test.java

《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 {
	public Test() {
		Container contentPane = getContentPane();
		JViewport viewport = new JViewport();
		JPanel view = new JPanel();

		view.add(new JLabel(
					new ImageIcon("anjinAndMariko.gif")));

		viewport.setView(view);

		contentPane.add(new ControlPanel(viewport), 
						BorderLayout.NORTH);
		contentPane.add(viewport, BorderLayout.CENTER);
		contentPane.add(new StatusPanel(viewport),
						BorderLayout.SOUTH);
	}
}
class StatusPanel extends JPanel { 
	private JLabel extentLabel = new JLabel(),
					viewPositionLabel = new JLabel(),
					viewSizeLabel = new JLabel();
	private JViewport viewport;

	public StatusPanel(JViewport vp) {
		viewport = vp;

		setBorder(BorderFactory.createEtchedBorder());
		setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));

		extentLabel.setAlignmentX(0.5f);
		viewPositionLabel.setAlignmentX(0.5f);
		viewSizeLabel.setAlignmentX(0.5f);

		add(extentLabel);
		add(viewPositionLabel);
		add(viewSizeLabel);

		viewport.addChangeListener(new ChangeListener() {
			public void stateChanged(ChangeEvent e) {
				Dimension extent = viewport.getExtentSize();
				Point viewPosition = viewport.getViewPosition();
				Rectangle viewSize = viewport.getViewRect();

				extentLabel.setText("View Extent: " + 
										extent.toString());
				viewPositionLabel.setText("View Position: " + 
										viewPosition.toString());
				viewSizeLabel.setText("View Size: " + 
									viewSize.toString());
				revalidate();
			}
		});
	}
}
class ControlPanel extends JPanel { 
	private JViewport viewport;

	private JButton[] buttons = {
		new JButton("up"), new JButton("down"),
		new JButton("left"), new JButton("right"),
	};

	public ControlPanel(JViewport vp) {
		viewport = vp;

		for(int i=0; i < buttons.length; ++i) {
			add(buttons[i]);

			buttons[i].addActionListener(new ActionListener() {
				public void actionPerformed(ActionEvent e) {
					scroll(e.getActionCommand());
				}
			});
		}
	}
	private void scroll(String actionCmd) {
		Point vp = viewport.getViewPosition();

		if(actionCmd.equals("up")) vp.y += 5;	
		else if(actionCmd.equals("down")) vp.y -= 5;	
		else if(actionCmd.equals("left")) vp.x += 5;	
		else if(actionCmd.equals("right")) vp.x -= 5;	

		viewport.setViewPosition(vp);
	}
}