How to make code run after a tkinter window pop up

Question

My code should create a window and then count from 1 to 10 but, it
makes a window and only counts from 1 to 10 when you close the window. how do I make it count when the window pops up, not when it closes?

from tkinter import Tk, mainloop
import time
I = 1
window = Tk()
window.title("Game")
window.configure(width=500, height=300)
window.configure(bg='blue')
window.geometry("+" + str(I * 5) + "+0")
window.mainloop()
while I < 10:
    print(I)
    print("Hi")
    I += 1
    time.sleep(0.2)

Asked By: Human De dios

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Source

Answer 1

The while loop in your code only runs after the window.mainloop() (after it has ended).

This code seems to work:

from tkinter import Tk
I = 1
window = Tk()
window.title("Game")
window.configure(width=500, height=300)
window.configure(bg='blue')
window.geometry("+" + str(I * 5) + "+0")
def loop():
    global I
    print(I)
    print("Hi")
    I += 1
    window.after(200, loop)
loop()
window.mainloop()

The window.after() method is used to run some kind of loops even when the mainloop is running.

Answered By: Swagrim

Answer 2

What mainloop does is start using the main thread for GUI events and nothing else; that’s why your counting code starts only after closing the window. If you want to execute code while the GUI is running, you can use the after method:

from tkinter import Tk, mainloop
import time

I = 1
# Wrap the code in a standalone method
def count():
    # In order to access a global variable from a method
    global I
    while I < 10:
        print(I)
        print("Hi")
        I += 1
        time.sleep(0.2)

window = Tk()
window.title("Game")
window.configure(width=500, height=300)
window.configure(bg='blue')
window.geometry("+" + str(I * 5) + "+0")
# In order to have the window rendered already
window.update()
# Execute code on the main thread
window.after(0, count)
window.mainloop()

Answered By: comodoro

How to make code run after a tkinter window pop up

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