This class decorator is equivalent to the Q_ENUM macro from Qt. The decorator is used to register an Enum to the meta-object system, which is available via QObject.staticMetaObject. The enumerator must be in a QObject derived class to be registered.


from enum import Enum, Flag, auto

from PySide2.QtCore import QEnum, QFlag, QObject

class Demo(QObject):

    class Orientation(Enum):
        North, East, South, West = range(4)

    class Color(Flag):
        RED = auto()
        BLUE = auto()
        GREEN = auto()
        WHITE = RED | BLUE | GREEN

    QFlag(Color)    # identical to @QFlag usage


QEnum registers a Python Enum derived class. QFlag treats a variation of the Python Enum, the Flag class.

Please do not confuse that with the Qt QFlags concept. Python does not use that concept, it has its own class hierarchy, instead. For more details, see the Python enum documentation.

Details about Qt Flags:

There are some small differences between Qt flags and Python flags. In Qt, we have for instance these declarations:

enum    QtGui::RenderHint { Antialiasing, TextAntialiasing, SmoothPixmapTransform,
                            HighQualityAntialiasing, NonCosmeticDefaultPen }
flags   QtGui::RenderHints

The equivalent Python notation would look like this:

class RenderHints(enum.Flag)
    Antialiasing = auto()
    TextAntialiasing = auto()
    SmoothPixmapTransform = auto()
    HighQualityAntialiasing = auto()
    NonCosmeticDefaultPen = auto()

As another example, the Qt::AlignmentFlag flag has ‘AlignmentFlag’ as the enum name, but ‘Alignment’ as the type name. Non flag enums have the same type and enum names.

enum Qt::AlignmentFlag
flags Qt::Alignment

The Python way to specify this would be

class Alignment(enum.Flag):

We are considering to map all builtin enums and flags to Python enums as well in a later release.