button disappears on resize? how to prevend

[ruud144]

hello group,

I need a short explanation about the behaviour of my script. It has
two listboxes next to each other and to buttons beneath it. The
listboxes should get a scrollbar when necessary. When testing that (it
works indeed), I saw that the listboxes only shrink and get a
scrollbar after the buttons were disappeared from the window.

I made a simple form of the script (one listbox and one button) to
show the behaviour.
My questions: what can I do about it, and more important: who can
explain what is going on. I have the Perl/Tk book; a pointer to the
right paragraph is welcome too.

thanks in advance, Ruud


use Tk::widgets qw (Listbox Button);
#!/usr/bin/perl
use strict;
use Carp;

use Tk::widgets qw (Listbox Button);

my $top = MainWindow->new();
my $button = $top->Button (-text => 'ok', -command => sub {exit
(0)});
my $listframe = $top->Frame ( -borderwidth => '2', -relief =>
'raised');
$listframe->pack(-expand => '1', -fill => 'both', -side =>
'top',);

my $lb = $listframe->Scrolled ('Listbox', -scrollbars => 'ow',
-selectmode => 'extended',
-label => 'test',
-takefocus => 1);
foreach (1..13) { $lb->insert ('end', "entry$_"); }
$lb->pack ( -side => "left", -fill => "both", -expand =>
'yes');


$button->pack ( -side => "bottom", -fill => "x", -expand =>
'1');

Tk::MainLoop();

[ruud144]

On Mar 14, 12:10 pm, ruud144 <r.grosm...@gmail.com> wrote:
> My questions: what can I do about it, and more important: who can
> explain what is going on. I have the Perl/Tk book; a pointer to the
> right  paragraph is welcome too.

Maybe it is not clear from the question, but I want the buttons to
stay in the window as long as possible. I want the list to be resized
rather than the button be pushed out of the window.

thanks, Ruud

[ruud144]

I found out it has to do with the packing order. In order to get the
behaviour I want, I have to pack the button before the frame with the
list in it is packed.

Ruud

[Horst-W. Radners]

ruud144 schrieb am 14.03.2013 14:31:> On Mar 14, 12:16 pm, ruud144

You are right, the packing order determines which widget disappears first.
But please note, that for the initial size of the whole window and a
clean behaviour on resizing (reduce and enlarge!), you should use
appropriate
combinations of the -side, -anchor, -fill and -expand options.
Moreover esp. listboxes have a -height option for the initial nb of lines.

#!/usr/bin/perl
use warnings;
use strict;

use Tk::widgets qw(Listbox Button);

my $top = MainWindow->new();

my $button = $top->Button(
-text => 'ok',
-command => sub {

exit(0);
})->pack(
-side => 'bottom',
-anchor => 's',
-fill => 'x',
-expand => '0' );

my $listframe = $top->Frame(
-borderwidth => '2',

-relief => 'raised',
)->pack(

-expand => '1',
-fill => 'both',
-side => 'top', );

my $lb = $listframe->Scrolled(
'Listbox',
-scrollbars => 'ow',
-selectmode => 'extended',
-label => 'test',

-takefocus => 1,
-height => 8,
)->pack(
-side => 'top',
-anchor => 'nw',
-fill => 'both',
-expand => '1' );
foreach ( 1 .. 13 ) { $lb->insert( 'end', "entry$_" ); }

Tk::MainLoop();

HTH, Horst
--
<remove S P A M 2x from my email address to get the real one>