On Tue, May 25, 2010 at 08:41:37AM +0200, orcim wrote:
> Alessandro Dentella ha scritto:
>
> On Fri, May 21, 2010 at 05:57:00PM +0200, Alessandro Dentella wrote:
>
>
> Hi,
>
> I'm trying to figure out the correct way to delete a class that builds
> GUI.
>
> I was not able to delete the object from a callback in a clean way.
>
> The following code should demostrate what I mean::
>
> import weakref
> import gtk
> import gobject
>
> class A(object): pass
>
>
> class G(object):
> def __init__(self):
> self.a = A()
> self.w = gtk.Window()
> self.w.show()
> self.w.connect_after('delete-event', self.delete_event_cb)
>
> def delete_event_cb(self, win, ev):
> print 'killed'
> del self
> print "s", s() # I'd like to see this to become None
> gtk.main_quit()
>
> g = G()
>
> s = weakref.ref(g.a)
>
> gtk.main()
>
> My goal is to create a class 'G' that will destroy itself completely
> when the window it holds receives a "delete_event".
>
> As written in the comment, I'd like to see that the weakref to an
> element
> inside the instance 'g' should be None after deletion of 'g'. But
> it's not!
>
> Deleteing the object prints:
>
> san...@bluff: $ python test_mem.py
> killed
> s <__main__.A object at 0x8329eec>
>
> If I get rid of 'self'in the callback, everithing works but that makes
> it impossible to put the function inside the class.
>
> If I use a delete_event_cb as a separate function I manage to destroy
> it if
> I don't pass the g object as argument to the callbac (ie: making it
> global)
> but clearly that's a far less usefull setup.
>
> What's the best practice to delete compound widgets?
>
>
>
> Further tests on this showed me that if I set data on a widget
> (e.g. using set_data) that contitues a strong reference that will not let
> the gc to delete the object::
>
> import gc
> import sys
> import weakref
> import gtk
>
> class G(object):
> def __init__(self):
> self.w = gtk.Window()
> self.w.show()
> self.w.set_data('obj', self) # this reference keeps 's'
> "alive"
> self.w.connect_after('delete-event', self.delete_event_cb)
> self.w.connect('enter-notify-event', self.enter_event_cb)
>
> def delete_event_cb(self, win, ev):
> print 'killed'
>
> def enter_event_cb(self, win, ev):
> global s
> print 'enter', s()
>
>
> s = weakref.ref(G())
> print s()
>
> try:
> gtk.main()
> except KeyboardInterrupt:
> print s()
> sys.exit(1)
>
> I'd say this is a bug, am I wrong? is this a known problem?
> That clearly leads to memory leaks.
>
> Any hints?
>
> sandro
> *:-)
>
>
>
>
> probably there 'a reference object gtk still alive somewhere
> ciao Loris
Yes, that's exactly what I would consider a bug. I hoped this list could
comment on this as it's a problem that should hit *anybody* writing
application with PyGTK...
I verify that each widow I open increases the amount of RAM needed and in no
may I can decrease it when closing the window.
I may have done some serious error but I don't find any best practice on
this and I consider this a very important issue.
sandro
--
Sandro Dentella *:-)
http://sqlkit.argolinux.org SQLkit home page - PyGTK/python/sqlalchemy
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