《Java2图形设计卷II：Swing》配套光盘源码

				import javax.swing.*;
				import javax.swing.event.*;
				import javax.swing.plaf.basic.*;
				import java.awt.*;
				import java.awt.event.*;
				import java.beans.*;
				
				public class Test extends JApplet {
					public void init() {
						Container contentPane = getContentPane();
						final JSlider slider = new JSlider();
						final JCheckBox checkBox = new JCheckBox("Annotate");
				
						slider.setUI(new AnnotatedSliderUI(slider));
				
						contentPane.setLayout(new FlowLayout());
						contentPane.add(checkBox);
						contentPane.add(slider);
				
						checkBox.addActionListener(new ActionListener() {
							public void actionPerformed(ActionEvent e) {
								boolean selected = checkBox.isSelected();
				
								slider.putClientProperty(
										AnnotatedSliderUI.ANNOTATE_PROPERTY, 
										selected ? Boolean.TRUE : Boolean.FALSE);
				
								slider.repaint();
							}
						});
					}
				}
				class AnnotatedSliderUI extends BasicSliderUI {
					public static String ANNOTATE_PROPERTY = 
										 			"AnnotatedSliderUI.annotate";
					boolean annotate = false;
				
					public AnnotatedSliderUI(JSlider slider) {
						super(slider);
					}
					public Dimension getPreferredSize(JComponent c) {
						Dimension d = super.getPreferredSize(c);
						return new Dimension(d.width,d.height+20);
					}
					public void paint(Graphics g, JComponent c) {
						if(annotate) {
							JSlider slider = (JSlider)c;
							int v = slider.getValue();
				
							g.setColor(UIManager.getColor("Label.foreground"));
							g.setFont(new Font("Dialog", Font.PLAIN, 28));
							g.drawString((new Integer(v)).toString(),10,33);
						}
						super.paint(g,c);
					}
					protected PropertyChangeListener 
								createPropertyChangeListener(JSlider slider) {
						return new AnnotatePropertyListener();
					}
					protected class AnnotatePropertyListener 
									extends BasicSliderUI.PropertyChangeHandler {
				        public void propertyChange(PropertyChangeEvent e) {
							System.out.println("property changed");
					    	super.propertyChange(e);
				
					    	String name = e.getPropertyName();
				
					    	if(name.equals(ANNOTATE_PROPERTY)) {
							System.out.println("property changed");
					        	if(e.getNewValue() != null) {
						    		annotate = 
										((Boolean)e.getNewValue()).booleanValue();
								}
							}
					    }
				    }
				}