[Tutor] cannot get a label message to display immediately

Bill Allen wallenpb at gmail.com
Sat Aug 15 07:44:58 CEST 2015

On Fri, Aug 14, 2015 at 3:06 PM, Alan Gauld <alan.gauld at btinternet.com>

> That's the problem right there. You should never kick of an event handler
> that takes a long time to run. Either:
> 1) Kick of a separate thread to do the back end processing
> 2) break the function into short chunks and use a timer
> (after() in Tkinter) to repeatedly fire the function
> (this is the traditional GUI approach)
> 3) In Python 3.4 use asyncore to create an asynchronous event
> loop and feed the functions into that.
> ...
> def long_handler()
>    update_status()    # change the GUI
>    getItem(data)      # fetch one item from data
>    processItem(item)  # process one item,
>    if data:           # is there any more?
>       after(20, long_handler)  # then go again after 20ms
> Follow my photo-blog on Flickr at:
> http://www.flickr.com/photos/alangauldphotos
> Alan and everyone that responded,

Excellent information!  It was the concepts that I was falling short on an
this helped me a great deal.  In my particular situation, I found using the
after() method indeed worked just fine and was quite simple to implement.
In my case, as simple as this:

def processing(*args):   #my initial button click calls this
    '''  display messages in the information message_frame while the data
is processed '''
    info.set('PROCESSING, PLEASE WAIT...')   #the label message I was
wanting to get out there to the user
    root.after(1000, process_part)  #the long running data process

Thanks again!
Bill Allen

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