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

I'm trying to get the hang of perl Tk. I thought an extreamly simple clock would be a good project. Getting the time is easy enough, as is displaying it. But what I want is a label that updates every second.

Anyway I went through the tk documentation, but it is very short on code examples, I tried to used the Tk::After method, but I didn't do anything new, I just get a window with a static time. I couldn't find anything I could use when I did a super search. Can someone point me in the right direction?

My project so far: 

#!/usr/bin/perl
    use Tk;
    $top = new MainWindow;
    $id = Tk::After->new($top->Label(-text =>&gettime)->pack,1000,'rep
+eat',\&gettime);
    MainLoop;

    
sub gettime{
    ($sec,$min,$hour,$day,$month,$year,$wday,$yday,$isDST) = localtime
+();
    @mname=("January","February","March","April","May","June",
            "July","August","September","October","November","December
+");
    @weekday=("Sunday","Monday","Tuesday","Wednesday","Thursday","Frid
+ay","Saturday");
    for($sec,$min){$_="0$_"if($_<10);}
    $dst = $isDST?"Daylight Savings Time":"Standard Time";
    $year = $year +1900;
    $timestring= "$weekday[$wday] $mname[$month] $day," . $year . " $h
+our:$min:$sec$x\n";
}

[download]

Replies are listed 'Best First'.
Re: Refresh Display in Perl Tk
by danger (Priest) on Nov 04, 2001 at 01:19 UTC

    If you use the '-textvariable' option (instead of '-text'), you can update the variable and the widget will also update. Also, instead of calling Tk::After, use the 'repeat' method on the Label widget itself. Here is one way (I've replaced your gettime() function with a simple call to localtime() in scalar context to make the date string): 

    #!/usr/bin/perl -w
use strict;
use Tk;

my $top = new MainWindow;
my $text = localtime();
my $id = $top->Label(-textvariable => \$text)->pack;
$id->repeat(1000,sub{$text = localtime()});

MainLoop;
__END__

    [download]
[reply]
[d/l]
      danger, that did it. I just replaced your call to localtime, with my &gettime sub. It works great now, my sub returns the last thing evaluated(the string $timestring)
      Thanks for the help, all!
[reply]
Re: Refresh Display in Perl Tk
by BigJoe (Curate) on Nov 04, 2001 at 01:04 UTC
    I think you need to actually change the text in the label. This should make it refresh. I would suggest looking at this. When I did VB applications this is what we had to do so I think it would be the same for Perl. This has not been tested and it is just my weekend ramblings. 
    #!/usr/bin/perl
use strict;
use Tk;
my $top = new MainWindow;
my $not_stopped = 1;
my $id = "";
while($not_stopped){
   $id = $top->Label(-text =>&gettime);
   sleep(10);
}

    [download]


    --BigJoe

    Learn patience, you must.
    Young PerlMonk, craves Not these things.
    Use the source Luke.
[reply]
[d/l]

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