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Lesson 4: Introduction to Java Swing

Objective:​

In this lesson, you'll understand the basics of Java Swing and how it integrates with Java programming to create graphical user interfaces (GUIs). You'll set up a simple window, add components, and learn how Swing fits within Java's ecosystem.

What is Java Swing?​

Java Swing is a part of Java's Standard Library, offering a rich set of GUI components to build applications that can interact with the user visually. Swing is built on top of AWT (Abstract Window Toolkit), but unlike AWT, Swing provides a more flexible and feature-rich platform for creating graphical interfaces.

Setting Up the Environment​

Before you can start coding with Swing, you need to make sure that your development environment is ready:

  1. Download and Install JDK (Java Development Kit):
  2. IDE Setup:
    You can use any IDE, but I recommend using Eclipse, NetBeans, or IntelliJ IDEA for their built-in support for Swing development.

Code Example: Simple JFrame with JLabel​

Let’s start by creating a basic window using JFrame and a simple JLabel.

import javax.swing.JFrame;
import javax.swing.JLabel;

public class HelloSwing {
    public static void main(String[] args) {
        // Create a JFrame (Main window)
        JFrame frame = new JFrame("Hello Java Swing");

        // Create a JLabel (Text component)
        JLabel label = new JLabel("Welcome to Java Swing!");

        // Add the label to the frame
        frame.add(label);

        // Set frame properties
        frame.setSize(400, 200);  // Set the size of the window
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  // Close the app when the window is closed
        frame.setVisible(true);  // Make the window visible
    }
}

Code Explanation:​

  1. JFrame: This is the main window of your application. It acts as the container for all other components.
  2. JLabel: A simple text component that is displayed on the window.
  3. frame.add(label): Adds the label to the frame.
  4. frame.setSize(400, 200): Sets the size of the window (width: 400px, height: 200px).
  5. frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE): Ensures that the application closes when the user closes the window.
  6. frame.setVisible(true): Makes the window visible on the screen.