Text widget updates only after calling method exits (threading issue?)

[Eric Brunel]

On Wed, 12 Dec 2007 02:58:37 +0100, mariox19 <mariodiana at gmail.com> wrote:

> Are Tkinter widgets running on their own thread?

No. And usually, GUI toolkits and threads don't mix well...

> If I try to make a simple application that will print the letters A to
> Z to a Tkinter Text widget, and I space the printing of each letter by
> 1 second, it seems no text will appear in the Text widget until the
> method exits.
>
> Take a look at this snippet:
>
>     # Assume I have created no threads other than the one that comes
> with Main
>
>     def printToTkinterTextWidget(text):
>         """
>         Prints A-Z to the Text widget, 1 letter per second.
>         """
>         # Problem: no text appears in the widget until 26 seconds has
> elapsed
>         for aNumber in range(65, 91):
>             self.textWidget.insert(END, text)
>             time.sleep(1)

time.sleep will not give back the control to the Tkinter mainloop, so your  
text widget won't be refreshed on screen. Try:
self.textWidget.update_idletasks()
before the sleep.

HTH
-- 
python -c "print ''.join([chr(154 - ord(c)) for c in  
'U(17zX(%,5.zmz5(17l8(%,5.Z*(93-965$l7+-'])"