menuexp.java

Java的swing的课堂练习。。 。

/**
 * @(#)MenuExp.java
 *
 *
 * @author 
 * @version 1.00 2007/11/5
 */
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;

   // set up GUI
   public MenuTest()
   {
      super( "Using JMenus" );     

      // set up File menu and its menu items
      JMenu fileMenu = new JMenu( "File" );
      fileMenu.setMnemonic( 'F' );

      // set up About... menu item
      JMenuItem aboutItem = new JMenuItem( "About..." );
      aboutItem.setMnemonic( 'A' );
      aboutItem.addActionListener(
         // anonymous inner class to handle menu item event
         new ActionListener() {
         // display message dialog when user selects About...
            public void actionPerformed( ActionEvent event )
            {
               JOptionPane.showMessageDialog( MenuTest.this,
                  "This is an example\nof using menus",
                  "About", JOptionPane.PLAIN_MESSAGE );
            }
         }  // end anonymous inner class
      ); // end call to addActionListener
 
      //attach aboutItem to fileMenu
      fileMenu.add( aboutItem );

      // set up Exit menu item
      JMenuItem exitItem = new JMenuItem( "Exit" );
      exitItem.setMnemonic( 'x' );
      exitItem.addActionListener(
         // anonymous inner class to handle exitItem event
         new ActionListener() {
            public void actionPerformed( ActionEvent event )
            {
               System.exit( 0 );
            }
         }  // end anonymous inner class
      ); // end call to addActionListener

      fileMenu.add( exitItem );

      // create menu bar and attach it to MenuTest window
      JMenuBar bar = new JMenuBar();  
      setJMenuBar( bar );  
      bar.add( fileMenu ); //add menu to bar

      // create Format menu, its submenus and menu items
      JMenu formatMenu = new JMenu( "Format" );  
      formatMenu.setMnemonic( 'r' );

      // create Color submenu
      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();

      // create color radio button menu items
      for ( int count = 0; count < colors.length; count++ ) {
         colorItems[ count ] = 
            new JRadioButtonMenuItem( colors[ count ] );

         colorMenu.add( colorItems[ count ] );
      //add these colorItems to the same ButtonGroup
         colorGroup.add( colorItems[ count ] );
         colorItems[ count ].addActionListener( itemHandler );
      }

      // select first Color menu item
      colorItems[ 0 ].setSelected( true );  

      // add format menu to menu bar
      formatMenu.add( colorMenu );
      formatMenu.addSeparator();

      // create Font submenu
      String fontNames[] = { "Serif", "Monospaced", "SansSerif" };

      JMenu fontMenu = new JMenu( "Font" );
      fontMenu.setMnemonic( 'n' );

      fonts = new JRadioButtonMenuItem[ fontNames.length ];
      fontGroup = new ButtonGroup();

      // create Font radio button menu items
      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 );
      }

      // select first Font menu item
      fonts[ 0 ].setSelected( true );

      fontMenu.addSeparator();

      // set up style menu items
      String styleNames[] = { "Bold", "Italic" };

      styleItems = new JCheckBoxMenuItem[ styleNames.length ];
      StyleHandler styleHandler = new StyleHandler();

      // create style checkbox menu items
      for ( int count = 0; count < styleNames.length; count++ ) {
         styleItems[ count ] = 
            new JCheckBoxMenuItem( styleNames[ count ] );

         fontMenu.add( styleItems[ count ] );

         styleItems[ count ].addItemListener( styleHandler );
      }

      // put Font menu in Format menu
      formatMenu.add( fontMenu );

      // add Format menu to menu bar
      bar.add( formatMenu );  
     
      // set up label to display text
      displayLabel = new JLabel( 
         "Sample Text", SwingConstants.CENTER );
      displayLabel.setForeground( colorValues[ 0 ] );
      displayLabel.setFont( 
         new Font( "TimesRoman", Font.PLAIN, 72 ) );

      getContentPane().setBackground( Color.cyan );
      getContentPane().add( displayLabel, BorderLayout.CENTER );

      setSize( 500, 200 );
      setVisible( true );

   }  // end constructor

   // execute application
   public static void main( String args[] )
   {
      MenuTest application = new MenuTest();

      application.setDefaultCloseOperation(
         JFrame.EXIT_ON_CLOSE );
   }

   // inner class to handle action events from menu items
   private class ItemHandler implements ActionListener {

      // process color and font selections
      public void actionPerformed( ActionEvent event )
      {
         // process color selection
         for ( int count = 0; count < colorItems.length; count++ )
  
            if ( colorItems[ count ].isSelected() ) {
               displayLabel.setForeground( colorValues[ count ] );
               break;
            }
 
         // process font selection
         for ( int count = 0; count < fonts.length; count++ )

            if ( event.getSource() == fonts[ count ] ) {
               displayLabel.setFont( new Font( 
                  fonts[ count ].getText(), style, 72 ) );
               break;
            }

         repaint();   
      }
   }  // end class ItemHandler

   // inner class to handle item events from check box menu items
   private class StyleHandler implements ItemListener {

      // process font style selections
      public void itemStateChanged( ItemEvent e )
      {
         style = 0;

         // check for bold selection
         if ( styleItems[ 0 ].isSelected() )
            style += Font.BOLD;

         // check for italic selection
         if ( styleItems[ 1 ].isSelected() )
            style += Font.ITALIC;

         displayLabel.setFont( new Font( 
            displayLabel.getFont().getName(), style, 72 ) );

         repaint();
      }
   }  // end class StyleHandler
}  // end class MenuTest