Build a Python-based to-do list app

Here’s a basic Python-based To-Do List App using the tkinter library for a simple GUI interface. This app allows users to add, delete, and save tasks.

python
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import tkinter as tk
from tkinter import messagebox
import os

TASKS_FILE = "tasks.txt"

class ToDoApp:
    def __init__(self, root):
        self.root = root
        self.root.title("To-Do List App")
        self.root.geometry("400x450")
        self.root.configure(bg="#f0f0f0")

        self.tasks = []

        self.title = tk.Label(root, text="My To-Do List", font=("Helvetica", 18, "bold"), bg="#f0f0f0")
        self.title.pack(pady=10)

        self.task_entry = tk.Entry(root, font=("Helvetica", 14), width=30)
        self.task_entry.pack(pady=10)

        self.add_btn = tk.Button(root, text="Add Task", font=("Helvetica", 12), width=15, command=self.add_task)
        self.add_btn.pack(pady=5)

        self.task_listbox = tk.Listbox(root, font=("Helvetica", 14), width=35, height=10, selectbackground="lightblue")
        self.task_listbox.pack(pady=10)

        self.del_btn = tk.Button(root, text="Delete Selected", font=("Helvetica", 12), width=15, command=self.delete_task)
        self.del_btn.pack(pady=5)

        self.save_btn = tk.Button(root, text="Save Tasks", font=("Helvetica", 12), width=15, command=self.save_tasks)
        self.save_btn.pack(pady=5)

        self.load_tasks()

    def add_task(self):
        task = self.task_entry.get().strip()
        if task:
            self.tasks.append(task)
            self.update_listbox()
            self.task_entry.delete(0, tk.END)
        else:
            messagebox.showwarning("Warning", "Task cannot be empty")

    def delete_task(self):
        selected = self.task_listbox.curselection()
        if selected:
            index = selected[0]
            self.tasks.pop(index)
            self.update_listbox()
        else:
            messagebox.showwarning("Warning", "No task selected")

    def update_listbox(self):
        self.task_listbox.delete(0, tk.END)
        for task in self.tasks:
            self.task_listbox.insert(tk.END, task)

    def save_tasks(self):
        with open(TASKS_FILE, "w") as f:
            for task in self.tasks:
                f.write(task + "n")
        messagebox.showinfo("Saved", "Tasks saved successfully!")

    def load_tasks(self):
        if os.path.exists(TASKS_FILE):
            with open(TASKS_FILE, "r") as f:
                self.tasks = [line.strip() for line in f.readlines()]
            self.update_listbox()

if __name__ == "__main__":
    root = tk.Tk()
    app = ToDoApp(root)
    root.mainloop()

Features:

• Add a task.

• Delete selected task.

• Save tasks to a file (tasks.txt).

• Load saved tasks on startup.

Requirements:

• Works out of the box with Python 3.

• No external packages required.

Let me know if you want an advanced version with categories, priorities, or due dates.