Question

i have tkinter class and some functions in it, (assume all other functions are present to initiate the GUI). what i have done i have started one self.function as a thread from other self.function and in threaded function upon error i want to use tkMessageBox.showerror(‘Some Error’) but this does not work in threaded function and my program got stuck. msgbox is working in other function.

import threading
from Tkinter import *
import Pmw
import tkMessageBox

class tkinter_ui:
      def __init__(self, title=''):
      ... assume all functions are present ...

      def login(self, username, password)
          if password == "":
             tkMessageBox.showerror('Login Error', 'password required') # but on this msg box program become unresponsive why???

      def initiateLogin(self)
          tkMessageBox.showinfo('Thread', 'Started')   #you see this msg box works
          self.t = threading.Timer(1, self.login)
          self.t.start()

Answer 1

tkinter is not thread safe — you can’t reliably call any tkinter functions from any thread other than the one in which you initialized tkinter.