Change the state of Tk::Button widget based on a variable?

coderama has asked for the wisdom of the Perl Monks concerning the following question:

Is it possible to change the state of a Tk::Button widget based on a variable? I don't see where this is possible out of the box, but my initial thought was to create a timer that evaluates the value of a variable and configures the button based on the value of the variable. Any better ideas? The example below changes the button's state to active when $number equals 1

use Tk;
my $number = 0;
my $mw = tkinit();
my $button = $mw->Button(-text => 'Button')->pack(-side => 'left');
my $label=$mw->Label(-textvariable=>\$number)->pack(-side=>'left');
my $timer = $mw->repeat(100, sub{
    $number = int(rand(5));
    if ( $number == 1 ){
        $button->configure(-state => 'normal');
    } else {
        $button->configure(-state => 'disabled');
    }
});
$mw->MainLoop();
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Re: Change the state of Tk::Button widget based on a variable? by zentara (Cardinal) on Sep 28, 2011 at 16:51 UTC
Use Tie::Watch #!/usr/bin/perl use warnings; use strict; use Tk; use Tie::Watch; my $mw = MainWindow->new; $mw->fontCreate('big', -weight=>'bold', -size=> 18 ); my $foo='neutrino'; my $watch = Tie::Watch->new(-variable => \$foo, -store => \&store_call +back); my $entry = $mw->Entry(-textvariable => \$foo, -bg => 'white', -font => 'big')->pack; $entry->icursor('end'); $entry->focus; my $testbutton; $testbutton = $mw->Button(-text => 'Foo Watcher', -state => 'disabled', -command => sub{ print "$foo\n"; $testbutton->configure(-state => 'disabled', -bg=>'white', -activebackground => 'white', ); }, -bg => 'white', -font => 'big', )->pack; my $quit = $mw->Button(-text => 'Quit', -command => sub { print "Final value=$foo.\n"; exit; })->pack; # a simple MainLoop; sub store_callback { print "In store_callback, self=$_[0], new_value=$_[1].\n"; $testbutton->configure( -state => 'normal', -bg => 'yellow', -activebackground => 'yellow', ); $_[0]->Store($_[1]); } [download] I'm not really a human, but I play one on earth. Old Perl Programmer Haiku ................... flash japh	[reply] [d/l]

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Re: Change the state of Tk::Button widget based on a variable?
by zentara (Cardinal) on Sep 28, 2011 at 16:51 UTC

#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tie::Watch;

my $mw = MainWindow->new;

$mw->fontCreate('big',
   -weight=>'bold',
   -size=> 18
   );


my $foo='neutrino';

my $watch = Tie::Watch->new(-variable => \$foo, -store => \&store_call
+back);

my $entry = $mw->Entry(-textvariable => \$foo,
                -bg => 'white',
                -font => 'big')->pack;
$entry->icursor('end');
$entry->focus;

my $testbutton;
$testbutton = $mw->Button(-text => 'Foo Watcher', 
              -state => 'disabled',   
              -command => sub{ print "$foo\n";
               $testbutton->configure(-state => 'disabled', 
               -bg=>'white',
               -activebackground => 'white',
               );     
              
                },
               -bg => 'white',
               -font => 'big',
            )->pack;

my $quit = $mw->Button(-text => 'Quit', -command => sub {
    print "Final value=$foo.\n";
    exit;
})->pack;


# a simple


MainLoop;

sub store_callback {
    print "In store_callback, self=$_[0], new_value=$_[1].\n";
    
    $testbutton->configure( -state => 'normal', 
    -bg => 'yellow',
    -activebackground => 'yellow',
     );

    $_[0]->Store($_[1]);
}
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I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

[reply]
[d/l]