Using Tkinter widgets on child window

[chewy1418]

Main/Root Window

My issue is in the TopLevel/Secondary Window. In that class, I have a ListBox which I can declare successfully and will appear, but my end goal is to have a button on that screen call a secondary function which will then populate the Listbox with some data from a DB.

Before tackling the database logic I tried to simply just put some data in manually using the below method:

self.Lb1.insert(END, "Entry Value")

But for some reason, it doesn't recognize that command which results in the following error
AttributeError: 'NoneType' object has no attribute 'insert'

Any help would be appreciated :)

from tkinter import *
from tkinter import ttk

class Application(object):
    def __init__(self, master):
        self.topColor = '#f2f2f2'
        self.bottomColor = '#e6e6e6'

        self.master = master

        # Configure our menu
        menu = Menu(self.master)
        self.master.config(menu = menu)

        file = Menu(menu, tearoff = 0)
        file.add_command(label = 'About', command = self.aboutMessage)
        file.add_command(label = 'Exit', command = self.client_exit)
        menu.add_cascade(label = 'File', menu = file)

        edit = Menu(menu, tearoff = 0)
        edit.add_command(label = 'Undo')
        menu.add_cascade(label = 'Edit', menu = edit)

        rules = Menu(menu, tearoff = 0)
        rules.add_command(label = 'Add Table & Function', command = self.addFuncTable)
        rules.add_command(label = 'Search', command = self.search)
        menu.add_cascade(label = 'Rules', menu = rules)

        # ---- Top Frame ---- #
        # Configure frames
        self.top = Frame(master, height = 71, bg = self.topColor)
        self.top.pack(fill = X)
        self.bottom = Frame(master, height = 530, bg = self.bottomColor)
        self.bottom.pack(fill = X)

        self.top_image = PhotoImage(file ='Images/Logo.png')
        Label(self.top, image = self.top_image).place(x = -1, y = -1)

        Label(self.top, text = "H03 & HF9 Mosaic Script Generation Tool", bg = self.topColor, font = ('Calbri', 11)).place(x = 70, y = 5)
        Label(self.top, text = 'Use the below entry boxes to fill in the necessary information about your ITR', bg = self.topColor).place(x = 70, y = 30)
        Label(self.top, text = 'This will include your Version Number(s), GUID, etc', bg = self.topColor).place(x = 70, y = 48)

        # ---- Bottom Frame ---- #

        # Define var's for each of our fields so we can get the value
        self.entry_appendixPath = StringVar()
        self.entry_rateSheetPath = StringVar()


        Label(self.bottom, text = 'File Path for Appendix:', bg = self.bottomColor).place(x = 4, y = 20)
        self.appendix = ttk.Entry(self.bottom, width = 30, textvariable = self.entry_appendixPath).place(x = 7, y = 40)

        Label(self.bottom, text = "File Path for Rate Sheet:", bg = self.bottomColor).place(x = 250, y = 20)
        self.rateSheet = ttk.Entry(self.bottom, width = 30, textvariable = self.entry_rateSheetPath).place(x = 253, y = 40)

        Label(self.bottom, text = "Script Author:", bg = self.bottomColor).place(x = 4, y = 80)
        ttk.Entry(self.bottom).place(x = 7, y = 100)

        Label(self.bottom, text = "GUID Identifier:", bg = self.bottomColor).place(x = 170, y = 80)
        ttk.Entry(self.bottom).place(x = 173, y = 100)

        self.StateCodeVal = StringVar()
        Label(self.bottom, text = "State Code:", bg = self.bottomColor).place(x = 350, y = 80)
        ttk.Combobox(self.bottom, textvariable = self.StateCodeVal, width = 10, values = [
            "PA", "AK", "AZ", "AR", "CA", "CO", "CT", "DC", "DE", "FL", "GA",
            "HI", "ID", "IL", "IN", "IA", "KS", "KY", "LA", "ME", "MD", "MA",
            "MI", "MN", "MS", "MO", "MT", "NE", "NV", "NH", "NJ", "NM", "NY",
            "NC", "ND", "OH", "OK", "OR", "PA", "RI", "SC", "SD", "TN", "TX",
            "UT", "VT", "VA", "WA", "WV", "WI", "WY"
        ]).place(x = 353, y = 100)

        Label(self.bottom, text = "Current Version", bg = self.bottomColor).place(x = 4, y = 135)
        ttk.Entry(self.bottom).place(x = 7, y = 155)

        Label(self.bottom, text = "New Version:", bg = self.bottomColor).place(x = 170, y = 135)
        ttk.Entry(self.bottom).place(x = 173, y = 155)

        Label(self.bottom, text = "UW Company:", bg = self.bottomColor).place(x = 350, y = 135)
        ttk.Entry(self.bottom, width = 10).place(x = 353, y = 155)

        Button(self.bottom, text="Lookup Version", command=self.lookupOldVersion).place(x=6, y=180)

        # Not an easy way to execute a stored proc in python with OUTPUT params
        # Button(self.bottom, text="Generate").place(x = 173, y = 180)

        Label(self.bottom, text="Above button call requires that both State Code and Apex Flag are valued!", bg = self.bottomColor, fg="Red").place(x = 4, y = 210)

        self.ApexCheck = StringVar()
        Label(self.bottom, text="Apex Flag ( 1 -> is Apex, 0 -> Legacy):",
              bg=self.bottomColor).place(x = 4, y = 250)
        ttk.Combobox(self.bottom,  textvariable=self.ApexCheck, width = 10, values = [
           1, 2
        ]).place(x = 4, y = 272)

        Label(self.bottom, text = "Do we need to create new procedure(s) or table(s) for this ITR?", bg = self.bottomColor).place(x = 4, y = 310)

        # Set style for ttk.RadioButton since bg= is not supported
        s = ttk.Style()
        s.configure(
            'myStyle.TRadioButton',
            background = self.bottomColor
        )

        self.newCheck = IntVar()
        ttk.Radiobutton(self.bottom, text = "Yes", variable = self.newCheck, value = 1).place(x = 5, y = 335)
        ttk.Radiobutton(self.bottom, text = "No", variable = self.newCheck, value = 0).place(x = 5, y = 360)

        # Radiobutton(self.bottom, text = "Yes", bg = self.bottomColor, variable = newCheck, value = 1).place(x = 4, y = 270)
        # Radiobutton(self.bottom, text = "No", bg = self.bottomColor, variable = newCheck, value = 0).place(x = 4, y = 290)

        # Checkbutton(self.bottom, bg = self.bottomColor, text = "Yes", variable = newCheck).place(x = 4, y = 270)

        Button(self.bottom, text = 'Submit', fg = 'white', bg = '#00802b', command = self.getEntries).place(x = 4 , y = 400)


    def search(self):
        S = Search.Search()


def main():
    root = Tk()
    app = Application(root)
    root.title('Main Window')
    root.geometry('500x600')
    root.resizable(False, False)
    root.mainloop()

if __name__ == '__main__':
    main()

Second Window

# Tkinter modules
from tkinter import *
from tkinter import ttk
from tkinter import messagebox

class Search(Toplevel):
    def __init__(self):
        Toplevel.__init__(self)

        self.geometry('500x500')
        self.title('Search')
        self.resizable(False, False)

        self.topColor = '#f2f2f2'
        self.bottomColor = '#e6e6e6'

        # Configure frames
        self.top = Frame(self, height=71, bg=self.topColor)
        self.top.pack(fill=X)
        self.bottom = Frame(self, height=430, bg=self.bottomColor)
        self.bottom.pack(fill=X)

        self.top_image = PhotoImage(file='Images/Logo.png')
        Label(self.top, image=self.top_image).place(x=-1, y=-1)

        Label(self.bottom, text="Current Version:", bg=self.bottomColor).place(x = 5, y = 15)
        ttk.Entry(self.bottom).place(x = 7, y = 35)

        Label(self.bottom, text="New Version:", bg=self.bottomColor).place(x = 150, y = 15)
        ttk.Entry(self.bottom).place(x = 153, y = 35)

        Button(self.bottom, text = "Get Existing Rules ..").place(x = 5, y = 65)

        self.Lb1 = Listbox(self.bottom).place(x = 5, y = 140)


    def updateListBox(self):
        pass