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

Hi esteem monks,

I wanna read content of file to text widget. It appends a new line every 3 sec. Below is my code: 
use strict;
use warnings;

use Tk;



my $mw = MainWindow->new();
my $st = $mw->Scrolled("Text",-scrollbars => "eo")->pack();
$st->repeat(3000,\&list);
MainLoop;

sub list {
my $fh;
open ($fh, "<D:\\perl_script\\sqlnet.log") or die "error!!$!\n";
while (<$fh>) {
    $st->insert("end", $_);
}
close ($fh);
}

[download]
But it doesn't work well. Every 3 sec, text widget showed a page, not a line, furthermore, the slider doesn't jump to the end of the text, so you have to drag it to see new added contents.

any suggestions?

I am trying to improve my English skills, if you see a mistake please feel free to reply or /msg me a correction

Replies are listed 'Best First'.
Re: insert in Text widget
by shmem (Chancellor) on May 25, 2007 at 08:10 UTC
    You are reading the entire file in that loop: 
    while (<$fh>) {
    $st->insert("end", $_);
}

    [download]

    You probably want 

    use strict;
use warnings;

use Tk;

my $fh;
open ($fh, "<D:\\perl_script\\sqlnet.log") or die "error!!$!\n";

my $mw = MainWindow->new();
my $st = $mw->Scrolled("Text",-scrollbars => "eo")->pack();
my $id = $st->repeat(3000,\&list);
MainLoop;
close ($fh);

sub list {
    if (eof($fh)) {
        $st->aftercancel($id);
        return;
    }
    my $line = <$fh>;
    $st->insert('end', $line);
    $st->see('end');
}

    [download]

    Roughly.

    --shmem 

    _($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}
[reply]
[d/l]
[select]
      Thank you!!! It works!

      I am trying to improve my English skills, if you see a mistake please feel free to reply or /msg me a correction
[reply]
Re: insert in Text widget
by Khen1950fx (Canon) on May 25, 2007 at 21:53 UTC
    shmem's code is great++. I took a different tack, cleaned your code up a little, and came up with this:

    #!/usr/bin/perl

use strict;
use warnings;

use Tk;
use IO::File;

my $mw = MainWindow->new();
my $st = $mw->Scrolled( 'Text', -scrollbars => 'eo' )->pack();
$st->repeat( 3000, \&list );
MainLoop;

sub list {
    my $fh = IO::File->new();
    open $fh, q{<}, '/usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-
+multi/Tk/Text.pm';

    while (<$fh>) {
        $st->insert( 'end', "line $_\n" );
        return;
        
    }
}   
1;

    [download]

    Update: Fixed. It should work now. Sorry for the delay. The main reason that I did it this way is that I used Perl::Critic, and it recommended IO::File. Also, it recommended a 3-arg open, which seems to work a little better. There's an online Perl::Critic at http://perlcritic.com/

[reply]
[d/l]
      I've try your code, but it seems not work. Could you comment your key changes?

      I am trying to improve my English skills, if you see a mistake please feel free to reply or /msg me a correction
[reply]

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