tkinter (unsure of my error possibly due to .destroy())

Question

from Tkinter import *
import random
menu = Tk()
subpage = Tk()
entry_values = []
population_values = []
startUpPage = Tk()

def main_menu(window):

    window.destroy()
    global menu 
    menu = Tk()
    frame1 = Frame(menu)
    menu.resizable(width=FALSE, height=FALSE)
    button0 = Button(menu, text="Set Generation Zero Values", command=sub_menu(menu))
    button1 = Button(menu, text="Display Generation Zero Values")
    button2 = Button(menu, text="Run Model")
    button3 = Button(menu, text="Export Data")
    button4 = Button(menu, text="Exit Program", command=menu.destroy)

    button0.grid(row=0, column=0, sticky=W)
    button1.grid(row=2, column=0, sticky=W)
    button2.grid(row=3, column=0, sticky=W)
    button3.grid(row=4, column=0, sticky=W)
    button4.grid(row=5, column=0, sticky=W)

    menu.mainloop()

def sub_menu(window):
    global subpage
    window.destroy()
    subpage = Tk()
    subpage.resizable(width=FALSE, height=FALSE)

    #defining sub page items
    button5 = Button(subpage, text="Save Generation Data",command = main_menu(subpage))



    juveniles_label0 = Label(subpage,text="Juveniles")
    adults_label1 = Label(subpage,text="Adults")
    seniles_label2 = Label(subpage,text="Seniles")
    population_label3 = Label(subpage,text="Popultation")
    survival_rate_label4 = Label(subpage,text="Survival Rate (Between 0 and 1)")

    entry0 = Entry(subpage)
    entry1 = Entry(subpage)
    entry2 = Entry(subpage)
    entry3 = Entry(subpage)
    entry4 = Entry(subpage)
    entry5 = Entry(subpage)

    button4.grid(row=1, column= 6, sticky=E)

    juveniles_label0.grid(row=0, column=1) 
    adults_label1.grid(row=0, column=2)
    seniles_label2.grid(row=0, column=3)
    population_label3.grid(row=1, column=0)
    survival_rate_label4.grid(row=2, column=0)

    entry0.grid(row=1, column=1)
    entry1.grid(row=1, column=2)
    entry2.grid(row=1, column=3)
    entry3.grid(row=2, column=1)
    entry4.grid(row=2, column=2)
    entry5.grid(row=2, column=3)
    #add entry 6 7 8 
    subpage.mainloop()

main_menu(subpage)
main_menu(startUpPage)

I'm very new to coding and stackoverflow. I am trying to create a GUI that has a main page which will be opened first and a sub page which will be opened by clicking a button which will be stored in the main page. my issue is that I have no clue why it isn't opening my main page. my thought is that it is something to do with the .destroy() or something similar. any help would be much appreciated.

Answer 1

heres some code that does what you want.. make a window, destroy it when button is clicked and then make a new window...

from Tkinter import *
import random


def main_menu():
    global root
    root = Tk()
    b = Button(root,text='our text button',command = next_page)
    b.pack()

def next_page():
    global root,parent
    parent = Tk()
    root.destroy()
    new_b = Button(parent,text = 'new Button',command=print_something)
    new_b.pack()

def print_something():
    print('clicked')


main_menu()
root.mainloop()
parent.mainloop()

ps. ive done this in python3 so keep that in mind though it wouldnt be a problem in my opinion

Answer 2

As a general rule, you should create exactly one instance of Tk for the life of your program. That is how Tkinter is designed to be used. You can break this rule when you understand the reasoning behind it, though there are very few good reasons to break the rule.

The simplest solution is to implement your main menu and your sub menu as frames, which you've already done. To switch between them you can simply destroy one and (re)create the other, or create them all ahead of time and then remove one and show the other.

For example, the following example shows how you would create them ahead of time and simply swap them out. The key is that each function needs to return the frame, which is saved in a dictionary. The dictionary is used to map symbolic names (eg: "main", "sub", etc) to the actual frames.

def main_menu(root):
    menu = Frame(root)
    button0 = Button(menu, text="Set Generation Zero Values",
                     command=lambda: switch_page("sub"))
    ...
    return menu

def sub_menu(root):
    subpage = Frame(root)
    button5 = Button(subpage, text="Save Generation Data",
                     command = lambda: switch_page("main"))
    ...
    return subpage

def switch_page(page_name):
    slaves = root.pack_slaves()
    if slaves:
        # this assumes there is only one slave in the master
        slaves[0].pack_forget()
    pages[page_name].pack(fill="both", expand=True)

root = Tk()
pages = {
    "main": main_menu(root),
    "sub": sub_menu(root),
    ...
}

switch_page("main")
root.mainloop()

For a more complex object-oriented approach see Switch between two frames in tkinter