Re: Array of TK::Checkbuttons not acting appropriately

[mikasue]

Thanks for your help. I have been trying to figure this out all weekend and got a little frustrated.

Forgive me everyone.

Here is a little snippet that everyone can run to see my problem. The problem again is when I click 1 checkbutton they all get selected.

use strict;
use warnings;
use Tk;
use Tk::Table;


our $MW = MainWindow->new(%{$BPP::BPPDEFAULTS::MYDEFAULTS{MAINWINDOW}}
+); 
$MW->geometry('800x700+0+0');
my $tableframe = $MW->Frame(-background=>'white'
                )->pack(-side=>'top', 
                    -fill=>'both',
                           -pady=>20);
            
my $bill_table = $tableframe->Table(-rows=>2, 
                -columns=>3, 
                -background=>'pink', 
                -scrollbars=>'e'
                )->pack(-fill=>'both', 
                    -side=>'top', 
                    -anchor=>'s');
                
my @foo = qw/ Apple Oranges Pears/;
my $x = 1;
my $checkbox;
my $checkboxvalue = 0;
foreach my $f (@foo)
{
$checkbox = $bill_table->Checkbutton(-variable=>\$checkboxvalue);
$bill_table->put($x,0, $checkbox);
$bill_table->put($x,1, $f);

$bill_table->Button(-text=>'Submit',
        -command=>sub{print $f}
        )->pack;
$x++;
}#end foreach loop

MainLoop;

So to distinguish them I tried putting the -variable value in an array. This fixes the selection issue but then that -variable value is not being set when I click on the checkbutton. I get this error: Use of uninitialized value in numeric eq (==)

use strict;
use warnings;
use Tk;
use Tk::Table;


our $MW = MainWindow->new(%{$BPP::BPPDEFAULTS::MYDEFAULTS{MAINWINDOW}}
+); 
$MW->geometry('800x700+0+0');

    my $tableframe = $MW->Frame(-background=>'white'
                )->pack(-side=>'top', 
                    -fill=>'both',
                           -pady=>20);
            
    my $bill_table = $tableframe->Table(-rows=>2, 
                        -columns=>3, 
                        -background=>'pink', 
                        -scrollbars=>'e'
                        )->pack(-fill=>'both', 
                            -side=>'top', 
                            -anchor=>'s');
                
my @foo = qw/ Apple Oranges Pears/;
my $x = 1;
my $t=0;
my $checkbox;
my @checkboxvalue;
foreach my $f (@foo)
{
$checkbox = $bill_table->Checkbutton(-variable=>\$checkboxvalue[$t]);
$bill_table->put($x,0, $checkbox);
        $bill_table->put($x,1, $f);

        $bill_table->Button(-text=>'Submit',
                        -command=>sub{if ($checkboxvalue[$t] ==1){prin
+t $f}}
                        )->pack;

        $x++;
        $t++;
    }#end foreach loop

MainLoop;

I hope this makes my problem clearer.
================================================

I need a Checkbutton and a Submit button on each line becuase there will be distinct information I need to change on each line. When the Checkbutton is selected, the information in that line is editable and the Submit button submits those changes for that line only.

I also need a reference to the checkbutton in order to PUT it in the table.

$checkbox = $bill_table->Checkbutton(-variable=>\$checkboxvalue[$t]);
$bill_table->put($x,0, $checkbox);

Thanks again for all ya'll help

[davidrw]

The problem is with the closure (the anonymous sub{...}</> that -command is) and the scope of $t.  Put a <c>warn $t in the sub{} to see what it's doing -- you'll see that it's always 3 which is the value of t after the foreach my $f (@foo) ... Here are two different approaches to solving it:

Here, you can use a temp value to hold the current value of $t. Since $i is scoped inside the for loop, it is different for each closure that is made.

    my $i=$t;
        $bill_table->Button(-text=>'Submit',
                        -command=>sub{if ($checkboxvalue[$i] ==1){prin
+t $f}},
                        )->pack;

Alternatively, use the form of Tk::callback that lets you provide arguments to a sub. Here our anonymous sub takes two args -- a reference to a scalar which is the checkbox value, and a scalar which is the text of the checkbox.

        $bill_table->Button(-text=>'Submit',
                        -command=>[
                           sub{
                             my $valref = shift;
                             my $valname=shift;
                             if ($$valref ==1){print $valname}
                           },
                           \$checkboxvalue[$t],
                           $f,
                        ],
                        )->pack;

Now, there's the issue of your Use of uninitialized value in numeric eq (==) .. That is because the checkbox values are either 1 or undef, so when you check <thecheckboxvalue>==1 it'll do either 1==1 (ok) or undef==1 (warning).
To solve, simply do one of these (probably the first? not sure that being exactly 1 is important, as long as it's true:

  if( $foo ){ print $f }
  if( defined $foo ){ print $f }

  if( $foo && $foo==1){ print $f }
  if( defined $foo && $foo==1){ print $f }

[mikasue]

THANK YOU davidrw!!!!

[rcseege]

That is because the checkbox values are either 1 or undef

I'm a little puzzled. Checkbutton values are supposed to be 1 or 0, defaulting to 0, though I can't argue with what I'm seeing. Try selecting, then deselecting a Checkbutton using mikasue's last example. When you press the Submit button for that row now, you shouldn't see the "Use of unitialized..." message, because now the value is 0 instead of undef. I'm going to have to take another look at why my second and third examples didn't behave this way.

Having said that, I agree that your first condition:  if ($foo) { ... } is best for this.

Rob