Re: How to keep the GUI from freezing while threading

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
>

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