《Java2图形设计卷II：Swing》配套光盘源码

				import java.awt.*;
				import java.awt.event.*;
				import javax.swing.*;
				import javax.swing.event.*;
				
				public class Test extends JApplet {
					private JTextField textField = new JTextField(
						"12345678901234567890123456789012345678901234567890", 10);
				
					public void init() {
						Container contentPane = getContentPane();
						JPanel textFieldPanel = new JPanel();
				
						textFieldPanel.add(textField);
				
						contentPane.add(new ControlPanel(), BorderLayout.NORTH);
						contentPane.add(textFieldPanel, BorderLayout.CENTER);
					}
					class ControlPanel extends JPanel {
						private JLabel display = new JLabel(" ");
						private JSlider slider = new JSlider(
											textField.getHorizontalVisibility());
						private JComboBox columns = new JComboBox();
				
						public ControlPanel() {
							columns.addItem(new Integer(0));
							columns.addItem(new Integer(5));
							columns.addItem(new Integer(10));
							columns.addItem(new Integer(15));
				
							columns.setSelectedIndex(2);
				
							add(new JLabel("Scroll Offset:"));
							add(slider);
							add(display);
							add(Box.createHorizontalStrut(10));
							add(new JLabel("Columns:"));
							add(columns);
				
							slider.addChangeListener(new ChangeListener() {
								public void stateChanged(ChangeEvent e) {
									textField.setScrollOffset(slider.getValue());
				
									Integer i = 
										new Integer(textField.getScrollOffset());
									BoundedRangeModel m =
											textField.getHorizontalVisibility();
										
									display.setText(i.toString());
				
									showStatus("Visibility -  min: " + 
											   m.getMinimum() + 
											   ", max: " + m.getMaximum() +
											   ", extent: " + m.getExtent() + 
											   ", value: " + m.getValue() +
											   ", isAdj: " + 
											   m.getValueIsAdjusting());
								}
							});
							columns.addActionListener(new ActionListener() {
								public void actionPerformed(ActionEvent e) {
									Integer c = 
										(Integer)columns.getSelectedItem();
				
									textField.setColumns(c.intValue());
				
									// the following call to revalidate()
									// should not be necessary
									revalidate();
				
									textField.setScrollOffset(0);
								}
							});
						}
					}
				}