How to Create a Swing Login Window?

The following program demonstrates How to Create a Swing Login Window.

In order to create a Swing login window to check a username and password using text fields and command buttons, you can use the following Java program.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class LoginWindow extends JFrame {
    private JTextField usernameField;
    private JPasswordField passwordField;
    private JButton loginButton;
    private JLabel resultLabel;

    public LoginWindow() {
        setTitle("Login Window");
        setSize(300, 150);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(3, 2));

        JLabel usernameLabel = new JLabel("Username:");
        usernameField = new JTextField(20);

        JLabel passwordLabel = new JLabel("Password:");
        passwordField = new JPasswordField(20);

        loginButton = new JButton("Login");
        loginButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String username = usernameField.getText();
                char[] passwordChars = passwordField.getPassword();
                String password = new String(passwordChars);

                if (isValidUser(username, password)) {
                    resultLabel.setText("Login Successful!");
                } else {
                    resultLabel.setText("Invalid username or password. Please try again.");
                }
            }
        });

        resultLabel = new JLabel("");

        panel.add(usernameLabel);
        panel.add(usernameField);
        panel.add(passwordLabel);
        panel.add(passwordField);
        panel.add(loginButton);

        add(panel, BorderLayout.CENTER);
        add(resultLabel, BorderLayout.SOUTH);

        setVisible(true);
    }

    private boolean isValidUser(String username, String password) {
        // Replace this with your actual authentication logic
        // For simplicity, we're checking if the username is "user" and the password is "password"
        return "user".equals(username) && "password".equals(password);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new LoginWindow();
            }
        });
    }
}

In this program:

We create a LoginWindow class that extends JFrame to create the main login window.
Inside the constructor:
- We set the title, size, and close operation for the frame.
- Then, we create Swing components such as JLabel, JTextField, JPasswordField, JButton, and JLabel for displaying the result.
- Further, we add an ActionListener to the login button to validate the username and password when the button is clicked.
The isValidUser method is used to simulate user authentication. You should replace it with your actual authentication logic.
Finally, we use SwingUtilities.invokeLater to create an instance of the LoginWindow on the Swing Event Dispatch Thread.

When you run this program, you’ll see a Swing-based login window where users can enter a username and password. So, when the “Login” button is clicked, it checks the credentials and displays a message accordingly.

Further Reading