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Re: Array of TK::Checkbuttons not acting appropriately

by mikasue (Friar)
on Oct 02, 2006 at 12:33 UTC ( #575864=note: print w/ replies, xml ) Need Help??


in reply to Array of TK::Checkbuttons not acting appropriately

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


Comment on Re: Array of TK::Checkbuttons not acting appropriately
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Re^2: Array of TK::Checkbuttons not acting appropriately
by davidrw (Prior) on Oct 02, 2006 at 13:19 UTC
    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 }
      THANK YOU davidrw!!!!
      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

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