To Do list GUI app using Tkinter in Python (Pie chart included) – Full code

In this Tkinter tutorial, I am going to share you with full Python code of a Tkinter GUI application which is To do app.

I am considering  it as the best To do app that you will find on the internet built using Python.

The reason is, here I have made an easy-to-understand interface for the users as well as added cool features like:

1. Pie chart to show the percentage of task completion
2. Counting system to count total tasks, remaining tasks and completed tasks in a single place.
3. Used scroll bar just to make the interface more charming and smooth to use when it comes to a large number of tasks in your app.
4. One click load and save data option so that you never lose a single data.

Here is our final output:

The two icons that we have used can be downloaded from here: todo app icons.zip

Extract the zip files once downloaded and keep those in the same directory where your .py file is residing.

Python code to build Tkinter application.

import tkinter as tk
from tkinter import messagebox
from PIL import Image, ImageTk
import matplotlib.pyplot as plt
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

# Create the main window
newWindow = tk.Tk()
newWindow.title("To-Do List by CodeSpeedy")

# Set the window size
newWindow.geometry("590x800+270+200")  # Increased height to accommodate pie chart

# Set the background color
newWindow.configure(bg="#0d1525")

# Function to resize images
def resize_image(image_path, size, background_color=(13, 21, 37)):
    with Image.open(image_path) as img:
        # Create a new image with a background color
        bg = Image.new('RGBA', img.size, background_color + (255,))
        bg.paste(img, (0, 0), img)  # Paste the original image on top of the background
        img = bg.resize(size, Image.LANCZOS)  # Resize the image with the background color
        return ImageTk.PhotoImage(img)

# Resize the icons with NECESSARY background
done_icon = resize_image("done_icon.png", (20, 20), background_color=(13, 21, 37))
delete_icon = resize_image("delete_icon.png", (20, 20), background_color=(13, 21, 37))

# Function to mark a task as done
def mark_as_done(task_label, done_button):
    task_label.config(fg="gray", font=("Helvetica", 18, "overstrike"))
    done_button.config(image=done_icon, state=tk.DISABLED, disabledforeground="green")
    update_task_count()

# Function to delete a specific task and update serial numbers
def delete_task(task_frame):
    task_frame.destroy()
    update_serial_numbers()
    update_task_count()

# Function to add a task
def add_task(task=None):
    if not task:
        task = task_entry.get()
    if task:
        task_frame = tk.Frame(task_container, bg="#1d2332", pady=5)
        task_number = len(task_container.winfo_children()) + 1
        task_label = tk.Label(task_frame, text=f"{task_number}. {task}", bg="#1d2332", fg="#ffffff", font=("Helvetica", 18))
        task_label.pack(side=tk.LEFT, padx=10)

        done_button = tk.Button(task_frame, image=done_icon, command=lambda: mark_as_done(task_label, done_button), bg="#add8e6", fg="#1cbd52", font=("Helvetica", 12))
        done_button.pack(side=tk.RIGHT, padx=5)

        delete_button = tk.Button(task_frame, image=delete_icon, command=lambda: delete_task(task_frame), bg="#ff6347", fg="#e0194b", font=("Helvetica", 12))
        delete_button.pack(side=tk.RIGHT, padx=5)

        task_frame.pack(fill=tk.X, pady=5)
        task_entry.delete(0, tk.END)
        update_serial_numbers()
        update_task_count()
        canvas.update_idletasks()  # Update the canvas to reflect the new task
        canvas.configure(scrollregion=canvas.bbox("all"))  # Update the scroll region

# Function to update the serial numbers of the tasks
def update_serial_numbers():
    for index, task_frame in enumerate(task_container.winfo_children()):
        task_label = task_frame.winfo_children()[0]
        task_text = task_label.cget("text")
        if ". " in task_text:
            task_text = task_text.split(". ", 1)[1]
        task_label.config(text=f"{index + 1}. {task_text}")

# Function to delete all tasks
def delete_all_tasks():
    for widget in task_container.winfo_children():
        widget.destroy()
    update_task_count()

# Function to update task count labels
def update_task_count():
    total_tasks = len(task_container.winfo_children())
    done_tasks = sum(1 for task_frame in task_container.winfo_children() if "overstrike" in task_frame.winfo_children()[0].cget("font"))
    remaining_tasks = total_tasks - done_tasks

    total_tasks_label.config(text=f"Total Tasks: {total_tasks}")
    remaining_tasks_label.config(text=f"Remaining Tasks: {remaining_tasks}")
    done_tasks_label.config(text=f"Completed Tasks: {done_tasks}")
    update_pie_chart(total_tasks, remaining_tasks, done_tasks)

# Function to update the pie chart
def update_pie_chart(total_tasks, remaining_tasks, done_tasks):
    # Clear the previous pie chart
    for widget in pie_chart_frame.winfo_children():
        widget.destroy()

    if total_tasks == 0:
        return  # No tasks to display

    # Create a new pie chart
    labels = 'Completed Tasks', 'Remaining Tasks'
    sizes = [done_tasks, remaining_tasks]
    colors = ['#4caf50', '#ffeb3b']
    explode = (0.1, 0)  # explode the 1st slice (Completed Tasks)

    fig, ax = plt.subplots(figsize=(5, 3), dpi=100)  # Adjust the size and DPI as needed
    fig.patch.set_facecolor('#0d1525')  # Match the Tkinter background color

    ax.pie(sizes, explode=explode, colors=colors, autopct='%1.1f%%',
           shadow=True, startangle=140)
    ax.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.

    # Add a legend
    ax.legend(labels, loc="best")

    # Embed the pie chart into Tkinter
    canvas_chart = FigureCanvasTkAgg(fig, master=pie_chart_frame)
    canvas_chart.draw()
    canvas_chart.get_tk_widget().pack()

    plt.close(fig)  # Close the figure to release memory

# Function to save tasks to a file
def save_tasks():
    with open("tasks.txt", "w") as file:
        for task_frame in task_container.winfo_children():
            task_label = task_frame.winfo_children()[0]
            task_text = task_label.cget("text").split(". ", 1)[1]
            task_done = "1" if "overstrike" in task_label.cget("font") else "0"
            file.write(f"{task_text}|{task_done}\n")
    messagebox.showinfo("Save Tasks", "Tasks have been saved successfully.")

# Function to load tasks from a file
def load_tasks():
    try:
        with open("tasks.txt", "r") as file:
            for line in file:
                task_text, task_done = line.strip().split("|")
                add_task(task_text)
                if task_done == "1":
                    task_frame = task_container.winfo_children()[-1]
                    task_label = task_frame.winfo_children()[0]
                    done_button = task_frame.winfo_children()[1]
                    mark_as_done(task_label, done_button)
        update_task_count()
    except FileNotFoundError:
        pass  # No file to load from

# Create a canvas to allow scrolling
canvas = tk.Canvas(newWindow, bg="#0d1525")
canvas.pack(side=tk.LEFT, fill=tk.BOTH, expand=True)

# Create a scrollbar
scrollbar = tk.Scrollbar(newWindow, orient="vertical", command=canvas.yview)
scrollbar.pack(side=tk.LEFT, fill="y")

# Configure the canvas
canvas.configure(yscrollcommand=scrollbar.set)
canvas.bind('<Configure>', lambda e: canvas.configure(scrollregion=canvas.bbox("all")))

# Create a frame inside the canvas
task_container = tk.Frame(canvas, bg="#0d1525")
canvas.create_window((0, 0), window=task_container, anchor="nw")

# Create a navigation bar heading
nav_frame = tk.Frame(newWindow, bg="#1d2332")
nav_frame.pack(fill=tk.X)

nav_label = tk.Label(nav_frame, text="To-Do List", bg="#1d2332", fg="red", font=("Helvetica", 24, "bold"))
nav_label.pack(pady=10)

# Create an entry widget for adding tasks
task_entry = tk.Entry(newWindow, width=35, bg="#1d2332", fg="#ffffff", font=("Helvetica", 22))
task_entry.pack(pady=10)

# Create a button to add tasks
add_task_button = tk.Button(newWindow, text="Add Task", command=add_task, bg="#add8e6", fg="#000000", font=("Helvetica", 12))
add_task_button.pack(pady=5)
# Create a button to delete all tasks
delete_all_button = tk.Button(newWindow, text="Delete All Tasks", command=delete_all_tasks, bg="#ff6347", fg="#000000", font=("Helvetica", 12))
delete_all_button.pack(pady=5)

# Create buttons to save and load tasks
save_button = tk.Button(newWindow, text="Save Tasks", command=save_tasks, bg="#4caf50", fg="#000000", font=("Helvetica", 12))
save_button.pack(pady=5)

load_button = tk.Button(newWindow, text="Load Tasks", command=load_tasks, bg="#ffc107", fg="#000000", font=("Helvetica", 12))
load_button.pack(pady=5)

# Add vertical gap
tk.Label(newWindow, text="", bg="#0d1525").pack(pady=10)

# Labels to display task counts
total_tasks_label = tk.Label(newWindow, text="Total Tasks: 0", bg="#0d1525", fg="#ffffff", font=("Helvetica", 18))
total_tasks_label.pack(pady=2)

remaining_tasks_label = tk.Label(newWindow, text="Remaining Tasks: 0", bg="#0d1525", fg="yellow", font=("Helvetica", 18))
remaining_tasks_label.pack(pady=2)

done_tasks_label = tk.Label(newWindow, text="Completed Tasks: 0", bg="#0d1525", fg="lime", font=("Helvetica", 18))
done_tasks_label.pack(pady=2)

# Frame for the pie chart
pie_chart_frame = tk.Frame(newWindow, bg="#0d1525")
pie_chart_frame.pack(pady=20)

# Run the main loop
newWindow.mainloop()

If you want the full explanation of this code you can watch this playlist available  on the YouTube.