Add compatibility with pyside2

[laser101]

Hi,

I've successfully used the PyQt5Singleton class in my PyQt5 projects, but am currently looking at a project that uses qtpy to abstract away PyQ5 and pyside2, allowing either frameworks to be used.

Unfortunately I haven't been able to get PyQt5Singleton to work with pyside2 (either directly, or via qtpy). Do you have any suggestions for how this might be approached.

Thanks,

Russ

[fmassucci]

Did you manage to implement it with PySide?

[nrbnlulu]

here is a PySide6 implementation

class QSingleton(type(QObject)):
    def __init__(cls, name, bases, dict):
        super().__init__(name, bases, dict)
        cls.instance=None

    def __call__(cls,*args,**kw):
        if cls.instance is None:
            cls.instance=super().__call__(*args, **kw)
        return cls.instance
# Usage
class Foo(QObject, metaclass=QSingleton):
    ...

@fmassucci