Need a Tk expert 1

[timtrust123]

I would like the text on a button to update while a sub is running. I have linked the button text to a variable in the example below hoping it would update during the sub but it does not. How can I update the button text during the sub running. (i'm using win NT )

use Tk;
$info = "start";
$mw = MainWindow->new;
$i = 0;
$b = $mw->Button(-text=> $info)->pack();
$b->configure (-command => \&push_button);

MainLoop;


sub push_button
{
$i = 0;
while ($i < 1000000){$i++}
$info = "first stage";
$i = 0;
while ($i <100000){$i++}
$info = "second stage";
$i = 0;
while ($i <100000){$i++}
$info = "third stage";
print "done\n$info";
}

 

[timtrust123]

I have the same problem updating a label
Any ideas out there????

 

[parkers]

Hi Tim

To update the text on the button when pressed you need to reconfigure yot button ... to do this you should change your sub-routine to the following (or equivalent):

sub push_button
{
++$counter;
$b->configure (-text=>"Button Press: $counter");
}

Remember that Tk is event driven so having the button update dynamically over time will require a bit more effort ... you should read the following sample from the O'Reilly Web Site regarding the Anatomy of the MainLoop for more information...

http://www.oreilly.com/catalog/mastperltk/chapter/ch15.html

hope this helps ...

 

[parkers]

Hi tim,

Rab54's thread, thread219-875531 ... got me thinking, if you update your code to the following (or similar) then the button will update as required:

use Tk;
$info = "start";
$mw = MainWindow->new;
$i = 0;
$b = $mw->Button(-text=> $info)->pack();
$b->configure (-command => \&push_button);

MainLoop;


sub push_button
{
$i = 0;
while ($i < 1000000){$i++}
[b][COLOR=red]$b->configure(-text=>"first stage");
$b->update;[/color][/b]
$i = 0;
while ($i <10000000){$i++}
[b][COLOR=red]$b->configure(-text=>"second stage");
$b->update;[/color][/b]
$i=0;
while ($i <1000000){$i++}
[b][COLOR=red]$b->configure(-text=>"third stage");
$b->update;[/color][/b]
}

Basically the button widget ($b) is being refreshed after every while loop...

hope this helps

 

[timtrust123]

Many thanks to Parkers.
This is exactly what I wanted. I very much appreciate you taking time to read my posting and suggesting the solution.
Many thanks....

 

[parkers]

glad to help ...

I'm interested in developing my Tk skills also !