PyQt4 - widget signal trouble

Phil Thompson phil at riverbankcomputing.com
Sun Apr 26 15:04:47 CEST 2009


On Sun, 26 Apr 2009 14:46:14 +0200, Marco Bizzarri
<marco.bizzarri at gmail.com> wrote:
> On Sun, Apr 26, 2009 at 12:38 PM, Joacim Thomassen
> <joacim at net.homelinux.org> wrote:
>> Den Sat, 25 Apr 2009 23:47:57 +0200, skrev Marco Bizzarri:
>>
>>
>> Hello Marco,
>>
>> python's fcntl() call the regular C fcntl() function and as stated in
the
>> manual pages for C fcntl:
>>
>> ----------- Snippet from fcntl man pages ----------------
>>
>> File and directory change notification (dnotify)
>>       F_NOTIFY (long)
>>              (Linux  2.4 onwards) Provide notification when the
>>                      directory referred to by fd or any of
the
>> files that it
>>                      contains is changed.  The  events  to
>>  be  notified  are
>>              specified in arg, which is a bit mask specified by
>> ORing
>>                      together zero or more of the following
>> bits:
>>
>>              DN_MODIFY   A file was modified (write, pwrite,
>> writev,
>>                                                
>>       truncate, ftruncate).
>> ------------- End snippet of fcntl man pages -------------------
>>
>> The fact that my program actually trigger a signal as the monitored
>> directoy's image.jpg file change confirm that this part of the code do
>> work. I do get "Change happened!" as i manually do a "cp another.jpg
>> image.jpg", but this action is first seen after I close my application
>> window. (I do not get "Change happened!" if I don't do my manual cp
>> command. :-) )
>>
>> Personaly I believe this has something to do with the GUI/Qt4 part that
I
>> have not understood. Something about how a widget repaint itself or
>> something in that direction.
>>
>> Best regards,
>> Joacim
>> --
>> http://mail.python.org/mailman/listinfo/python-list
>>
> 
> 
> You're right: I've found the following answer googling:
> 
> http://mail.python.org/pipermail/python-list/2007-February/597617.html
> 
> 
> indeed, addind a startTimer() to your code, makes it works ;).

Alternatively, use QFileSystemWatcher instead.

Phil



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