Todo list app using Flask | Python

There are many frameworks which allow to build your webpage using Python, like django, flask etc. Flask is a web application framework written in Python. Flask is based on WSGI(Web Server Gateway Interface) toolkit and Jinja2 template engine. Its modules and libraries that help the developer to write applications without writing the low-level codes such as protocols, thread management, etc.

In this article, we will learn how to make a todo list app using Flask framework. In this app, you can add your todo items and mark them as complete or incomplete.

Installation:



 pip install Flask

1. Create the main python app file as app.py and write the code.

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from flask import Flask, render_template, request, redirect, url_for
from flask_sqlalchemy import SQLAlchemy 
  
app = Flask(__name__)
####### Database#######
  
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////home/somil/Desktop/todo/todo.db'
  
db = SQLAlchemy(app)
  
class Todo(db.Model):
    id = db.Column(db.Integer, primary_key = True)
    text = db.Column(db.String(200))
    complete = db.Column(db.Boolean)
  
###### Route when nothing is specified in the url###### 
@app.route('/')
def index():
    incomplete = Todo.query.filter_by(complete = False).all()
    complete = Todo.query.filter_by(complete = True).all()
  
    return render_template('index.html'
       incomplete = incomplete, complete = complete)
  
###### Adding items######
@app.route('/add', methods =['POST'])
def add():
    todo = Todo(text = request.form['todoitem'], complete = False)
    db.session.add(todo)
    db.session.commit()
  
###### Makes to stay on the same home page###### 
return redirect(url_for('index'))
  
###### Complete items######
@app.route('/complete/<id>')
def complete(id):
  
    todo = Todo.query.filter_by(id = int(id)).first()
    todo.complete = True
    db.session.commit()
    ###### Makes to stay on the same home page###### 
  
return redirect(url_for('index'))
  
if __name__ == '__main__':
    app.run(debug = True)

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2. Create the user interface part using html. Give the layout to the app

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Todo App</title>
    <link rel="stylesheet" type="text/css" href="{{url_for('static', filename='main.css')}}">
  
</head>
<body>
    <h1>Todo List</h1>
    <div>Add a new todo item: 
        <form action="{{ url_for('add') }}" method="POST">
            <input type="text" name="todoitem">
            <input type="submit" value="Add Item" class="button">
        </form>
    </div>
    <div>
        <h2>Incomplete Items</h2>
        <ul>
            {% for todo in incomplete %}
            <li style="font-size: 30pt" class='mark'>{{ todo.text }} <a href="{{ url_for('complete', id=todo.id) }}">Mark As Complete</a></li>
            {% endfor %}    
        </ul>
        <h2>Completed Items</h2>
        <ul>
            {% for todo in complete %}
            <li style="font-size: 30pt">{{ todo.text }}</li>
            {% endfor %}
        </ul>
    </div>
</body>
</html>

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3. Create the static files like css and any other styling part

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body{
    background:black;
    color:red;
    margin-top: 5px;
}
.button{
    color:green;
}
.mark{font-size: 10px;}

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After creating the files, create the database using sqlite3. Open the .db file created in your project file using sqlite3.

Create table in the database using .tables command

Open python in terminal and import the db file created to create tables

Now run the app.py file on terminal.

python3 app.py

Output:



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