Guide to Creating a Login Form in Python Using PyQT6

A detailed guide on how to create a login form in Python using PyQT6, including designing the interface and handling the login button event.

In this article, you'll learn how to create a login form using PyQT6 in Python. We will build an interface with input fields like username and password, and handle the event when the "Login" button is clicked.

Python Code

import sys  # System library for interacting with the Python interpreter
from PyQt6.QtWidgets import QApplication, QWidget, QLabel, QLineEdit, QVBoxLayout, QPushButton, QMessageBox  # Import required classes from PyQt6

# Create a LoginForm class that inherits from QWidget
class LoginForm(QWidget):
    def __init__(self):
        super().__init__()  # Call the constructor of the parent class QWidget
        self.initUI()  # Call a function to initialize the UI

    def initUI(self):
        self.setWindowTitle('Account Login Form')  # Set the window title
        self.setGeometry(100, 100, 400, 200)  # Set the window's position and size (x, y, width, height)

        # Create a vertical box layout
        layout = QVBoxLayout()

        # Create and add input fields to the layout
        self.username_label = QLabel('Username:', self)
        layout.addWidget(self.username_label)
        self.username_input = QLineEdit(self)
        layout.addWidget(self.username_input)

        self.password_label = QLabel('Password:', self)
        layout.addWidget(self.password_label)
        self.password_input = QLineEdit(self)
        self.password_input.setEchoMode(QLineEdit.EchoMode.Password)  # Set password echo mode
        layout.addWidget(self.password_input)

        # Create and add the login button
        self.login_button = QPushButton('Login', self)
        self.login_button.clicked.connect(self.login)  # Connect the button click event to the login function
        layout.addWidget(self.login_button)

        # Set the main layout for the widget
        self.setLayout(layout)

    # Define the function to handle the login button click
    def login(self):
        username = self.username_input.text()
        password = self.password_input.text()

        if username == "admin" and password == "password":
            QMessageBox.information(self, 'Notification', 'Login successful!')
        else:
            QMessageBox.warning(self, 'Error', 'Invalid username or password!')

# Main part of the application
if __name__ == '__main__':
    app = QApplication(sys.argv)  # Initialize the QApplication object
    form = LoginForm()  # Create an instance of the LoginForm class
    form.show()  # Display the interface
    sys.exit(app.exec())  # Run the application's event loop

Detailed explanation:

1. import sys: Import the system library.
2. from PyQt6.QtWidgets import ...: Import the necessary classes from PyQt6.
3. class LoginForm(QWidget): Define the LoginForm class inheriting from QWidget.
4. def __init__(self): The constructor of the LoginForm class.
5. self.initUI(): Call the initUI function to initialize the user interface.
6. self.setWindowTitle('...'): Set the window title.
7. self.setGeometry(...): Set the window position and size.
8. layout = QVBoxLayout(): Create a vertical box layout.
9. self.username_label = QLabel('...'): Create labels and input fields for username.
10. self.password_input.setEchoMode(...): Set the echo mode for the password input.
11. self.login_button.clicked.connect(...): Connect the button click event to the login function.
12. def login(self): Define the login function to handle the button click.
13. QMessageBox.information(...): Display a success or error message.

System Requirements:

• Python 3.9 or above
• PyQT6

Installation instructions:

Use pip to install PyQt6:

pip install PyQt6

Tips:

• You can expand the login form with additional features like checking data from a database.
• Consider implementing password hashing for better security in your application.