Convert a class into a QWidget and the methods into push buttons.

classgui.py

from __future__ import annotations
import inspect
from magicgui import magicgui
import napari
from qtpy.QtWidgets import QPushButton, QWidget, QVBoxLayout

# Usage:
# >>> viewer = napari.Viewer()
# >>> cgui = ClassGui(viewer)
# >>> @cgui.from_class
# >>> class MyClass:
# >>>     ....
# >>> viewer.window.add_dock_widget(cgui)

class ClassGui(QWidget):
    def __init__(self, viewer:"napari.Viewer"=None):
        if viewer is not None:
            self.viewer = viewer
            parent = viewer.window._qt_window
        else:
            parent = None
        
        super().__init__(parent=parent)
        self.setLayout(QVBoxLayout())
        
        self._current_dock_widget = None
        self.base = None                
    
    def from_class(self, cls=None, *args, **kwargs):
        """
        Make push buttons from a class.
        """        
        def wrap_class(cls):    
            self.base = cls(*args, **kwargs)
            for name, f in inspect.getmembers(cls):
                if name.startswith("_"):
                    continue
                func = getattr(self.base, name)
                if callable(func):
                    self.bind_method(func)
            return cls
        return wrap_class if cls is None else wrap_class(cls)
    
    def bind_method(self, func, name=None):
        """
        Make a push button from a class method.
        """ 
        if not callable(func):
            raise TypeError(f"{func} is not callable")
        if name is None:
            name = func.__name__.replace("_", " ")
        
        button = QPushButton(name, parent=self)
        button.setToolTip(func.__doc__)
        
        def update_mgui(*args):
            if self._current_dock_widget:
                self.viewer.window.remove_dock_widget(self._current_dock_widget)
            mgui = magicgui(func)
            self._current_dock_widget = self.viewer.window.add_dock_widget(mgui, name=name)
            self._current_dock_widget.setFloating(True)
            return None
        
        button.clicked.connect(update_mgui)
        
        self.layout().addWidget(button)
        return None