perl tk how to clear contents of text widget

john.tm has asked for the wisdom of the Perl Monks concerning the following question:

I have a perl tk gui with a Help_Guide command button and a text widget, which is filled from a txt file, i am trying to add a close_help button that will clear the contents of the text widget but get this error

Tk::Error: Not a CODE reference at C:/Perl/site/lib/Tk.pm line 251.
 Tk callback for .frame.frame.button3
 Tk::__ANON__ at C:/Perl/site/lib/Tk.pm line 251
 Tk::Button::butUp at C:/Perl/site/lib/Tk/Button.pm line 175
 <ButtonRelease-1>
 (command bound to event)
[download]

This my updated code which unfortunately still does not clear the text loaded from the help button.

use warnings;
use strict;
use Tk;
use Tk::Text ;
use POSIX 'strftime';
my $DATE = strftime("Run Failures.pl for %dth %b %Y" , localtime());
my $mw = MainWindow->new;
my $filename = "c:\\Temp\\perl.txt";

$mw->geometry("720x500");
$mw->title("   backupadmin  ");

my $main_frame = $mw->Frame()->pack(-side => 'top', -fill => 'x');

my $left_frame = $main_frame->Frame(-background => "snow2")->pack(-sid
+e => 'left', -fill => 'y');
my $right_frame = $main_frame->Scrolled("Text", -scrollbars => 'se',-b
+ackground => "black",-foreground => "yellow",-height => '44')->pack(-
+expand => 1, -fill => 'both');


my $failures_button = $left_frame->Button(-text => "  $DATE ",
                                -command => \&runscript)->pack;
my $Close_button = $left_frame->Button(-text => '                     
+  Close                       ',
-command => $mw => 'destroy')->pack;    
my $Help_button = $left_frame->Button(-text => "                  Help
+ Guide                   ",
                                -command => \&load_file)->pack(-side =
+> "bottom");


    

my $Close_help = $left_frame->Button(-text => ' Close Help ',
          -command => \&clear_file )->pack(-side => "bottom");

          

MainLoop;
sub runscript {
  system("daily_failures.pl");
# or if it takes some time to run the script
  #system("daily_failures.pl &"); # runs in the background
}

sub load_file {
  open (FH, "$filename");
  while (<FH>) { $right_frame->insert("end", $_); }
  close (FH);
}
sub clear_file {
    $right_frame->delete('1.0','end');
    $right_frame->packForget;
}
[download]

Comment on perl tk how to clear contents of text widget Select or Download Code

Replies are listed 'Best First'.
Re: perl tk how to clear contents of text widget by zentara (Cardinal) on Jun 28, 2014 at 17:40 UTC
The command to delete all text in a Tk::Text widget is `$text->delete("1.0", 'end');` [download] your command `-command => [$right_frame => \&clear_file])->pack(-side => "bottom")` [download] makes no sense. A Scrolled Text widget dosn't know what => means. Try this `my $Close_help = $left_frame->Button(-text => ' Close Help ', -command => \&clear_file )->pack(-side => "bottom"); sub clear_file { $right_frame->delete('1.0','end'); $right_frame->packForget; }` [download] I'm not really a human, but I play one on earth. Old Perl Programmer Haiku ................... flash japh	[reply] [d/l] [select]
Re^2: perl tk how to clear contents of text widget by john.tm (Scribe) on Jun 29, 2014 at 13:59 UTC
This still does not clear the text from the text widget.	[reply]
Re^3: perl tk how to clear contents of text widget by zentara (Cardinal) on Jun 30, 2014 at 09:27 UTC
It still dosn't clear You seem to like to use the array form for the -command. The code I showed you does NOT have the brackets. `-command => [$right_frame => \&clear_file]) #notice the difference -command => \&clear_file )` [download] Don't use the bracketed command form unless you know what you are doing with it. It is used if you want to pass arguments to a subroutine, which you don't need in this case. I'm not really a human, but I play one on earth. Old Perl Programmer Haiku ................... flash japh	[reply] [d/l]
Re^3: perl tk how to clear contents of text widget by Anonymous Monk on Jun 29, 2014 at 20:32 UTC
Can you prove it? Can you copy/paste your new program?	[reply]
Re^4: perl tk how to clear contents of text widget by john.tm (Scribe) on Jun 30, 2014 at 12:55 UTC
Re: perl tk how to clear contents of text widget by Anonymous Monk on Jun 28, 2014 at 19:29 UTC
... Tk::Error: Not a CODE reference ... You wrote `-command => [$right_frame => \&clear_file]` but $right_frame is not \&clear_file, you switched the order for some reason	[reply] [d/l]