Il giorno mar, 14/12/2010 alle 18.02 +0100, Hans Meine ha scritto:
> Am Dienstag 14 Dezember 2010, 17:05:42 schrieb Darryl Wallace:
> > One of the things I've found in this regard has to do with Python and
> > garbage collection. If the reference count to certain objects does not go
> > to zero then the item will not be garbage collected.
> >
> > Ensure that the objects that you want cleaned up have no references to
> > them. I've found that setting widgets' parents to None and then setting
> > that variable to None often does the trick.
> >
> > Anyone else have tips on garbage collection with PyQt???
>
> I also use sip.delete(obj) or obj.deleteLater() from time to time.
>
> Also I have a large number of helper functions based on the gc module, e.g.
> the ones below. These are very useful, use like this:
>
> h1 = gcHistogram()
> ... # some long-running calculations which seem to leak memory
> h2 = gcHistogram()
> diffHists(h1, h2)
>
> This will output the *types* of objects that have been created in the
> meantime, along with their counts. Sometimes, this will not help much
> though,
> e.g. if you use standard python lists a lot. (It might make sense to use
> specialized classes derived from list anyway, no?)
>
> def gcHistogram():
> """Returns per-class counts of existing objects."""
> result = {}
> for o in gc.get_objects():
> t = type(o)
> count = result.get(t, 0)
> result[t] = count + 1
> return result
>
> def diffHists(h1, h2):
> """Prints differences between two results of gcHistogram()."""
> for k in h1:
> if h1[k] != h2[k]:
> print "%s: %d -> %d (%s%d)" % (
> k, h1[k], h2[k], h2[k] > h1[k] and "+" or "",
> h2[k] -
> h1[k])
>
really useful thanks!
Using these functions I found that if I do something like this:
self.ui.lineEdit.mouseReleaseEvent=self....
I have to manually do:
self.ui.lineEdit.mouseReleaseEvent=None
to get the widget deleted, this seems a pyqt bug,
Nicola
> HTH,
> Hans
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