CODEWITHSUNDEEP
pythontkinter
Nadim
Nadim

Reputation: 79

Python tkinter after method causes window to freeze

I've looked around stackoverflow and am pretty sure this isn't a duplicate. I need to poll a queue every 1ms (or as quickly as possible), and this has to run in the same thread as my tkinter window otherwise I can't update my labels from the queue data. (someone correct me if i'm wrong here). Currently my code looks like this:

def newData():
    global gotNewData
    if q.get == 1: #if there is new data
        updateVariables() #call the function to update my labels with said data
        q.queue.clear() #clear the queue
        gotNewData = 0 #no new data to get
        q.put(gotNewData)
        MainPage.after(1, newData)
    else:
        MainPage.after(1, newData)

however when I run this code, my tkinter window freezes instantly. I commented out the line which calls the other function and it still freezes so i'm pretty sure it's this function which is causing the problem. Any help is greatly appreciated.

Upvotes: 0

Views: 223

Answers (1)

Mike - SMT
Mike - SMT

Reputation: 15226

So what I would do if you must have threading is to use a StringVar() in the threaded function instead of having to work with a widget directly.

I feel like 1000 times a second is excessive. Maybe do 10 times a sec instead.

Take a look at this example and let me know if you have any questions.

import tkinter as tk
import threading
root = tk.Tk()

lbl = tk.Label(root, text="UPDATE ME")
lbl.pack()

q_value = tk.StringVar()

q = tk.Entry(root, textvariable=q_value)
q.pack()


def updateVariables(q):
    lbl.config(text=q)


def newData(q):
    if q.get() != '':
        updateVariables(q.get())
        root.after(100, lambda: newData(q))

    else:
        root.after(100, lambda: newData(q))
        print("not anything")


thread = threading.Thread(target=newData, args=(q_value, ))
thread.start()

root.mainloop()

Upvotes: 1

Related Questions