《Java2图形设计卷II：Swing》配套光盘源码

				import java.awt.*;
				import java.awt.event.*;
				import javax.swing.*;
				
				public class Test extends JApplet {
					public void init() {
						Container contentPane = getContentPane();
						JViewport columnHeaderViewport = new JViewport();
						JViewport rowHeaderViewport = new JViewport();
				
						JLabel columnHeaderView = new JLabel(
											new ImageIcon("horizontalRuler.jpg"));
						JLabel rowHeaderView = new JLabel(
											new ImageIcon("verticalRuler.jpg"));
						JLabel view = new JLabel(
											new ImageIcon("strawberry.jpg"));
				
						JScrollPane sp = new JScrollPane(view);
				
						sp.setToolTipText(
									"Drag the headers to drag the picture!");
				
						HeaderViewDragListener verticalHeaderListener = 
									new HeaderViewDragListener(sp, 
												SwingConstants.VERTICAL);
				
						HeaderViewDragListener horizontalHeaderListener = 
									new HeaderViewDragListener(sp, 
												SwingConstants.HORIZONTAL);
				
						columnHeaderViewport.addMouseListener(
														horizontalHeaderListener);
						columnHeaderViewport.addMouseMotionListener(
														horizontalHeaderListener);
				
						rowHeaderViewport.addMouseListener(
														verticalHeaderListener);
						rowHeaderViewport.addMouseMotionListener(
														verticalHeaderListener);
				
						// headers must be set before header views
						sp.setColumnHeader(columnHeaderViewport);
						sp.setRowHeader(rowHeaderViewport);
				
						sp.setColumnHeaderView(columnHeaderView);
						sp.setRowHeaderView(rowHeaderView);
				
						contentPane.add(sp);
					}
				}
				class HeaderViewDragListener extends MouseAdapter
												implements MouseMotionListener,
															SwingConstants {
					private Point last = new Point();
					private JScrollPane scrollpane; 
					private int orientation;
				
					public HeaderViewDragListener(JScrollPane sp, int orient) {
						scrollpane = sp;
						orientation = orient;
					}
					public void mousePressed(MouseEvent e) {
						last.x = e.getPoint().x;
						last.y = e.getPoint().y;
					}
					public void mouseMoved(MouseEvent e) {
					}
					public void mouseDragged(MouseEvent e) {
						JViewport headerViewport = (JViewport)e.getSource();
						JViewport scrollpaneViewport = scrollpane.getViewport();
						Dimension viewSize = scrollpaneViewport.getViewSize(),
								  extent = scrollpaneViewport.getExtentSize();
				
						Point drag = e.getPoint();
						Point offset = new Point(drag.x-last.x, drag.y-last.y);
						Point headerPosition = new Point(), viewportPosition;
				
						viewportPosition = scrollpaneViewport.getViewPosition();
				
						if(orientation == HORIZONTAL) {
							int nextX = viewportPosition.x - offset.x;
							int rightEdge = extent.width + nextX;
				
							if(nextX > 0 && rightEdge < viewSize.width) {
								headerPosition.x = nextX;
								viewportPosition.x = nextX;
							}
						}
						if(orientation == VERTICAL)  {	
							int nextY = viewportPosition.y - offset.y;
							int bottomEdge = extent.height + nextY;
				
							if(nextY > 0 && bottomEdge < viewSize.height) {
								headerPosition.y = nextY;
								viewportPosition.y = nextY;
							}
						}
						headerViewport.setViewPosition(headerPosition);
						scrollpaneViewport.setViewPosition(viewportPosition);
				
						last.x = drag.x;
						last.y = drag.y;
					}
				}