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

Howdy,


I'm wondering about the following in my code:

1. My code barfs shortly after clicking on the "About..." Is it possible to make the Toplevel $tl modal (i.e. hold focus until the close button is depressed)? If so, how?

2. I've had to comment out strict because I'm not sure exactly how to pass the $mw from main to the sub do_toplevel. Can I safely use strict in a Tk program? If so, what syntax could I use to send $mw along?

#!perl -w
=pod
IP & Hostname GUI Program
v .3
slojuggler
=cut

#use strict;
use Socket;
use Sys::HostIP;

#For hostname
use Sys::Hostname;


my $ipaddr = hostip;
print "Mine: $ipaddr \n";

my $hostnm = hostname();
print "Host $hostnm \n";

use Tk;

my $mw = MainWindow->new;
$mw->title("Your IP Info");
$mw->Label(-text=>"IP Address -> $ipaddr")
                 ->pack(-fill => 'x',
                           -side=>"top",
                            -ipadx=>20);
$mw->Label(-text=>"Hostname -> $hostnm")
                 ->pack(-fill => 'x',
                           -side=>"top");
$mw->Button(-text=>"Done!", -command=> sub { exit } ) -> pack (-side=>
+"bottom");

#Somehow pass the $mw to the do_toplevel routine, to keep in step with
+ use strict
#$mw->Button(-text=>"About...", -command=> \&do_toplevel + $mw arg som
+ehow??? } ) -> pack (-side=>"bottom");
$mw->Button(-text=>"About...",
                   -command => \&do_toplevel ) -> pack (-side=>"bottom
+"); 
MainLoop();

sub do_toplevel {
    #Somehow pick up the $mw by using something like the following?
    #my $tl = shift or whatever it takes to bring in the passed in var
+;         ???
    my $tl = $mw->Toplevel();
    $tl->title("Aboutl");
    $tl->Button(-text => "Close",
                     - command => sub {$tl->destroy})->pack;
    $tl->waitWindow();
}

[download]

Thanks... --slojuggler

Replies are listed 'Best First'.
Re: Modal Tk Toplevel/Passing a MainWindow
by kschwab (Vicar) on Sep 08, 2001 at 18:00 UTC
    1. You could:
    • Roll your own focus/grab management with $widget->grab and $widget->focus. See grab and focus. You may also want to see the "busy" method mentioned in Tk:Widget.
    • Use a prebuilt widget like Tk::Dialog (can't find the docs) or Tk::DialogBox. These automatically take focus, do a grab, and release once the modal dialog is answered.

    2. Have a look at Tk::Callbacks. In your case,  -command => [\&do_toplevel,$mw] ) should work. ( You could then use shift() as you mentioned, to get at $mw )

[reply]
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Re: Modal Tk Toplevel/Passing a MainWindow
by chromatic (Archbishop) on Sep 08, 2001 at 22:42 UTC
    Another approach is to use an anonymous function. Hey, it's even a closure! 
    $mw->Button(
    -text=>"About...", 
    -command=> sub { do_toplevel($mw) } }
)-> pack (-side=>"bottom");

    [download]
    It's the same sort of thing you do later on for the Close button in do_toplevel(). :)
[reply]
[d/l]
[select]
      chromatic/kschwab, Thanks for your help! I played with DialogBox and it does the job. Both the anonymous method as well as the [] methods work well for passing. Is one method preferred to the other, or should I go by the TMTWOTDI way?

      Curious, is there a module or a Tk Option I can use to center the initial MainWindow ($mw). When I run the current code, the $mw pops up in a fairly random place, yet the DialogBox shows up dead center. This gets a little visually startling.

      The code now looks like this: 

      #!perl -w
=pod
IP & Hostname GUI Program
v .3
slojuggler
=cut

#use strict;
use Socket;
use Sys::HostIP;

#For hostname
use Sys::Hostname;

print "@INC" . "\n";

my $ipaddr = hostip;
print "Mine: $ipaddr \n";

my $hostnm = hostname();
print "Host $hostnm \n";

use Tk;
use Tk::DialogBox;

my $mw = MainWindow->new;
$mw->title("Your IP Info");
$mw->Label(-text=>"IP Address -> $ipaddr")
                 ->pack(-fill => 'x',
                           -side=>"top",
                            -ipadx=>20);
$mw->Label(-text=>"Hostname -> $hostnm")
                 ->pack(-fill => 'x',
                           -side=>"top");
$mw->Button(-text=>"Done!", -command=> sub { exit } ) -> pack (-side=>
+"bottom");

#Somehow pass the $mw to the do_toplevel routine, to keep in step with
+ use strict
#$mw->Button(-text=>"About...", -command=> sub { \&do_toplevel ????? }
+ ) -> pack (-side=>"bottom");
$mw->Button(-text=>"About...",
                   -command => sub { do_toplevel($mw) }) -> pack (-sid
+e=>"bottom"); 
MainLoop();

exit();

sub do_toplevel {
    my $mainwindow = shift;
    my $dialog = $mainwindow->DialogBox(-title => "About...", -buttons
+ => ["OK"]);
    my $label = $dialog->add('Label', -text=>"V1.2")->pack(-fill=> 'x'
+,  -side=>"top");
    $dialog->Show;
=pod
    my $tl = $mainwindow->Toplevel();
   $tl->title("About...");
    $tl->Button(-text => "Close",
                     - command => sub {$tl->destroy})->pack;
    $tl->waitWindow();
=cut
    
}

      [download]
[reply]
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