[SOLVED] Text field in Tkinter returns not defined (Python)

IamtheSenate · 05-08-2022, 12:00 PM

I'm using the Python Tkinter code below as a 'simple' demo. I'm still very new to Tkinter but I can't figure this out after several hours:

Code:

import tkinter as tk

login = tk.Tk()
login.geometry('300x150')
login.title('Login')

# login_screen entry fields
utext = tk.StringVar()
ptext = tk.StringVar()

# diary entry fields
date = tk.StringVar()
subject = tk.StringVar()

def login_process():
    if utext.get() == "u" and ptext.get() == "p":
        login.destroy()
        diary()
    
    else:
        tk.Label(login, text="Username or password wrong").pack()

def save():
    print(journal_entry.get("1.0","end"))

def login_screen():
    # username label and entry
    username_label = tk.Label(text="Enter username:").pack()
    username_entry = tk.Entry(textvariable=utext, fg="green", bg="black", width=15).pack()

    # password label and entry
    password_label = tk.Label(text="Enter password:").pack()
    password_entry = tk.Entry(textvariable=ptext, fg="green", bg="black", width=15, show="*").pack()

    #submit button
    submit = tk.Button(text="Submit", width=10, height=1, bg="red", fg="white", command=login_process).pack()

    login.mainloop()

def diary():
    journal = tk.Tk()
    journal.geometry('700x400')
    journal.title('My Journal')

    # journal date
    date_label = tk.Label(text="Today's date (DD.MM.YY):").pack()
    date_entry = tk.Entry(textvariable=date, fg="black", bg="white", width=10).pack()

    # journal subject
    subject_label = tk.Label(text="Subject:").pack()
    subject_entry = tk.Entry(textvariable=subject, fg="black", bg="white", width=40).pack()

    # journal entry
    journal_label = tk.Label(text="Journal entry:").pack()
    journal_entry = tk.Text(journal, height=10, width=40)
    journal_entry.pack()

    # save button
    submit = tk.Button(text="Submit", width=10, height=1, bg="red", fg="white", command=save).pack()

    journal.mainloop()

login_screen()

The purpose is to log in, create a journal entry and then save as a text file. However the text field variable name is always returned as 'undefined':

Code:

Exception in Tkinter callback
Traceback (most recent call last):
  File "/usr/lib/python3.9/tkinter/__init__.py", line 1892, in __call__
    return self.func(*args)
  File "/home/aaron/Desktop/scripts_for_tuesday/test.py", line 24, in save
    print(journal_entry.get("1.0","end"))
NameError: name 'journal_entry' is not defined

teckk · 05-08-2022, 03:15 PM

The way you have that written, you could solve that with

Line 54

Code:

# journal entry
journal_label = tk.Label(text="Journal entry:").pack()
global journal_entry
journal_entry = tk.Text(journal, height=10, width=40)
journal_entry.pack()

Or return something from the function.

Code:

def diary():

Another words. Function def save(): is not aware of anything in Function def diary(): unless you share it.

Edit:
And I did run that. And look for error.
https://0x0.st/omcr.png
https://0x0.st/omcs.png

teckk · 05-08-2022, 04:49 PM

Code:

#!/usr/bin/python

#Share variables between functions demo

def drawLine(length, label=''):
    line = '-' * length
    if label:
        line += ' ' + label
    print(line)

def interval(num):
    if num > 0:
        interval(num - 1)
        drawLine(num)
        interval(num - 1)

def drawRuler(inches, length):
    drawLine(length, '0')
    for i in range(1, 1 + inches):
        interval(length - 1)
        drawLine(length, str(i))

drawRuler(5, 3)

IamtheSenate · 05-09-2022, 03:02 AM

Quote:

Originally Posted by teckk

The way you have that written, you could solve that with

Line 54

Code:

# journal entry
journal_label = tk.Label(text="Journal entry:").pack()
global journal_entry
journal_entry = tk.Text(journal, height=10, width=40)
journal_entry.pack()

Or return something from the function.

Code:

def diary():

Another words. Function def save(): is not aware of anything in Function def diary(): unless you share it.

Edit:
And I did run that. And look for error.
https://0x0.st/omcr.png
https://0x0.st/omcs.png

Thank you very much, after all that debugging and decomposition of the program it was just an out of scope variable!