Re: [Pythoncard-users] How to keep the GUI from freezing while threading

[Tony C. <cap...@gm...>]

I've found the problem.
My call to wx.SafeYield() didn't include self (which is an instance of
the GUI class)
When I changed the call to wx.SafeYield(self) the GUI no longer
freezes while class2 is processing files.

thanks

On Nov 17, 2007 8:41 AM, Kevin Altis <al...@se...> wrote:
> In general, you can't do anything long running in an event handler or
> it will lock your program up as you found. In your case, you should
> take a look at some of the samples and documentation that cover the
> Python thread and Queue modules. Queue is guaranteed to be thread-
> safe so that is what you use to communicate between your GUI thread
> and the thread that is during your long-running work.
>
> http://pythoncard.sourceforge.net/timers-threads.html
>
> Samples that use threads are: chat, jabberChat, webgrabber, and
> webserver.
>
> You'll probably find doing some searches for code snippets and topics
> with the findfiles tool useful.
>
> http://pythoncard.sourceforge.net/findfiles.html
>
> Simply set the directory to search to your copy of PythonCard and
> then look for appropriate topics like thread and Queue.
>
> ka
>
>
> On Nov 16, 2007, at 4:17 PM, Tony Cappellini wrote:
>
> > I've got 2 classes in my Pythoncard program.
> >
> > The GUI is handled in class1 and some file processing is handled in
> > class2.
> >
> > Class2 executes an external program in a thread, and loops waiting for
> > the thread to finish.
> > In that loop, I call a method in class1 which calls wx.safeYield().
> >
> > The external program is processing some text files, and the GUI lets
> > the user choose which files to process and passes those files as args
> > to the external program.
> >
> > While the gui is looping passing a new filename to the program, my
> > Pythoncard GUI is unresponsive. That is, I cannot move it with the
> > mouse, nor maximize/minimize it.
> >
> > Class1 passes a callback to class2 to allow class2 to execute a
> > callback which calls wx.SafeYield. That callback can be seen below
> > (guiCallback)
> >
> > This is the method in class2 which executes the external program,
> > in a thread
> >
> >          threadHandle = ManagedThread(ExecutePipedCommand, cmdLine)
> >
> >          while not threadHandle.IsDone():
> >             guiCallback()
> >             time.sleep(.10)
> >
> >
> > ExecutePipedCommand() is just a wrapper class for os.popen()
> > ManagedThread()  is just a wrapper for the functionality in the
> > threading module
> >
> > How should I proceed to keep my pythoncard gui from freezing?
> >
> > Thanks
> >
>