listrenderingtest.java

这个是我老师给的关于Java核心技术2的第6章的源代码

/**
   @version 1.22 2004-08-21
   @author Cay Horstmann
*/

import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

/**
   This program demonstrates the use of cell renderers in
   a list box.
*/
public class ListRenderingTest
{  
   public static void main(String[] args)
   {  
      JFrame frame = new ListRenderingFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setVisible(true);
   }
}

/**
   This frame contains a list with a set of fonts and a text
   area that is set to the selected font.
*/
class ListRenderingFrame extends JFrame
{  
   public ListRenderingFrame()
   {  
      setTitle("ListRenderingTest");
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      ArrayList<Font> fonts = new ArrayList<Font>();
      final int SIZE = 24;
      fonts.add(new Font("Serif", Font.PLAIN, SIZE));
      fonts.add(new Font("SansSerif", Font.PLAIN, SIZE));
      fonts.add(new Font("Monospaced", Font.PLAIN, SIZE));
      fonts.add(new Font("Dialog", Font.PLAIN, SIZE));
      fonts.add(new Font("DialogInput", Font.PLAIN, SIZE));
      fontList = new JList(fonts.toArray());
      fontList.setVisibleRowCount(4);
      fontList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
      fontList.setCellRenderer(new FontCellRenderer());
      JScrollPane scrollPane = new JScrollPane(fontList);

      JPanel p = new JPanel();
      p.add(scrollPane);
      fontList.addListSelectionListener(new
         ListSelectionListener()
         {
            public void valueChanged(ListSelectionEvent evt)
            {  
               Font font = (Font) fontList.getSelectedValue();
               text.setFont(font);
            }

         });

      Container contentPane = getContentPane();
      contentPane.add(p, BorderLayout.SOUTH);
      text = new JTextArea("The quick brown fox jumps over the lazy dog");
      text.setFont((Font) fonts.get(0));
      text.setLineWrap(true);
      text.setWrapStyleWord(true);
      contentPane.add(text, BorderLayout.CENTER);
   }

   private JTextArea text;
   private JList fontList;
   private static final int DEFAULT_WIDTH = 400;
   private static final int DEFAULT_HEIGHT = 300;
}

/**
   A cell renderer for Font objects that renders the font name in its own font.
*/
class FontCellRenderer extends JPanel implements ListCellRenderer
{  
   public Component getListCellRendererComponent(JList list, Object value, int index, 
      boolean isSelected, boolean cellHasFocus)
   {  
      font = (Font) value;
      background = isSelected ? list.getSelectionBackground() : list.getBackground();
      foreground = isSelected ? list.getSelectionForeground() : list.getForeground();
      return this;
   }

   public void paintComponent(Graphics g)
   {                 
      String text = font.getFamily();
      FontMetrics fm = g.getFontMetrics(font);
      g.setColor(background);
      g.fillRect(0, 0, getWidth(), getHeight());
      g.setColor(foreground);
      g.setFont(font);
      g.drawString(text, 0, fm.getAscent());
   }
   
   public Dimension getPreferredSize()
   {  
      String text = font.getFamily();
      Graphics g = getGraphics();
      FontMetrics fm = g.getFontMetrics(font);
      return new Dimension(fm.stringWidth(text), fm.getHeight());
   }

   private Font font;
   private Color background;
   private Color foreground;
}