HBox( $false, 0 );
$vbox->pack_start( $hbox, $false, $true, 0 );
$hbox->show();

$button_add = new Gtk::Button( "Add List" );
$button_clear = new Gtk::Button( "Clear List" );
$button_hide_show = new Gtk::Button( "Hide/Show Titles" );

$hbox->pack_start( $button_add, $true, $true, 0 );
$hbox->pack_start( $button_clear, $true, $true, 0 );
$hbox->pack_start( $button_hide_show, $true, $true, 0 );

# Connect our callbacks to the three buttons
$button_add->signal_connect( "clicked", \&button_add_clicked, $clist );
$button_clear->signal_connect( "clicked", sub { $clist->clear(); } );
$button_hide_show->signal_connect( "clicked", \&button_hide_show_clicked, $clist );

$button_add->show();
$button_clear->show();
$button_hide_show->show();

$window->show();
main Gtk;
exit( 0 );



### Subroutines


# User clicked the "Add List" button.

sub button_add_clicked
{
   my ( $widget, $clist ) = @_;

   # Something silly to add to the list. 4 rows of 2 columns each.
   my @drink = ( [ Milk    => "3 Oz" ],
                 [ Water   => "6 l"  ],
                 [ Carrots => "2"    ],
                 [ Snakes  => "55"   ] );

    # Here we do the actual adding of the text. It's done once for each row.
    for my $i ( 0..3 )
    {
       $clist->append( @{$drink[ $i ]} );
    }

   # For those who may not have understood the above, here is a brief
   # explanation.  @drink is a list of references to anonymouse lists
   # (references are scalars holding a memory address, similar to
   # pointers).  This is used because Perl doesn't directly support
   # two-dimensional arrays.  Because of this, $drink[$i] is not a
   # list, but a reference to one, so we must dereference it by
   # enclosing it like this: @{ reference } ( we use @ because it is a
   # reference to a list.  For further information on references, see
   # the perlref(1) man page, or chapter 4 of _Programming Perl_.

   return;
}


# The user clicked the "Hide/Show titles" button.

sub button_hide_show_clicked
{
   my ( $widget, $clist ) = @_;

   if ( $titles_visible )
   {
      # Hide the titles and set the flag to 1
      $clist->column_titles_hide();
      $titles_visible++;
   }
   else
   {
      # Show the titles and reset flag to 0
      $clist->column_titles_show();
      $titles_visible--;
   }
}


# If we come here, then the user has selected a row in the list.

sub selection_made
{
   my ( $clist, $row, $column, $event, @data ) = @_;

   my $text;

   # Get the text that is stored in the selected row and column
   # which was clicked in. We will receive it as a pointer in the
   # argument text.
   $text = $clist->get_text( $row, $column );

   # Just prints some information about the selected row
   print( "You selected row $row.  More specifically, you clicked in\n" );
   print( "column $column, and the text in this cell is:\n" );
   print( "    $text\n\n" );

   return;
}






<?xml version="1.0"?>
<GTK-Interface>

<widget>
  <class>GtkWindow</class>
  <name>welcome</name>
  <title>welcome</title>
</widget>


<widget>
  <class>GtkVBox</class>
  <name>vbox</name>
</widget>

<widget>
  <class>GtkScrolledWindow</class>
  <name>listWindow</name>
  <hscrollbar_policy>GTK_POLICY_AUTOMATIC</hscrollbar_policy>
  <vscrollbar_policy>GTK_POLICY_AUTOMATIC</vscrollbar_policy>
  <hupdate_policy>GTK_UPDATE_CONTINUOUS</hupdate_policy>
  <vupdate_policy>GTK_UPDATE_CONTINUOUS</vupdate_policy>
</widget>

<widget>
  <class>CList</class>
  <name>repList</name>
  <border_width>5</border_width>
  <handle_size>10</handle_size>
  <gutter_size>6</gutter_size>
  <position>171</position>
</widget>


</GTK-Interface>