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

[Kevin A. <al...@se...>]

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
>