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

Hey guys, I somehow screwed up this code. When it runs, it compiles fine, but then it just opens a blank command prompt window. Tk is installed properly, and I can get a basic hello world program running perfectly. Pretty much everything inside sub push_button is from an old program, and I know it works fine. The arrays normally have much more stuff in them.

#!/usr/bin/perl
use strict;
use warnings;
use diagnostics;
use Tk;
srand;


my $timelimits = 1;
my @numbers = (1..10);
my @building = ("Building");
my @adverb = ("Adverb");
my @verb = ("Verb");

my $mw = new MainWindow;
my $title = $mw -> Label(-text=>"Starcraft Strategy Generator") -> gri
+d();
my $howmany = $mw -> Label(-text=>"How many strategies?") -> grid();
my $ent = $mw -> Entry() -> grid();
my $button = $mw -> Button(-text=>"Generate Strategies", -command => \
+&push_button) -> grid();
my $checkminutes = $mw -> Checkbutton(-text=>"Use time limits?", -vari
+able=>\$timelimits) -> grid();
$checkminutes -> deselect();
my $output = $mw -> Text(-width=>500, -height=> 240) -> pack();

MainLoop;

sub push_button {

my $builds = $ent -> get();

while(0<$builds) {
if($timelimits == 1) {
my $numbersrand = rand @numbers;
my $buildingrand = rand @building;
my $adverbrand = rand @adverb;
my $verbrand = rand @verb;

my $numbersout = $numbers[$numbersrand];
my $minuteout = "Minute";
my $buildingout = $building[$buildingrand];
my $adverbout = $adverb[$adverbrand];
my $verbout = $verb[$verbrand];

$output -> insert('end',"$numbersout $minuteout $buildingout $adverbou
+t $verbout\n");
$builds --;
}
else
{

my $numbersrand = rand @numbers;
my $buildingrand = rand @building;
my $adverbrand = rand @adverb;
my $verbrand = rand @verb;

my $numbersout = $numbers[$numbersrand];
my $buildingout = $building[$buildingrand];
my $adverbout = $adverb[$adverbrand];
my $verbout = $verb[$verbrand];

$output -> insert("$numbersout $buildingout $adverbout $verbout\n");
$builds --;
}
}
$output -> insert("Done\n");
}

[download]

Replies are listed 'Best First'.
Re: Tk problem
by kcott (Archbishop) on Sep 01, 2011 at 04:37 UTC

    Your problem is mixing the geometry managers Tk::grid and Tk::pack in the one frame (in this case, the special frame Tk::MainWindow).

    If you want to mix them, put the first five widgets in their own Tk::Frame.

    I changed the lone pack() to grid() and your reported problem was resolved, i.e. a window now appears. 

    my $output = $mw -> Text(-width=>500, -height=> 240) -> grid();

    [download]

    I didn't check any functionality beyond this.

    -- Ken

[reply]
[d/l]
[select]

      Thanks, I had no idea you had to stick to one, I thought you could just mix and match pack and grid.

[reply]
Re: Tk problem
by Khen1950fx (Canon) on Sep 01, 2011 at 08:15 UTC
    From what I can see, you're a little confused about the difference between pack and grid. In your snippet, you were using the pack manager. I wish that we could just switch managers by switching words, but we can't just yet.

    Here's how it works with pack. I pared back a little. The push_button wasn't much help, so I left the callbacks out. 

    
#!/usr/bin/perl

use strict;
use warnings;
use Tk;

my $mw = MainWindow->new;
$mw->Label( -text => 'Starcraft Strategy Generator' )->pack;
$mw->Button(
   -text => 'Generate Strategies'
   )->pack;
$mw->Entry->pack;
$mw->Checkbutton(
   -text => 'Use time limits?'
   )->pack;
$mw->Entry->pack;
$mw->Text(
   -width => 20, 
   -height=> 10
   )->pack;

MainLoop;

    [download]
    If you can post some more specific info, I can help you set it up using the grid manager.
[reply]
[d/l]

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