How to connect a progress bar to a function?

by

Since tkinter is single threaded, you need another thread to execute your main function without freezing the GUI. One common approach is that the working thread puts the messages into a synchronized object (like a Queue), and the GUI part consumes this messages, updating the progress bar.

The following code is based on a full detailed example on ActiveState:

import tkinter as tk
from tkinter import ttk
import threading
import queue
import time


class App(tk.Tk):

    def __init__(self):
        tk.Tk.__init__(self)
        self.queue = queue.Queue()
        self.listbox = tk.Listbox(self, width=20, height=5)
        self.progressbar = ttk.Progressbar(self, orient="horizontal",
                                           length=300, mode="determinate")
        self.button = tk.Button(self, text="Start", command=self.spawnthread)
        self.listbox.pack(padx=10, pady=10)
        self.progressbar.pack(padx=10, pady=10)
        self.button.pack(padx=10, pady=10)

    def spawnthread(self):
        self.button.config(state="disabled")
        self.thread = ThreadedClient(self.queue)
        self.thread.start()
        self.periodiccall()

    def periodiccall(self):
        self.checkqueue()
        if self.thread.is_alive():
            self.after(100, self.periodiccall)
        else:
            self.button.config(state="active")

    def checkqueue(self):
        while self.queue.qsize():
            try:
                msg = self.queue.get(0)
                self.listbox.insert('end', msg)
                self.progressbar.step(25)
            except Queue.Empty:
                pass


class ThreadedClient(threading.Thread):

    def __init__(self, queue):
        threading.Thread.__init__(self)
        self.queue = queue

    def run(self):
        for x in range(1, 5):
            time.sleep(2)
            msg = "Function %s finished..." % x
            self.queue.put(msg)


if __name__ == "__main__":
    app = App()
    app.mainloop()

Since the original example on ActiveState is a bit messy IMO (the ThreadedClient is quite coupled with the GuiPart, and things like controlling the moment to spawn the thread from the GUI are not as straightforward as they could be), I have refactored it and also added a Button to start the new thread.

More Related Contents:

  1. Why does Tkinter image not show up if created in a function?
  2. Tkinter scrollbar for frame
  3. Why is Button parameter “command” executed when declared? [duplicate]
  4. tkinter and time.sleep
  5. How to add placeholder to an Entry in tkinter?
  6. tkinter: binding mousewheel to scrollbar
  7. tkinter: using scrollbars on a canvas
  8. How to redirect print statements to Tkinter text widget
  9. What’s the difference between “update” and “update_idletasks”?
  10. How do I insert a JPEG image into a python Tkinter window?
  11. Mouse Position Python Tkinter
  12. Restricting the value in Tkinter Entry widget
  13. Program freezing during the execution of a function in Tkinter
  14. Tkinter resize background image to window size
  15. How to create a password entry field using Tkinter
  16. Passing data between separately running Python scripts
  17. Tkinter pack method confusion
  18. Adding padding to a tkinter widget only on one side
  19. tkinter PhotoImage doesn’t exist?
  20. How to attach a Scrollbar to a Text widget?
  21. Display message when hovering over something with mouse cursor in Python
  22. Removing Ttk Notebook Tab Dashed Line
  23. How to start threads at the same time in Python [duplicate]
  24. How can I create a simple message box in Python?
  25. Is there a way to make the Tkinter text widget read only?
  26. What is the best way to show data in a table in Tkinter?
  27. Run process with realtime output to a Tkinter GUI
  28. Difference between tkinter and Tkinter
  29. Python – returning from a Tkinter callback
  30. How to change the foreground or background colour of a selected cell in tkinter treeview?

Leave a Comment