comboboxdemo3.java

java 完全探索的随书源码

// ComboBoxDemo3.java

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

class ComboBoxDemo3 extends JFrame
{
   ImageIcon [] im;

   ComboBoxDemo3 (String title)
   {
      super (title);

      addWindowListener (new WindowAdapter ()
                         {
                             public void windowClosing (WindowEvent e)
                             {
                                System.exit (0);
                             }
                         });

      im = new ImageIcon [2];

      im [0] = new ImageIcon ("dime.gif");
      im [0].setDescription ("Dime");

      im [1] = new ImageIcon ("penny.gif");
      im [1].setDescription ("Penny");

      JComboBox coins = new JComboBox (im);
      ComboBoxRenderer renderer = new ComboBoxRenderer ();
      renderer.setPreferredSize (new Dimension (200, 100));
      coins.setRenderer (renderer);

      getContentPane ().add (coins);

      pack ();
      setVisible (true);
   }

   public static void main (String [] args)
   {
      new ComboBoxDemo3 ("Combo box Demo3");
   }
}

class ComboBoxRenderer extends JLabel implements ListCellRenderer
{
   public ComboBoxRenderer ()
   {
      setOpaque (true);
      setHorizontalAlignment (CENTER);
      setVerticalAlignment (CENTER);
   }

   public Component getListCellRendererComponent (JList list,
                                                  Object value,
                                                  int index,
                                                  boolean selected,
                                                  boolean hasfocus)
   {
      if (selected)
      {
          setBackground (list.getSelectionBackground ());
          setForeground (list.getSelectionForeground ());
      }
      else
      {
          setBackground (list.getBackground ());
          setForeground (list.getForeground ());
      }

      ImageIcon icon = (ImageIcon) value;
      setText (icon.getDescription ());
      setIcon (icon);
      return this;
   }
}