How to use two threads (GUI and backend)

[pozz]

Il 26/10/2016 09:13, pozz ha scritto:
 > [...]
> What is the best approach to use in my scenario (GUI and backend
> communication)?

I just found this[1] page, where the thread approach is explained with 
the following code:

---
   import threading
   import time

   from gi.repository import GLib, Gtk, GObject


   def app_main():
     win = Gtk.Window(default_height=50, default_width=300)
     win.connect("delete-event", Gtk.main_quit)

     progress = Gtk.ProgressBar(show_text=True)
     win.add(progress)

     def update_progess(i):
       progress.pulse()
       progress.set_text(str(i))
       return False

     def example_target():
       for i in range(50):
         GLib.idle_add(update_progess, i)
         time.sleep(0.2)

     win.show_all()

     thread = threading.Thread(target=example_target)
     thread.daemon = True
     thread.start()


   if __name__ == "__main__":
     # Calling GObject.threads_init() is not needed for PyGObject 3.10.2+
     GObject.threads_init()

     app_main()
---

This is similar to my approach, with a main difference: the callback 
update_progress() added to the GLib idle loop (so executed in the main 
GUI thread) receives all the data as arguments (the value i to write as 
text in the progress widget).

In my case, I have many many properties of the remote device. So my 
first idea is to get directly the value by accessing variables changed 
during backend thread... I think this is wrong.





[1] https://wiki.gnome.org/Projects/PyGObject/Threading