Alex provided some good info. The findfiles tool, hopalong, life, and 
spirograph samples all make use of SafeYield so I suggest taking a look 
at those for various ways of starting a long running process that 
doesn't involve using threads. I particularly like the use of a 
generator in the hopalong sample and just like the other samples 
mentioned above it handles starting a routine and allowing the user to 
stop the execution in a clean way. Other samples such as webgrabber, 
chat, jabberChat, webserver show how to use threads, but using threads 
is more complicated and error-prone and you probably don't need them.

ka
On Jul 9, 2004, at 8:39 AM, Alex Tweedly wrote:

>  At 14:01 09/07/2004 +0200, pieter.coppens@[...].be wrote:
> 
> > Hello,
> >
> > I have the following problem:
> >
> > I'm writing a PythonCard application that has 2 buttons (a start 
> > button and
> > a stop button).
> >
> > When I press the start button, the 'on_cmdStart_mouseClick(self, 
> > event):'
> > function is executed.
> > Now, I want to be able to stop that function at any time by pressing 
> > the
> > STOP button.
> >
> > My problem is now that 'mouseClick'-events are not seen as long as 
> > I'm in
> > the 'on_cmdStart_...' function.
> >
> > Can anyone help me?
> 
>  It's not just mouse-Click events that aren't seen - while your code is 
>  running, no events will be processed.
> 
>  You should read (or re-read to remind yourself) about
>  http://pythoncard.sourceforge.net/timers-threads.html
> 
>  Note in particular the introductory paragraph that says:
> 
> > Most of the top-level code you add to the front ends - your 
> > PythonCard user interfaces - is event handlers. As with programming 
> > with any GUI, event handlers should always complete their job fast, 
> > and return promptly, so they don't 'clog up the works'. PythonCard is 
> > no exception.
> 
>  While an event handler is running, no further events can happen. The 
>  cleanest way to deal with processing that takes a long time is using 
>  threads - and is well explained in that tutorial.
> 
>  If you have a really simple case, you can use the wxApp function Yield 
>  - but read the cautions about its dangers - see the wx documentation 
>  for wxApp::Yield
> 
>  Here's a simple bit of code that shows what this does
> 
>  Notes.
>  1. the work this does to keep it busy is calculate factorials - hey, 
>  I've always wanted a chance to write a recursive factorial function 
>  for a good purpose :-)
>  2. each time round the loop, it calls yield to allow other events to 
>  be processed - without this the Stop button click wouldn't happen, and 
>  in fact the writing and updating of the TextArea would happen.  (try 
>  commenting out the Yield line to see it fail ....)
>  3. the "app" in "app.Yield()" is the global from the main program (not 
>  included here, but the standard name used in the templates).
> 
> 
>      def on_openBackground(self, event):
>          self.results = []
> 
>      def on_Start_mouseClick(self, event):
>          def fact(i):
>              if i<=1: return 1
>              return i * fact(i-1)
> 
>          self.stopping = False
>          for i in range(1000):
>              j = fact(i)
>              s = "%d! is %d" % (i, j)
>  ##            self.results.append(s)
>  ##            self.components.TextArea1.text = "\n".join(self.results)
>              self.components.TextArea1.text = str(i)
>              app.Yield()
>              if self.stopping: break
> 
>      def on_Stop_mouseClick(self, event):
>          self.stopping = True
> 
> 
>  -- Alex.
> 
> 
>  ---
>  Outgoing mail is certified Virus Free.
>  Checked by AVG anti-virus system (http://www.grisoft.com).
>  Version: 6.0.714 / Virus Database: 470 - Release Date: 02/07/2004



-------------------------------------------------------
This SF.Net email sponsored by Black Hat Briefings & Training.
Attend Black Hat Briefings & Training, Las Vegas July 24-29 - 
digital self defense, top technical experts, no vendor pitches, 
unmatched networking opportunities. Visit www.blackhat.com
_______________________________________________
Pythoncard-users mailing list
Pythoncard-users@[...].net
https://lists.sourceforge.net/lists/listinfo/pythoncard-users