Phil Thompson wrote:
On Mon, 02 Feb 2009 03:37:13 +0100, GT6 <[email protected]> wrote:
Hi there.
When running the below sample script, and clicking the button, it will
segfault, and I don't understand why or how. I've overwritten a function
in QPlainTextEdit and it should create a new document, set the
PlainTextDocumentLayout and then set the document on the QPlainTextEdit
widget. The important part is this (1st way):
newDoc = QtGui.QTextDocument()
newDoc.setDocumentLayout(QtGui.QPlainTextDocumentLayout(newDoc))
self.setDocument(newDoc)
The above segfaults. I also tried this (2nd way):
newDoc = QtGui.QTextDocument()
newDoc.setDocumentLayout(self.documentLayout())
self.setDocument(newDoc)
This one doesn't segfault, but I get this error:
AttributeError: documentLayout
Apart from that, I tried this third option (3rd way):
newDoc = QtGui.QTextDocument()
newDoc.setDocumentLayout(QtGui.QPlainTextDocumentLayout.__init__(newDoc))
self.setDocument(newDoc)
with the only difference from the first one being that __init__ is
called explicitly instead of expecting it to be defaultet. This one
_doesn't_ segfault, but gives this error:
QPlainTextEdit::setDocument: Document set does not support
QPlainTextDocumentLayout
Which makes no sense as not calling __init__ directly shouldn't be any
different than calling it explicitly.
__init__() initialises a class, it doesn't create one.
So, does anyone have any idea why
this is happening? Do you have a bug tracker?
Keep a reference to "newDoc" - it is getting garbage collected too soon.
Phil
Thanks for your help.
Well, that only works once. So I replace the plzsegfault function in the
sample with this (full sample binned here http://rafb.net/p/P6sqML59.html):
def plzsegfault(self):
self.newDoc = QtGui.QTextDocument()
self.newDoc.setDocumentLayout(QtGui.QPlainTextDocumentLayout(self.newDoc))
# First way
self.setDocument(self.newDoc)
Then, I can safely click the button once, and it also does what I expect
it to do, but clicking the button a second time will again segfault.
What I'm trying to do is that clicking the button will clear the
textfield and make a new document and display it. Do I really have to
care about the document names? I *could* implement a counter and have
all the documents have different names but I don't really need those
specific names in the future. I just need the textfield to discard the
old one and get a new one, everytime the button is clicked. The only
reference to the document that I use lateron is self.document(). I don't
need the name...
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