Event Handling

Swing Event Handling Event Handling in Swing is based on the delegation event model, where an event source (component) notifies one or more listeners when an event occurs. Key Concepts Event Source: The component that generates an event (e.g., JButton) Event Listener: An interface that receives and processes the event (e.g., ActionListener) Event Object: Carries information about the event (e.g., ActionEvent) Example: Handling Button Click import javax.swing.*; import java.awt.event.*; public class EventExample { public static void main(String[] args) { JFrame frame = new JFrame("Event Example"); JButton button = new JButton("Click Me"); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { System.out.println("Button clicked!"); } }); frame.add(button); frame.setSize(200, 150); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } } Lambda Version (Java 8+) button.addActionListener(e -> System.out.println("Clicked!")); Event Flow User interacts with a component (e.g., clicks a button). Component generates an event object. Event object is passed to the registered listener’s method. 🔗 Related Notes Event Listeners Event Classes and Listener Interfaces Swing Controls