GUI To-Do List App in Python Tkinter

Introduction

Hello friends, today we will create GUI To-Do List App in Python Tkinter. Python tkinter is a standard Python interface to the Tk GUI toolkit. The design of this system is rather straightforward, so the user will encounter no issues when working on it.

We will be using the tkinter library for GUI and SQLite for the database. After the 2.5 version of Python, both libraries are builtin with python.

GUI To-Do List App in Python Tkinter: Project Overview

Project Name:	GUI To-Do List App in Python Tkinter
Abstract	It’s a GUI-based project used with the tkinter module to organize all the elements that work under the to-do list app in python.
Language/s Used:	Python
IDE	PyCharm and Thonny(recommended for beginners)
Python version (Recommended):	Python 3.x
Database:	SQLite
Type:	Desktop Application
Recommended for	Beginner and intermediate Python programmers

Complete code to create GUI To-Do List App in Python Tkinter:

# importing the required modules                            
from tkinter import *
# importing the messagebox module from the tkinter library  
from tkinter import messagebox
# importing the sqlite3 module as sql  
import sqlite3 as sql
 

# defining the function to add tasks to the list  
def add_task():  
    # getting the string from the entry field  
    task_string = task_field.get()  
    # checking whether the string is empty or not  
    if len(task_string) == 0:  
        # displaying a message box with 'Empty Field' message  
        messagebox.showinfo('Error', 'Field is Empty.')  
    else:  
        # adding the string to the tasks list  
        tasks.append(task_string)  
        # using the execute() method to execute a SQL statement  
        the_cursor.execute('insert into tasks values (?)', (task_string ,))  
        # calling the function to update the list  
        list_update()  
        # deleting the entry in the entry field  
        task_field.delete(0, 'end')  
  
# defining the function to update the list  
def list_update():  
    # calling the function to clear the list  
    clear_list()  
    # iterating through the strings in the list  
    for task in tasks:  
        # using the insert() method to insert the tasks in the list box  
        task_listbox.insert('end', task)  
  
# defining the function to delete a task from the list  
def delete_task():  
    # using the try-except method  
    try:  
        # getting the selected entry from the list box  
        the_value = task_listbox.get(task_listbox.curselection())  
        # checking if the stored value is present in the tasks list  
        if the_value in tasks:  
            # removing the task from the list  
            tasks.remove(the_value)  
            # calling the function to update the list  
            list_update()  
            # using the execute() method to execute a SQL statement  
            the_cursor.execute('delete from tasks where title = ?', (the_value,))  
    except:  
        # displaying the message box with 'No Item Selected' message for an exception  
        messagebox.showinfo('Error', 'No Task Selected. Cannot Delete.')        
  
# function to delete all tasks from the list  
def delete_all_tasks():  
    # displaying a message box to ask user for confirmation  
    message_box = messagebox.askyesno('Delete All', 'Are you sure?')  
    # if the value turns to be True  
    if message_box == True:  
        # using while loop to iterate through the tasks list until it's empty   
        while(len(tasks) != 0):  
            # using the pop() method to pop out the elements from the list  
            tasks.pop()  
        # using the execute() method to execute a SQL statement  
        the_cursor.execute('delete from tasks')  
        # calling the function to update the list  
        list_update()  
  
# function to clear the list  
def clear_list():  
    # using the delete method to delete all entries from the list box  
    task_listbox.delete(0, 'end')  
  
# function to close the application  
def close():  
    # printing the elements from the tasks list  
    print(tasks)  
    # using the destroy() method to close the application  
    guiWindow.destroy()  
  
# function to retrieve data from the database  
def retrieve_database():  
    # using the while loop to iterate through the elements in the tasks list  
    while(len(tasks) != 0):  
        # using the pop() method to pop out the elements from the list  
        tasks.pop()  
    # iterating through the rows in the database table  
    for row in the_cursor.execute('select title from tasks'):  
        # using the append() method to insert the titles from the table in the list  
        tasks.append(row[0])  
  
# main function  
if __name__ == "__main__":  
    # creating an object of the Tk() class  
    guiWindow = Tk()  
    # setting the title of the window  
    guiWindow.title("To-Do List ")  
    # setting the geometry of the window  
    guiWindow.geometry("665x400+550+250")  
    # disabling the resizable option  
    guiWindow.resizable(0, 0)  
    # setting the background color to #B5E5CF 
    guiWindow.configure(bg = "#B5E5CF")  
  
    # using the connect() method to connect to the database  
    the_connection = sql.connect('listOfTasks.db')  
    # creating the cursor object of the cursor class  
    the_cursor = the_connection.cursor()  
    # using the execute() method to execute a SQL statement  
    the_cursor.execute('create table if not exists tasks (title text)')  
  
    # defining an empty list  
    tasks = []  
      
    # defining frames using the tk.Frame() widget  
    functions_frame = Frame(guiWindow, bg = "black") 
  
    # using the pack() method to place the frames in the application  
    functions_frame.pack(side = "top", expand = True, fill = "both")  
 
      

    # defining another label using the Label() widget  
    task_label = Label( functions_frame,text = "Enter the Task:",  
        font = ("arial", "14", "bold"),  
        background = "black", 
        foreground="white"
    )  
    # using the place() method to place the label in the application  
    task_label.place(x = 20, y = 30)  
      
    # defining an entry field using the Entry() widget  
    task_field = Entry(  
        functions_frame,  
        font = ("Arial", "14"),  
        width = 42,  
        foreground="black",
        background = "white",  
    )  
    # using the place() method to place the entry field in the application  
    task_field.place(x = 180, y = 30)  
  
    # adding buttons to the application using the Button() widget  
    add_button =Button(  
        functions_frame,  
        text = "Add Task",  
        width = 15,
        bg='#D4AC0D',font=("arial", "14", "bold"),
        command = add_task,
        
    )  
    del_button = Button(  
        functions_frame,  
        text = "Delete Task",  
        width = 15,
        bg='#D4AC0D', font=("arial", "14", "bold"),
        command = delete_task,  
    )  
    del_all_button = Button(  
        functions_frame,  
        text = "Delete All Tasks",  
        width = 15,
        font=("arial", "14", "bold"),
        bg='#D4AC0D',
        command = delete_all_tasks  
    )  
    exit_button = Button(  
        functions_frame,  
        text = "Exit",  
        width = 52,
        bg='#D4AC0D',  font=("arial", "14", "bold"),
        command = close  
    )  
    # using the place() method to set the position of the buttons in the application  
    add_button.place(x = 18, y = 80,)  
    del_button.place(x = 240, y = 80)  
    del_all_button.place(x = 460, y = 80)  
    exit_button.place(x = 17, y = 330)  
  
    # defining a list box using the tk.Listbox() widget  
    task_listbox = Listbox(  
        functions_frame,  
        width = 57,  
        height = 7,  
        font="bold",
        selectmode = 'SINGLE',  
        background = "WHITE",
        foreground="BLACK",    
        selectbackground = "#D4AC0D",  
        selectforeground="BLACK"
    )  
    # using the place() method to place the list box in the application  
    task_listbox.place(x = 17, y = 140)  
  
    # calling some functions  
    retrieve_database()  
    list_update()  
    # using the mainloop() method to run the application  
    guiWindow.mainloop()  
    # establishing the connection with database  
    the_connection.commit()  
    the_cursor.close()

Now, let’s understand our GUI To-Do List App in Python Tkinter step by step by breaking code into sub-parts.

Step.1: Import libraries for To-Do List App

# importing the required modules                            
from tkinter import *
# importing the messagebox module from the tkinter library  
from tkinter import messagebox
# importing the sqlite3 module as sql  
import sqlite3 as sql

In the above code, we imported the tkinter module as tk. The Tkinter messagebox was then imported. Finally, the sqlite3 module was loaded as sql.

Step.2: Creating function for buttons:

# defining the function to add tasks to the list  
def add_task():  
    # getting the string from the entry field  
    task_string = task_field.get()  
    # checking whether the string is empty or not  
    if len(task_string) == 0:  
        # displaying a message box with 'Empty Field' message  
        messagebox.showinfo('Error', 'Field is Empty.')  
    else:  
        # adding the string to the tasks list  
        tasks.append(task_string)  
        # using the execute() method to execute a SQL statement  
        the_cursor.execute('insert into tasks values (?)', (task_string ,))  
        # calling the function to update the list  
        list_update()  
        # deleting the entry in the entry field  
        task_field.delete(0, 'end')

The above code determines if the string is inserted or not and stores it in the database of the To-Do List App.

# defining the function to update the list  
def list_update():  
    # calling the function to clear the list  
    clear_list()  
    # iterating through the strings in the list  
    for task in tasks:  
        # using the insert() method to insert the tasks in the list box  
        task_listbox.insert('end', task)  
 
# defining the function to delete a task from the list  
def delete_task():  
    # using the try-except method  
    try:  
        # getting the selected entry from the list box  
        the_value = task_listbox.get(task_listbox.curselection())  
        # checking if the stored value is present in the tasks list  
        if the_value in tasks:  
            # removing the task from the list  
            tasks.remove(the_value)  
            # calling the function to update the list  
            list_update()  
            # using the execute() method to execute a SQL statement  
            the_cursor.execute('delete from tasks where title = ?', (the_value,))  
    except:  
        # displaying the message box with 'No Item Selected' message for an exception  
        messagebox.showinfo('Error', 'No Task Selected. Cannot Delete.')
 
# function to delete all tasks from the list  
def delete_all_tasks():  
    # displaying a message box to ask user for confirmation  
    message_box = messagebox.askyesno('Delete All', 'Are you sure?')  
    # if the value turns to be True  
    if message_box == True:  
        # using while loop to iterate through the tasks list until it's empty  
        while(len(tasks) != 0):  
            # using the pop() method to pop out the elements from the list  
            tasks.pop()  
        # using the execute() method to execute a SQL statement  
        the_cursor.execute('delete from tasks')  
        # calling the function to update the list  
        list_update()

# function to clear the list  
def clear_list():  
    # using the delete method to delete all entries from the list box  
    task_listbox.delete(0, 'end')

# function to close the application  
def close():  
    # printing the elements from the tasks list  
    print(tasks)  
    # using the destroy() method to close the application  
    guiWindow.destroy()

# function to retrieve data from the database  
def retrieve_database():  
    # using the while loop to iterate through the elements in the tasks list  
    while(len(tasks) != 0):  
        # using the pop() method to pop out the elements from the list  
        tasks.pop()  
    # iterating through the rows in the database table  
    for row in the_cursor.execute('select title from tasks'):  
        # using the append() method to insert the titles from the table in the list  
        tasks.append(row[0])

Step.3: Creating GUI of To-Do List App

# main function  
if __name__ == "__main__":  
    # creating an object of the Tk() class  
    guiWindow = Tk()  
    # setting the title of the window  
    guiWindow.title("To-Do List ")  
    # setting the geometry of the window  
    guiWindow.geometry("665x400+550+250")  
    # disabling the resizable option  
    guiWindow.resizable(0, 0)  
    # setting the background color to #B5E5CF
    guiWindow.configure(bg = "#B5E5CF")  
 
    # using the connect() method to connect to the database  
    the_connection = sql.connect('listOfTasks.db')  
    # creating the cursor object of the cursor class  
    the_cursor = the_connection.cursor()  
    # using the execute() method to execute a SQL statement  
    the_cursor.execute('create table if not exists tasks (title text)')  
 
    # defining an empty list  
    tasks = []  
     
    # defining frames using the tk.Frame() widget  
    functions_frame = Frame(guiWindow, bg = "black")
 
    # using the pack() method to place the frames in the application  
    functions_frame.pack(side = "top", expand = True, fill = "both")

Step.4: Create a task entry widget and design the button

    # defining another label using the Label() widget  
    task_label = Label( functions_frame,text = "Enter the Task:",  
        font = ("arial", "14", "bold"),  
        background = "black",
        foreground="white"
    )  
    # using the place() method to place the label in the application  
    task_label.place(x = 20, y = 30)  
     
    # defining an entry field using the Entry() widget  
    task_field = Entry(  
        functions_frame,  
        font = ("Arial", "14"),  
        width = 42,  
        foreground="black",
        background = "white",  
    )  
    # using the place() method to place the entry field in the application  
    task_field.place(x = 180, y = 30)  
 
    # adding buttons to the application using the Button() widget  
    add_button =Button(  
        functions_frame,  
        text = "Add Task",  
        width = 15,
        bg='#D4AC0D',font=("arial", "14", "bold"),
        command = add_task,
       
    )  
    del_button = Button(  
        functions_frame,  
        text = "Delete Task",  
        width = 15,
        bg='#D4AC0D', font=("arial", "14", "bold"),
        command = delete_task,  
    )  
    del_all_button = Button(  
        functions_frame,  
        text = "Delete All Tasks",  
        width = 15,
        font=("arial", "14", "bold"),
        bg='#D4AC0D',
        command = delete_all_tasks  
    )  
    exit_button = Button(  
        functions_frame,  
        text = "Exit",  
        width = 52,
        bg='#D4AC0D',  font=("arial", "14", "bold"),
        command = close  
    )  
    # using the place() method to set the position of the buttons in the application  
    add_button.place(x = 18, y = 80,)  
    del_button.place(x = 240, y = 80)  
    del_all_button.place(x = 460, y = 80)  
    exit_button.place(x = 17, y = 330)

Step.5: Creating list box layout and updating the database

    # defining a list box using the tk.Listbox() widget  
    task_listbox = Listbox(  
        functions_frame,  
        width = 57,  
        height = 7,  
        font="bold",
        selectmode = 'SINGLE',  
        background = "WHITE",
        foreground="BLACK",    
        selectbackground = "#D4AC0D",  
        selectforeground="BLACK"
    )  
    # using the place() method to place the list box in the application  
    task_listbox.place(x = 17, y = 140)  
 
    # calling some functions  
    retrieve_database()  
    list_update()  
    # using the mainloop() method to run the application  
    guiWindow.mainloop()  
    # establishing the connection with database  
    the_connection.commit()  
    the_cursor.close()

The Listbox widget is used to show the user the list of items. The location of the listbox is also specified. Python calls window.mainloop() to start the Tkinter event loop for To-Do List App.

Output for GUI To-Do List App in Python Tkinter:

Output of GUI To-Do List App in Python Tkinter

We successfully created the GUI To-Do List App in Python Tkinter. This project is suitable for students who wish to learn Python programming since it has a Graphical User Interface (GUI) and a user-friendly interface. This project on To-Do List App is easy to understand and run, and it is exclusively for educational purposes.

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