[wxperl-users] Major woes - trees in ScrolledWindow

[Nick J. <sk...@er...>]

I'm using wxPerl on Win32, and I'm struggling. I've looked at all the
introductory tutorials I can find--and while I can now easily create a
frame and add menus to it, I'm having trouble doing anything else.



 Anyway, I am creating a music organiser application. The general design
is that there will be variable-width "split" at the left hand side of the
window which will display the user's music collection as a tree structure.
At the minute, my program creates a window, menus and is split into two
using Wx::SplitterWindow. Each of the split canvases is a
Wx::ScrolledWindow.

 Generally, I don't really understand how wxPerl operates. What I
understand is that you must, at the very least, extend Wx::Frame and
Wx::App and provide an OnInit method for Wx::App. That's fine, I can
understand that, and I can understand wx's event model. I can understand
creating menus, and that seems relatively straightforward.

 What I don't understand is how to create other controls inside the
different canvases. When I look at the documentation for the C++ version
of wx, I see that when I create a control, I need to specify a parent. As
far as I know, this can be any class derived from Wx::Window. However,
some of the example wxPerl programs (from which I've learnt most of what I
know about wx!) seem to suggest that objects derived from Wx::Window have
a method called "add" or similar that can be used to add controls to
windows or canvases. However, Wx::ScrolledWindow doesn't seem to support
this.

 In the code below, when I've created a tree, I've specified $lcanvas, a
reference to the left hand canvas, as the parent. If I change this to
$self (the window or frame?), the window isn't split properly and only a
small rectangular region is displayed. So, my main questions are:
- How can I add a tree to the left-hand part/canvas of the window?
- How can I generally add controls to frames?
- How can I create multiple frames for my application? How can I load and unload them?

I'm also having problems with toolbars (not included in code below). I can
create a toolbar but no buttons appear in it (I have added one button and
I have called the realise method on the toolbar).

Here's the problematic code:

#!/usr/bin/perl

use strict;
use Wx;

package MyCanvas;

use strict;
use vars qw(@ISA);

@ISA = qw(Wx::ScrolledWindow);

sub new {
  my( $class ) = shift;
  my( $this ) = $class->SUPER::new( @_[0,1,2,3], 0, $_[4] );

  return $this;
}

package MusicOrganiserSplitterWindow;
use strict;
use vars qw(@ISA);

@ISA = qw(Wx::SplitterWindow);

use Wx qw(:splitterwindow wxDefaultPosition wxDefaultSize);
use Wx::Event qw(EVT_SPLITTER_SASH_POS_CHANGED);

sub new {
  my( $class ) = shift;
  my( $this ) = $class->SUPER::new( @_, wxDefaultPosition, wxDefaultSize,
                                    wxSP_3D|wxSP_LIVE_UPDATE );

  $this->{FRAME} = $_[0];

  return $this;
}

# Extend Wx's "Frame" class to create the main window.
package MusicOrganiserFrame;

use base qw(Wx::Frame);
use Wx qw(wxOK wxICON_INFORMATION wxDefaultPosition wxDefaultSize);
use Wx::Event qw(EVT_MENU);

sub new {
  my $class = shift;
  my $self = $class->SUPER::new(@_);  # Call superclass' constructor

  # Assign ID values
  my ($ID_MENU_FILE_REPORT, $ID_MENU_FILE_STATISTICS, $ID_MENU_EDIT_ADD,
      $ID_MENU_EDIT_DELETE, $ID_MENU_TOOLS_SETUP, $ID_MENU_HELP_CONTENTS,
      $ID_MENU_HELP_ABOUT, $ID_MENU_FILE_EXIT) = (1 .. 100);

  # Create menu objects
  my $file_menu = Wx::Menu->new();
  my $tools_menu = Wx::Menu->new();
  my $edit_menu = Wx::Menu->new();
  my $help_menu = Wx::Menu->new();

  # Create File menu
  $file_menu->Append($ID_MENU_FILE_REPORT, "\&Report\tCtrl+R",
    "Produce reports about your collection.");
  $file_menu->Append($ID_MENU_FILE_STATISTICS, "\&Statistics\tCtrl+S",
    "Display statistics for part or all of your collection.");
  $file_menu->AppendSeparator();
  $file_menu->Append($ID_MENU_FILE_EXIT, "E\&xit\tCtrl+Q");

  # Create Edit menu
  $edit_menu->Append($ID_MENU_EDIT_ADD, "\&Add volume",
    "Add a volume to your collection.");
  $edit_menu->Append($ID_MENU_EDIT_DELETE, "\&Delete volume",
    "Delete a volume from your collection.");

  # Create Tools menu
  $tools_menu->Append($ID_MENU_TOOLS_SETUP, "\&Setup",
    "Configure Music Organiser.");

  # Create Help menu
  $help_menu->Append($ID_MENU_HELP_CONTENTS, "\&Contents");
  $help_menu->AppendSeparator();
  $help_menu->Append($ID_MENU_HELP_ABOUT, "\&About");

  # Create the menu bar that stores all the above menus
  my $menubar = Wx::MenuBar->new();
  $menubar->Append($file_menu, '&File');
  $menubar->Append($edit_menu, '&Edit');
  $menubar->Append($tools_menu, '&Tools');
  $menubar->Append($help_menu, '&Help');
  $self->SetMenuBar($menubar);

  # Set up event handling for menu items.
  EVT_MENU($self, $ID_MENU_FILE_REPORT, \&OnMenu);

  # Set window icon
  $self->SetIcon(Wx::GetWxPerlIcon());

  # Create status bar and assign values to the various segments
  $self->CreateStatusBar(3);
  $self->SetStatusText("Welcome to Music Organiser!", 1);
  $self->SetStatusText(scalar(gmtime), 2);


  my ($splitter) = $self->{SPLITTER} =
    MusicOrganiserSplitterWindow->new($self, -1);
  my ($lcanvas) = $self->{LEFTCANVAS} = MyCanvas->new($splitter, -1,
                                                        [0,0], [400,400],
                                                        'Test1');

  my ($rcanvas) = $self->{RIGHTCANVAS} = MyCanvas->new($splitter, -1,
                                                         [0,0], [400,400],
                                                         'Test2');

  $self->{TREE} = MusicOrganiserTree->new($lcanvas, -1, wxDefaultPosition,
  wxDefaultSize, wxTR_HAS_BUTTONS);

  $self->{SPLITTER}->SetMinimumPaneSize(250);
  $splitter->Initialize($lcanvas);
  $self->{LEFTCANVAS}->Show( 1 );
  $self->{RIGHTCANVAS}->Show( 1 );
  $self->{SPLITTER}->SplitVertically( @{$self}{'LEFTCANVAS','RIGHTCANVAS'}
);

  $self->{SPLITTER}->SetSashPosition(250,1);
  return $self;
}

sub OnMenu {
  Wx::MessageBox("Menu item selected", "Menu selected",
              wxOK | wxICON_INFORMATION, $_[0]);
}

package MusicOrganiserTree;

use strict;

use base qw(Wx::TreeCtrl);

sub new {
  my $class = shift;
  my $this = $class->SUPER::new(@_);

  my $root = $this->AddRoot('Root', -1, -1,
Wx::TreeItemData->new('Data'));

  my $tree_item;

  $tree_item = $this->AppendItem($root, "Please work", -1, -1,
    Wx::TreeItemData->new("I really hope this works!"));
}

package MusicOrganiserApp;

use base qw(Wx::App);

sub OnInit {
  my $self = shift;
  my $frame = MusicOrganiserFrame->new(
    undef,                 # Parent window
    -1,                    # Window ID
    'Music Organiser',     # Window title
    [1, 1],                # X, Y position
    [600, 300]             # X, Y size
  );

  $self->SetTopWindow($frame);  # Set the top-level window.
  $frame->Show(1);              # Show the frame.
}

package main;

my $app = MusicOrganiserApp->new();
$app->MainLoop;


I would really appreciate any help on this.

Thanks in advance,

Nick