superqt/docs/combobox.md

ComboBox

Enum Combo Box

QEnumComboBox is a variant of QComboBox that populates the items in the combobox based on a python Enum class. In addition to all the methods provided by QComboBox, this subclass adds the methods enumClass/setEnumClass to get/set the current Enum class represented by the combobox, and currentEnum/setCurrentEnum to get/set the current Enum member in the combobox. There is also a new signal currentEnumChanged(enum) analogous to currentIndexChanged and currentTextChanged.

Method like insertItem and addItem are blocked and try of its usage will end with RuntimeError

from enum import Enum

from superqt import QEnumComboBox

class SampleEnum(Enum):
    first = 1
    second = 2
    third = 3

# as usual:
# you must create a QApplication before create a widget.

combo = QEnumComboBox()
combo.setEnumClass(SampleEnum)

other option is to use optional enum_class argument of constructor and change

combo = QEnumComboBox()
combo.setEnumClass(SampleEnum)

to

combo = QEnumComboBox(enum_class=SampleEnum)

Allow None

QEnumComboBox allow using Optional type annotation:

from enum import Enum

from superqt import QEnumComboBox

class SampleEnum(Enum):
    first = 1
    second = 2
    third = 3

# as usual:
# you must create a QApplication before create a widget.

combo = QEnumComboBox()
combo.setEnumClass(SampleEnum, allow_none=True)

In this case there is added option ---- and currentEnum will return None for it.