menutest.java

JAVA 2应用开发指南

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MenuTest extends JFrame {
  private Color colorValues[] ={ Color.black, Color.blue, Color.red, Color.green };
  private JRadioButtonMenuItem colorItems[], fonts[];
  private JCheckBoxMenuItem styleItems[];
  private JLabel displayLabel;
  private ButtonGroup fontGroup, colorGroup;
  private int style;
  public MenuTest(){
    super( "Using JMenus" );
    JMenu fileMenu = new JMenu( "File" );
    fileMenu.setMnemonic( 'F' );
    JMenuItem aboutItem = new JMenuItem( "About..." );
    aboutItem.setMnemonic( 'A' );
    aboutItem.addActionListener( new ActionListener() {
      public void actionPerformed( ActionEvent event ){
         JOptionPane.showMessageDialog(MenuTest.this,"This is an example\nof using menus","About", JOptionPane.PLAIN_MESSAGE );
      }
    }); // end call to addActionListener
    fileMenu.add( aboutItem );
    JMenuItem exitItem = new JMenuItem( "Exit" );
    exitItem.setMnemonic( 'x' );
    exitItem.addActionListener(new ActionListener() {
      public void actionPerformed( ActionEvent event ){
        System.exit( 0 );
     }
    });
    fileMenu.add( exitItem );
    JMenuBar bar = new JMenuBar();
    setJMenuBar( bar );
    bar.add( fileMenu );
    JMenu formatMenu = new JMenu( "Format" );
    formatMenu.setMnemonic( 'r' );
    String colors[] = { "Black", "Blue", "Red", "Green" };
    JMenu colorMenu = new JMenu( "Color" );
    colorMenu.setMnemonic( 'C' );
    colorItems = new JRadioButtonMenuItem[ colors.length ];
    colorGroup = new ButtonGroup();
    ItemHandler itemHandler = new ItemHandler();
    for ( int count = 0; count < colors.length; count++ ) {
      colorItems[ count ] =new JRadioButtonMenuItem( colors[ count ] );
      colorMenu.add( colorItems[ count ] );
      colorGroup.add( colorItems[ count ] );
      colorItems[ count ].addActionListener( itemHandler );
   }
   colorItems[ 0 ].setSelected( true );
   formatMenu.add( colorMenu );
   formatMenu.addSeparator();
   String fontNames[] = { "Serif", "Monospaced", "SansSerif" };
   JMenu fontMenu = new JMenu( "Font" );
   fontMenu.setMnemonic( 'n' );
   fonts = new JRadioButtonMenuItem[ fontNames.length ];
   fontGroup = new ButtonGroup();
   for ( int count = 0; count < fonts.length; count++ ) {
     fonts[ count ] = new JRadioButtonMenuItem( fontNames[ count ] );
     fontMenu.add( fonts[ count ] );
     fontGroup.add( fonts[ count ] );
     fonts[ count ].addActionListener( itemHandler );
   }
   fonts[ 0 ].setSelected( true );
   fontMenu.addSeparator();
   String styleNames[] = { "Bold", "Italic" };
   styleItems = new JCheckBoxMenuItem[ styleNames.length ];
   StyleHandler styleHandler = new StyleHandler();
   for ( int count = 0; count < styleNames.length; count++ ) {
     styleItems[ count ] = new JCheckBoxMenuItem( styleNames[ count ] );
     fontMenu.add( styleItems[ count ] );
     styleItems[ count ].addItemListener( styleHandler );
   }
   formatMenu.add( fontMenu );
   bar.add( formatMenu );
   displayLabel = new JLabel("注意字体和颜色变化", SwingConstants.CENTER );
   displayLabel.setForeground( colorValues[ 0 ] );
   displayLabel.setFont( new Font( "TimesRoman", Font.PLAIN, 40 ) );
   getContentPane().add( displayLabel, BorderLayout.CENTER );
   setSize( 500, 200 );
   setVisible( true );
  } // end constructor
 public static void main( String args[] ){
   MenuTest application = new MenuTest();
   application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
 }
 private class ItemHandler implements ActionListener {
   public void actionPerformed( ActionEvent event ) {
     for ( int count = 0; count < colorItems.length; count++ )
       if ( colorItems[ count ].isSelected() ) {
     displayLabel.setForeground( colorValues[ count ] );
     break;
       }
      for ( int count = 0; count < fonts.length; count++ )
        if ( event.getSource() == fonts[ count ] ) {
          displayLabel.setFont( new Font(fonts[ count ].getText(), style, 40 ) );
          break;
        }
       repaint();
  }
 } // end class ItemHandler
 private class StyleHandler implements ItemListener {
 public void itemStateChanged( ItemEvent e ){
   style = 0;
   if ( styleItems[ 0 ].isSelected() )
     style += Font.BOLD;
   if ( styleItems[ 1 ].isSelected() )
     style += Font.ITALIC;
   displayLabel.setFont( new Font(displayLabel.getFont().getName(), style, 40 ) );
   repaint();
   }
  }
}