Tkinter method on returning value from TopLevel object to root object-CodePudding

I created a Tkinter app that calls TopLevel objects from another file (for menu bar options).

In my main.py, I have this code:

...
def create():
    funct.createNew()
...

menubar = tk.Menu(window)
#file menu
file = tk.Menu(menubar, tearoff=0)
file.add_command(label='Create new', command=create)
...

And the function being called from functions.py file (I removed the window attributes for simplicity):

def linkToDB():
    global create

    #call the function to create virtual file
    file = sql.generateDB()
    #destroy the createNew window
    create.destroy()

    #debugging purposes
    print("Virtual file:", file)

def createNew():
    #make this global to destroy this window later
    global create

    create = tk.Toplevel()
    ...
    #option 1
    container1 = tk.Frame(create)
    ...
    #generate virtual SQLite file
    btn1 = tk.Button(container1, text="Create", command= lambda: linkToDB())

The above code displays a TopLevel window that will be called by Create button in main.py, which in turn calls a function from sql.py (by that button within TopLevel window) to create temporary SQlite file:

import sqlite3 as sq

#create a virtual sqlite file
def generateDB():
    temp = sq.connect(':memory:')
    temp.execute...
    return temp

My problem is how to return the value of temp from generateDB() to main.py (specifically after destroying the TopLevel window)? I am confused on how to pass this value across the .py files. And whether my approach is viable or not (also looking for suggestions).

P.S. I intentionally destroyed the TopLevel window in linkToDB() since it is guaranteed that my temporary SQlite file will be generated.

CodePudding user response：

You can modify funct.createNew() to return the virtual file to main.py. However you need to make the toplevel window a modal window in order to return the virtual file after the toplevel window is destroyed.

Below is the modified functions.py:

import tkinter as tk
import sql

# pass the toplevel window as an argument instead of using global variable
def linkToDB(create):
    # use an attribute of the toplevel window to store the "virtual db file"
    create.file = sql.generateDB()
    create.destroy()
    print('Virtual file:', create.file)

def createNew():
    create = tk.Toplevel()
    ...
    container1 = tk.Frame(create)
    ...
    btn1 = tk.Button(container1, text='Create', command=lambda: linkToDB(create))
    ...
    # wait for window destroy (works like a modal dialog)
    create.wait_window(create)
    # return the "virtual db file"
    return create.file

Then you can get the virtual db file in main.py:

def create():
    # if you want the "virtual db file" be accessed by other function
    # declare it as global variable
    #global db_file
    db_file = funct.createNew()
    print(db_file)
    ...

...