Qt for Python DBusIntegration

To get PySide2 and DBus working together you can use the glib mainloop integration already done in dbus-python.

The examples below show how to export Qt objects to Python and emit a D-Bus signal when a Qt signal is emitted. The code comments explain what you need to know about PySide2 and D-Bus.

Also refer to the dbus-python tutorial.

D-Bus Client

#!/usr/bin/env python # -'''- coding: utf-8 -'''-  # DBUS Client using PySide2 integration  import sys from traceback import print_exc  # import python dbus module import dbus # import python dbus GLib mainloop support import dbus.mainloop.glib # import QtCore from PySide2.QtCore import *  # signal handler def button_clicked():  print("button clicked")  # main function if __name__ == '__main__':  # Enable glib main loop support  dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)  # Get the session bus  bus = dbus.SessionBus()   try:  # Get the remote object  remote_object = bus.get_object("com.example.SampleService",  "/DBusWidget")  # Get the remote interface for the remote object  iface = dbus.Interface(remote_object, "com.example.SampleWidget")  except dbus.DBusException:  print_exc()  sys.exit(1)   # Start the application  app = QCoreApplication([])   # Call some methods of the remote interface  iface.show()  iface.setText("Emit signal")  # connect the DBus signal clicked to the function button_clicked  iface.connect_to_signal("clicked", button_clicked)  iface.connect_to_signal("lastWindowClosed", app.quit)   # enter in the main loop  app.exec_() 

D-Bus Server

#!/usr/bin/env python #-'''- coding: utf-8 -'''-  # DBUS Server Example of use PySide2 with dbus-python library  import dbus import dbus.service import dbus.mainloop.glib import random  from PySide2.QtCore import * from PySide2.QtWidgets import QPushButton, QApplication  # The adaptor, MUST inherit dbus.service.Object class DBusWidget(dbus.service.Object):  def __init__(self, name, session):  # export this object to dbus  dbus.service.Object.__init__(self, name, session)   # create a simple widget  self.widget = QPushButton()  self.widget.resize(200, 50)   # To export a Qt signal as a DBus-signal, you need to connect it to  # a method in this class.  # The method MUST have the signal annotation, so dbus-python will  # export it as a dbus-signal  QObject.connect(self.widget, SIGNAL ("clicked()"), self.clicked)  QObject.connect(QApplication.instance(), SIGNAL ("lastWindowClosed()"),  self.lastWindowClosed)   # You can export methods to dbus like you do in python-dbus.  @dbus.service.method("com.example.SampleWidget", in_signature='', out_signature='')  def show(self):  self.widget.show()   # Another method… now with a parameter  @dbus.service.method("com.example.SampleWidget", in_signature='s', out_signature='')  def setText(self, value):  self.widget.setText(value)   # Another one…  @dbus.service.method("com.example.SampleWidget", in_signature='', out_signature='')  def exit(self):  qApp().quit()   # A signal that will be exported to dbus  @dbus.service.signal("com.example.SampleWidget", signature='')  def clicked(self):  pass   # Another signal that will be exported to dbus  @dbus.service.signal("com.example.SampleWidget", signature='')  def lastWindowClosed(self):  pass  if __name__ == "__main__":  print("holi")  app = QApplication([])  # Use qt/glib mainloop integration to get dbus mainloop working  dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)   session_bus = dbus.SessionBus()  print(session_bus)  # Export the service  name = dbus.service.BusName("com.example.SampleService", session_bus)  # Export the object  widget = DBusWidget(session_bus, '/DBusWidget')   print("Running 

Running the examples

Copy the client code to a file called example-client.py and the server to a file called example-server.py and type:

python example-server.py & python example-client.py 

A small window should appear on screen. Click on the button to emit a Qt signal. The signal will be converted to a D-Bus signal that will be caught by our D-Bus client.