How to make a TODO App for skratch with Python and tkinter

This is a fully functional app to make a to-do list with Python and tkinter. You will understand how does a listbox with tkinter works to do all the fundamental things you need, through a really working app, a classic todo app.

This code will show you:

how to make a basic window
how to add widgets like
- labels
- listbox
- entry
how to bind action to the widgets to
- add items to listbox through entry with Enter
- save list on external file with Control + s
- delete items with double button
how to use tk.Variable
how to use tk.StringVar
how to save the listbox content
hot to load the saved data when you restart the app

The code to make a TO DO app with Python and tkinter’s Listbox

import tkinter as tk
import os
 
 
def add(event):
    "add item to listbox with entry when Return is pressed"
 
    lst.insert(tk.END, entry.get())
    v.set("")
    save("")
 
 
def delete(event):
    "deletes items in listbox with double click on item"
    lst.delete(tk.ANCHOR)
    save("")
 
 
def save(event):
    "saves memos in listbox"
    with open("data.txt", "w") as file:
        file.write("\n".join(lv.get()))
    label["text"] = "Data saved"
 
 
def getdata():
    "grab saved data"
    if "data.txt" in os.listdir():
        with open("data.txt") as file:
            for line in file:
                lst.insert(tk.END, line.strip())
 
 
root = tk.Tk()
root.geometry("400x400+500+10")
root.title("To do list in Python")
lab1 = tk.Label(
    root, text="Enter to add items, \nSelect to delete Items, ctr+s to save")
lab1.pack()
 
v = tk.StringVar()
entry = tk.Entry(root, textvariable=v)
entry.pack()
 
 
lv = tk.Variable()
lst = tk.Listbox(root, listvariable=lv)
lst.pack()
lst.bind("<Double-Button>", delete)
 
entry.bind("<Return>", add)
root.bind("<Control-s>", save)
 
label = tk.Label(root)
label.pack()
 
# Grab the saved data
getdata()
 
root.mainloop()