[PyQt] Strangeness with signals and slots in PyQt4 QLineEdit
Johannes Lochmann (gmail)
johannes.lochmann at googlemail.com
Thu Aug 16 17:41:25 BST 2007
On Thursday 16 August 2007 16:20, David Boddie wrote:
> On Thu Aug 16 14:57:37 BST 2007, Johannes Lochmann wrote:
Thank you for the quick and thorough response - that cleared things up mighty!
> In the slots in your Widget class, you're just assigning the "txt" values
> to the attributes in the instance of the Data class:
> In C++, this would work perfectly because QString objects are copied when
> they are modified, so your copies in the "data" object will be safe.
> In Python, each QString is simply bound to the "a", "b" and "c" attributes.
> When each slot returns, the QString is still referenced, but could be
> changed elsewhere, and the "copy on write" semantics of Qt don't apply.
OK, now knowing this particular detail made everything clear!
> Basically, you have to explicitly copy the "txt" values passed to the
> self.data.a = QString(txt) # or use unicode(txt)
As I have to convert everything to utf-8 for database storage this is no big
Thank you for your quick help!
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