Indeterminate Progress Bar not moving - python-3.x

Question

I can not get the progress bar to move. Solutions offered in other post were very convoluted. The original task was loading a workbook with openpyxl, but I have substituted a 3 second delay which presents the same problem. update() does not move the progress bar. update_idletask() does not render the window correctly. mainloop() works, but does not stop working.
I am running python 3.7.9 on windows 10.
from tkinter import *
from tkinter import ttk
import time
# from openpyxl import load_workbook
class ProgressBarIn:
def __init__(self, title="", label="", text=""):
self.title = title
self.label = label
self.text = text
self.pb_root = Tk() # create a window for the progress bar
self.pb_label = Label(self.pb_root, text=self.label) # make label for progress bar
self.pb = ttk.Progressbar(self.pb_root, length=400, mode="indeterminate") # create progress bar
self.pb_text = Label(self.pb_root, text=self.text, anchor="w")
def set_up(self):
# titlebar_icon(self.pb_root) # place icon in titlebar
self.pb_root.title(self.title)
self.pb_label.grid(row=0, column=0, sticky="w")
self.pb.grid(row=1, column=0, sticky="w")
self.pb_text.grid(row=2, column=0, sticky="w")
self.pb.start()
self.pb_root.update()
# self.pb_root.update_idletasks()
# self.pb_root.mainloop()
def stop(self):
self.pb.stop() # stop and destroy the progress bar
self.pb_label.destroy() # destroy the label for the progress bar
self.pb.destroy()
self.pb_root.destroy()
def my_function():
pb = ProgressBarIn(title="hey now", label="hold on", text="hello there")
pb.set_up()
time.sleep(3)
wb = "hello in three seconds"
# wb = load_workbook(file_path)
pb.stop()
return wb
print(my_function())

Answer 1

This solution uses a global as a flag which communicates to the progress bar when to stop updating after the multithread has finished it's task. The WaitUp class creates an attribute called "self.i_waited_for_this" which holds the result of the multithread's task and will be called to retrieve it once the multithread has finished. The progress bar uses time.sleep() to pause between incrementing the value of the progress bar while the global flag variable is True and stops once line 19 is read and the variable is changed to False. Just to be clear, the progress bar is running on the main thread, not an additional thread since tkinter and multithreading don't mix.
from tkinter import *
from tkinter import ttk
from threading import *
import time
class WaitUp(Thread): # Define a new subclass of the Thread class of the Thread Module.
def __init__(self, secs=0):
Thread.__init__(self) # Override the __init__
self.secs = secs
self.i_waited_for_this = ""
def run(self):
global pb_flag # this tells the progress bar to stop
for i in range(self.secs): # print one number each second / replace with your task
print(i)
time.sleep(1)
pb_flag = False
self.i_waited_for_this = "it is done" # result of the task / replace with object or variable you want to pass
class ProgressBarIn:
def __init__(self, title="", label="", text=""):
self.title = title # Build the progress bar
self.label = label
self.text = text
self.pb_root = Tk() # create a window for the progress bar
self.pb_label = Label(self.pb_root, text=self.label) # make label for progress bar
self.pb = ttk.Progressbar(self.pb_root, length=400, mode="indeterminate") # create progress bar
self.pb_text = Label(self.pb_root, text=self.text, anchor="w")
def startup(self):
self.pb_root.title(self.title)
self.pb_label.grid(row=0, column=0, sticky="w")
self.pb.grid(row=1, column=0, sticky="w")
self.pb_text.grid(row=2, column=0, sticky="w")
while pb_flag: # move the progress bar until multithread reaches line 19
self.pb_root.update()
self.pb['value'] += 1
time.sleep(.1)
def stop(self):
self.pb.stop() # stop and destroy the progress bar
self.pb_label.destroy() # destroy the label for the progress bar
self.pb.destroy()
self.pb_root.destroy()
def my_function():
global pb_flag
pb_flag = True
t1 = ProgressBarIn(title="hey now", label="hold on", text="hello there")
t2 = WaitUp(secs=5) # pass the progress bar object
t2.start() # use start() instead of run() for threading module
t1.startup() # start the progress bar
t2.join() # wait for WaitUp to finish before proceeding
t1.stop() # destroy the progress bar object
return t2.i_waited_for_this
# delclare global variables
global pb_flag # this tells the progress bar to stop
print(my_function())