If I programmed a window to close after opening a new one why doesn't it close?

Question

I want to make a window that contains a button that opens another new window while closing the initial window. It sounds simple, but I know that I have to be doing something wrong here as it cannot destroy the initial window when it opens the second one. This is the error I get: _tkinter.TclError: can't invoke "destroy" command: application has been destroyed and this is the code sample:

from tkinter import *

def openWindow2():
    win2 = Tk()
    win2.focus()
    win2.geometry("1500x880+200+70")
    win2.title("window2")
    win2.mainloop()

def openWindow1():
    win1 = Tk()
    win1.geometry("700x700+600+150")
    win1.title("window1")
    win1.resizable(False, False)

    titleFrame = Frame(win1)
    titleFrame.pack(side=TOP, pady=25)
    Label(titleFrame, text="Welcome", font=("Helvetica", 30)).pack()

    def openNewWindow():
        openWindow2()
        win1.destroy()

    openButton = Button(win1, text="New Window", font=("Helvetica", 20), command=openNewWindow)
    openButton.pack(pady=5)

    win1.mainloop()
openWindow1()

My intentions are to make a sort of portal/launcher/menu window that lets you open other windows (which are more important than it obviously). Again, I know that I did something wrong but I don't know what to do instead. I tried making the initial or second window Toplevel but that didn't work (as I intended). Currently all that "openNewWindow()" does is open the second window but keeps the initial one open (but unfocused) and gives out the aforementioned error.

So, can anyone tell me why this is happening and how to solve it?

score 3 · Accepted Answer · answered Apr 21 '22 at 19:07

I think you need to change to Toplevel() instead of doubling the Tk() instance and then withdraw() the orignal window instead of destroy() since thats where your mainloop() is. You could also bring back the original window then with deiconify(). check this out.

from tkinter import *

def openWindow2():
    win2 = Toplevel()
    win2.focus()
    win2.geometry("1500x880+200+70")
    win2.title("window2")


def openWindow1():
    win1 = Tk()
    win1.geometry("700x700+600+150")
    win1.title("window1")
    win1.resizable(False, False)

    titleFrame = Frame(win1)
    titleFrame.pack(side=TOP, pady=25)
    Label(titleFrame, text="Welcome", font=("Helvetica", 30)).pack()

    def openNewWindow():
        openWindow2()
        win1.withdraw()

    openButton = Button(win1, text="New Window", font=("Helvetica", 20), command=openNewWindow)
    openButton.pack(pady=5)

    win1.mainloop()
    
openWindow1()

This does work for me, but sometimes it doesn't focus the second window. Why is this? — danielshmaniel, Apr 22 '22 at 07:16
I think the same issue is discussed [here](https://stackoverflow.com/questions/22751100/tkinter-main-window-focus). If that doesn't help, there are some alternative methods for presenting different "frames" to the user in a container utilizing tkraise() to just bring them to the top. This way you don't create another "window" but still take the user to another page. If that sounds like something you want to see let me know and Ill add an example. — Rory, Apr 22 '22 at 14:02

If I programmed a window to close after opening a new one why doesn't it close?

1 Answers1