complete13_1.java

北京大学出版社的

package questions.c13;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Complete13_1 extends JFrame {
   private JPanel upperPanel, midPanel, lowerPanel;
   private JTextField text;
   private JButton blackButton, redButton, greenButton;
   private JCheckBox disableCheck;
   public Complete13_1( String titleText ) {
      super( titleText );
      addWindowListener( new WindowAdapter() {
            public void windowClosing( WindowEvent e ) {
               e.getWindow().dispose();
               System.exit( 0 );
            }
         }
      );
      ButtonListener aListener = new ButtonListener();
      CheckboxHandler cbHandler = new CheckboxHandler();
      upperPanel = new JPanel();
      upperPanel.setLayout( new BorderLayout() );
      text = new JTextField(
         "Change the color of this text" );
      upperPanel.add( text, BorderLayout.CENTER );
      midPanel = new JPanel();
      midPanel.setLayout(
         new FlowLayout( FlowLayout.CENTER ) );
      blackButton = new JButton( "Black" );
      midPanel.add( blackButton );
      blackButton.addActionListener( aListener );
      redButton = new JButton( "Red" );
      midPanel.add( redButton );
      redButton.addActionListener( aListener );
      greenButton = new JButton( "Green" );
      midPanel.add( greenButton );
      greenButton.addActionListener( aListener );
      lowerPanel = new JPanel();
      lowerPanel.setLayout(
         new FlowLayout( FlowLayout.RIGHT ) );
      disableCheck = new JCheckBox( "Disable changes" );
      disableCheck.addItemListener( cbHandler );
      lowerPanel.add( disableCheck );
      Container cp = getContentPane();      
      cp.add( upperPanel, BorderLayout.NORTH );
      cp.add( midPanel, BorderLayout.CENTER );
      cp.add( lowerPanel, BorderLayout.SOUTH );
      pack();
      setVisible( true );
   }
   class ButtonListener implements ActionListener {
      public void actionPerformed(ActionEvent e) {
         Object source = e.getSource();
         if ( source == redButton ) {
            text.setForeground( Color.red );
            text.invalidate();
         } else if ( source == greenButton ) {
            text.setForeground( Color.green );
            text.invalidate();
         } else if ( source == blackButton ) {
            text.setForeground( Color.black );
            text.invalidate();
         }
      }
   }

   // put your CheckboxHandler class definition here

   public static void main( String[] args ) {
      new Complete13_1( "Complete the Solution" );
   }
}