Need help with custom enum properties in Qt6 Designer

[Phil Thompson]

On 01/03/2024 17:24, Ivan Sinkarenko wrote:
> Hi everybody,
> 
> I've seen there's been a lot happening with enums in PyQt6,
> and I've managed to adapt to most of the problems, except one.
> I cannot figure out how to make custom enums work in custom widgets
> that are exposed to Qt Designer.
> 
> This is my simplified code:
> 
> ----------------------------------------------------------------------
> import enum
> from PyQt6 import QtDesigner, QtGui, QtWidgets, QtCore
> 
> class MyWidget(QtWidgets.QWidget):
> 
>     @QtCore.pyqtEnum
>     class MyEnum(enum.IntEnum):
>         ONE = enum.auto()
>         TWO = enum.auto()
> 
>     def __init__(self, *args, **kwargs) -> None:
>         super().__init__(*args, **kwargs)
>         self._prop = MyWidget.MyEnum.TWO
> 
>     @QtCore.pyqtProperty(MyEnum)
>     def prop(self):
>         print(f'Getting property val {self._prop}')
>         return self._prop
> 
>     @prop.setter
>     def prop(self, new_val):
>         print(f'Setting new property val {new_val}')
>         self._prop = new_val
> 
> class Plugin(QtDesigner.QPyDesignerCustomWidgetPlugin):
> 
>     def name(self):
>         return "MyWidget"
> 
>     def group(self):
>         return "Buttons"
> 
>     def isContainer(self):
>         return False
> 
>     def createWidget(self, parent):
>         return MyWidget(parent)
> 
>     def icon(self):
>         return QtGui.QIcon()
> 
>     def toolTip(self):
>         return ""
> 
>     def whatsThis(self):
>         return ""
> 
>     def includeFile(self):
>         return "pyqt6_enum_designer_poc_plugin"
> ----------------------------------------------------------------------
> 
> I want an enum property to be displayed in the PropertySheet.
> It's correctly represented by a combobox showing ONE and TWO as
> available options.
> 
> TWO is correctly selected by default. However, when in Property sheet
> I try to set it to ONE,
> as soon as I click away from there, it's reset back to TWO. In fact,
> the setter does not get called,
> since the message inside is never printed. (Getter message is being 
> printed).
> 
> Properties do work without issues, if they have built-in types, such as 
> QColor,
> or even native enums, such as Qt.Orientation.
> 
> To try this code, you can save this code to
> "pyqt6_enum_designer_poc_plugin.py" and run like so:
> PYQTDESIGNERPATH=$(pwd) designer
> 
> I use Qt Designer 6.6.2 and:
> - PyQt6         6.6.1
> - PyQt6-Qt6  6.6.2
> - PyQt6-sip   13.6.0
> 
> (Also tried with PyQt6-6.5.3 PyQt6-Qt6-6.5.3, same result)
> 
> There used to be a way to make this work in PyQt5, but in PyQt6 I
> tried multiple approaches without luck.
> If anybody knows the correct path, that would be very appreciated!
> 
> Thanks,
> Ivan

This is ringing a faint bell. I looked at it a long time ago and found 
that Designer was just not making the normal call to write the changed 
property value, maybe due to some sort of "optimisation". There may be 
something wrong in the way that PyQt creates the QMetaObject for the 
Python class but I never managed to get to the bottom of it.

Sorry for not being more helpful.

Phil