Repository navigation
super() does not work for Qt classes #39
Description
Activity
When taking the above example, you can always do
QDoubleValidator.setRange(self, minimum, maximum, decimals+1)
instead.I had a problem yesterday with
sizeHintfrom QWidget. I was aware of the variant you described forQDoubleValidatorbut I had problems with a property.My Class is a simple Code block which should resize the content of the text.
Here is a rough version (not working 100% for the resize).
class Code(QPlainTextEdit): def __init__(self, parent=None): super(Code, self).__init__(parent) def heightForWidth(self): # some calc here return 30 def sizeHint(self): original_hint = super(QWidget, self).sizeHint # does not work as described in the description of the issue original_hint = QPlainTextEdit.sizeHint(self) # exception: QSize object no callable original_hint = QPlainTextEdit(self).sizeHint # the only which seems to work return QSize(original_hint.width(), self.heightForWidth(original_hint.width()))
original_hint = QPlainTextEdit(self).sizeHint # the only which seems to workwas the only version which was working or in other words don't throw an exception. It creates a second QPlainTextEdit as far as I can see.What iss the correct way to get a property?
QPlainTextEdit(self).sizeHint
is probably not what you want; this should create a new QPlainTextEdit with your instance as the parent.
QPlainTextEdit.sizeHint(self)
would be the correct solution, but PythonQt seems to treat sizeHint like a property, though only instances have properties, not their classes. I wonder which QSize is returned here. Anyway, I consider this a bug, but no promises by me if and when this will be fixed.So, I believe there is currently no way to do this correctly for properties.
I just want to share some insights into this issue, I currently have no intention to fix the issue, as that would be somewhat complicated.
This is an example of what does not work:
The problem boils down to the fact that the method lookup of super() directly accesses the internal tp_dict member of the super classes, which is only filled to an absolute minimum by PythonQt (for performance reasons). Everything else is delivered through tp_getattro calls, but this does not work for super.
I discussed with Florian Link what would have to be done to fill the tp_dict.
We both agreed that this change is somewhat tricky and probably currently not worthwhile.