Event Handling
Feb 14, 2000
Event Model Revisited
Recall that a component can fire an event.
Each type of event is defined as a distinct class.
An event is received by one or more listeners.
An event listener is an object of a class which implements particular type of listener interface
Since a class can implement multiple interfaces, an object can act on multiple events of different types.
To receive an event of particular type, we only need to register with the component that fire the event.
Event Hierarchy
java.util.EventObject
java.awt.AWTEvent
java.awt.event.ComponentEvent
java.awt.event.FocusEvent
java.awt.event.KeyEvent
java.awt.event.MouseEvent
java.awt.event.AdjustmentEvent
java.awt.event.WindowEvent
java.awt.event.ActionEvent
java.awt.event.ItemEvent
java.awt.event.TextEvent
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ButtonDemo implements ActionListener {
Container pane;
ButtonDemo() {
JFrame frame =
new JFrame("Button Demo");
pane = frame.getContentPane();
pane.setLayout(new GridLayout(5,3));
addButtons();
frame.pack();
frame.setSize(300,200);
frame.setVisible(true);
}
// place addButtons() here!!!
public void actionPerformed(
ActionEvent event) {
String command
= event.getActionCommand();

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