Tk pop-up if condition is met

IB2017 has asked for the wisdom of the Perl Monks concerning the following question:

Is it possible to allow a popup in a text widget only if a condition is met, i.e. if a text has been selected? This is the code I have so far, which creates a popup, however, it checks if something has been selected only agter its creation.

use strict;
use warnings;
use Tk;
use Tk::Text;
my $mw = tkinit();
my $text = $mw->Text()->pack();
$text->insert('end',"This is my first line\n");
$text->insert('end',"This is my second line\n");

PupupTextWidget($mw, $text);
$mw->MainLoop();

sub PupupTextWidget{
  my ($mw, $obj) = @_;
  my $messagePopupSave;
  if ($^O eq 'MSWin32'){
    $messagePopupSave="Do something (ctrl+s)";
  }else{
    $messagePopupSave="Do something (cmd+s)";
  }
  my $menu = $mw->Menu(-tearoff=>0, -menuitems=>[
    [command=>$messagePopupSave, -command=>[sub {
        my $UserInput=$obj->getSelected;
        print $UserInput;
        }, $obj,]],
    [qw/command Copy/, -command=>['clipboardCopy', $obj,]],
    ]);

    $obj->menu($menu);

    return $obj;
}
[download]

Comment on Tk pop-up if condition is met Download Code

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Re: Tk pop-up if condition is met by jcb (Parson) on Aug 05, 2020 at 22:27 UTC
You probably want to configure the `-postcommand` on the `Menu` object; it is a callback invoked just before the menu appears and can modify the menu contents.	[reply] [d/l] [select]
Re^2: Tk pop-up if condition is met by IB2017 (Pilgrim) on Aug 06, 2020 at 11:45 UTC
Thank you. But how? I am trying several things with no success. For example `my $menu = $mw->Menu(-tearoff=>0, -postcommand => sub { return if $o +bj->getSelected eq "" }, -menuitems=>[ [command=>$messagePopupSave, -command=>[sub { my $UserInput=$obj->getSelected; print $UserInput; }, $obj,]], [qw/command Copy/, -command=>['clipboardCopy', $obj,]], ]);` [download]	[reply] [d/l]
Re^3: Tk pop-up if condition is met by jcb (Parson) on Aug 07, 2020 at 01:53 UTC
In the case where I needed this, I was attaching a submenu for suggestions while adding live spelling check to a Tk::Text widget. The code is basically a first draft of the concept as part of one of my personal "toy" projects. Here are some pieces: `my $main_text_field = $top->Text(-width => 132, height => 24, -setgrid => 1, -wrap => 'word'); my $main_text_field_spelling_menu = $main_text_field->menu->Menu(-tear +off => 0); $main_text_field_spelling_menu->configure (-postcommand => [\&post_suggestion_menu, $main_text_field, $main_text_field_spelling_menu]) +; $main_text_field->menu->insert ('View', cascade => -label => 'Respell...', -underline => 0, -menu => $main_text_field_spelling_menu);` [download] `sub post_suggestion_menu { my $widget = shift; my $menu = shift; my @wordpos; $menu->delete(0, 'end'); # extract word boundaries where user requested menu into @wordpos if (exists $spelling_suggestions{$word}) { $menu->add(command => -label => $_, -command => [\&replace_word, $widget, @wordpos, $_]) foreach @{$spelling_suggestions{$word}}; } else { $menu->add(command => -label => 'No suggestions.', -state => 'disa +bled'); } }` [download] The `-postcommand` callback is able to edit the menu before it is displayed, although in my use, I wanted a fully dynamic menu that is rebuilt every time the user (me) asks for it. Note that the menu will be displayed (as far as I know) after `-postcommand` returns. If you want to prevent displaying the menu at all, you would need to replace the binding that posts the menu.	[reply] [d/l] [select]
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