[PyQt] processEvents on QlistWidget operations does nothing

P. Mathé pmathe at neuf.fr
Sun Jan 27 18:37:05 GMT 2008

Le dimanche 27 janvier 2008, Andreas Pakulat a écrit :
> On 27.01.08 16:45:36, P. Mathé wrote:
> > I am sending you this message, originally sent to the PyQt mailing list, as it seems, according to Phil's answer that the problem lies within Qt.
> > As suggested by Phil, I changed the program to make the urllib call from within a different thread, but, if it partially solves the problem, it repaces one line of code by 
> > more than fifty, makes the code almost unreadable, and disconnect the QListWidget from the QProgressBar updates. (the new code is at your disposal).
> > My point I that I just want that QListWidget works as expected , i.e. that when I say "addItem(...)", I see the item in the UI, now, not later , who knows when.
> Uhm, the QListWidget does have the item immediately, however the
> repainting only happens on the next run of the event loop. Calling
> QApplication::processEvents is known to break in certain situations, any
> longer-taking operation that shouldn't block the UI simply belongs into
> a separate thread or process. Its usage is specifically for those who
> know what they're doing.
> Most of the time you're far better off writing a short QThread subclass
> that does the "hard work" and sends either a custom event or simply a
> signal using Qt::QueuedConnection.

I did it : the code is awfully ugly just to replace 1 line of code

> Last but not least: If you want Qt behaviour to be changed, you need to
> write a bugreport to Trolltech.

Thank you, I just did it
> Andreas


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