python GTK 3 Glade 3 Timer

Question

I have a problem with getting a simple timer to work. Whenever I execute the code, it will display the starting time value to countdown from and then count down 1 second. After that, I receive the following error:

Traceback (most recent call last):
  File "C:\Python33\lib\site-packages\gi\overrides\GLib.py", line 633, in <lambda>
    return (lambda data: callback(*data), user_data)
TypeError: 'bool' object is not callable

Below is my code:

from gi.repository import Gtk, GObject

class Main:

    def __init__(self):
    # create an instance of the builder

    self.builder = Gtk.Builder()
    self.builder.add_from_file('Main_ver_c.glade')
    self.builder.connect_signals(self)

    # Setup the main window
    self.window = self.builder.get_object("program_main")
    self.window.set_title("Automated Benchtop Medical Device Cleaner")
    self.window.show_all()

    # Setup Timer
    self.labelcycle = self.builder.get_object('stage_time')

    # Closes program on 'X' press
    def on_DeleteWindow(self, object, data=None):
        print ("quit with cancel")
        Gtk.main_quit()

    # Displays Timer
    def displaytimer(self,time):
        state = True
        self.labelcycle.set_text(str(time))
        print(time)
        time -= 1
        print(time)
        if time < 0:
            state = False
            print("timer stop")
        return True

    # Initialize Timer
    def startcycletimer(self, counter):
        GObject.timeout_add_seconds(1, self.displaytimer(counter))

if __name__ == '__main__':
    main = Main()
    main.startcycletimer(5)
    Gtk.main()

Answer 1

I haven't really used PyGTK before, but from what I see the issue is most probably in the startcycletimer method:

It should rather be GObject.timeout_add_seconds(1, self.displaytimer) instead of GObject.timeout_add_seconds(1, self.displaytimer(counter)).

You need to pass the caller to the function and not the output.