CODEWITHSUNDEEP
pythontkinter
chew socks
chew socks

Reputation: 1446

Multiple tkinter windows look different when closing and reopening window

I got the following code from a tutorial. I then modified main() so that two windows are created as seperate threads. When I run it, only one window is created. Then when I press the Quit button in that window, a second window appears. In this new window the button has a different look than the first one (a look which I like better) and then if I press either of the two Quit buttons, both windows close and the program exits.

Why does the second window not appear until the first Quit button is pressed, and why does it look different when it does appear?

EDIT: This happens when no threads are used as well, where only one window is created at a time.

EDIT: This is a screenshot of the two windows that are created. The one on the left is created with the program is run, the one on the right is created after clicking the "Quit" button on the first. enter image description here

from Tkinter import Tk, BOTH
from ttk import Frame, Button, Style


class Example(Frame):

    def __init__(self, parent):
        Frame.__init__(self, parent)

        self.parent = parent

        self.initUI()

    def initUI(self):

        self.parent.title("Quit button")
        self.style = Style()
        self.style.theme_use("default")

        self.pack(fill=BOTH, expand=1)

        quitButton = Button(self, text="Quit",
            command=self.quit)
        quitButton.place(x=50, y=50)


from threading import Thread
def main():

    for i in range(2):
        root = Tk()
        root.geometry("250x150+300+300")
        app = Example(root)
        Thread(target=root.mainloop()).start()


if __name__ == '__main__':
    main()

Upvotes: 0

Views: 1847

Answers (1)

Bryan Oakley
Bryan Oakley

Reputation: 385980

You cannot use tkinter this way. Tkinter isn't thread safe, you can only ever access tk widgets and commands except from the thread that created the root window.

As for one window only showing after the other is destroyed even without threading, it's hard to say since you don't show the code. If you're creating more than one instance of Tk, and calling mainloop more than once, that's the problem. Tkinter is designed to work when you create precisely one instance of Tk, and call mainloop precisely once.

If you want more than one window, create a single instance of Tk for the first window, and instances of Toplevel for additional windows.

Upvotes: 1

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