imagealbum.java

来自「32个java程序源代码」· Java 代码 · 共 220 行

// Exercise 25.12: ImageAlbum.java
// This application uses file processing to implement an image album
// with image having its own text description.
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;

public class ImageAlbum extends JFrame
{
   // JLabel to show current book
   private JLabel mainJLabel;

   // JTextArea and JScrollPane to display information on a book
   private JTextArea descriptionJTextArea;
   private JScrollPane descriptionJScrollPane;

   // JLabel and JButton to allow user to got to the previous book 
   private JLabel previousJLabel;
   private JButton previousJButton;

   // JLabel and JButton to allow user to got to the next book 
   private JLabel nextJLabel;
   private JButton nextJButton;
   
   // represents current image's index
   private int current = 0;
   
   private String largeImage[] = new String[ 6 ];
   private String smallImage[] = new String[ 6 ];
   private String descriptions[] = new String[ 6 ];

   // no-argument constructor
   public ImageAlbum() 
   {
      createUserInterface();
   }
   
   // create and position GUI components; register event handlers
   private void createUserInterface()
   {
      // get content pane for attaching GUI components
      Container contentPane = getContentPane();
      
      // enable explicit positioning of GUI components
      contentPane.setLayout( null );

      // set up mainJLabel
      mainJLabel = new JLabel();
      mainJLabel.setBounds( 16, 16, 273, 357 );
      mainJLabel.setEnabled( true );
      contentPane.add( mainJLabel );

      // set up descriptionJTextArea
      descriptionJTextArea = new JTextArea();
      descriptionJScrollPane = new JScrollPane( 
         descriptionJTextArea );
      descriptionJScrollPane.setBounds( 16, 392, 272, 48 );
      descriptionJScrollPane.setVerticalScrollBarPolicy( 
         JScrollPane.VERTICAL_SCROLLBAR_ALWAYS );
      descriptionJTextArea.setLineWrap( true );
      descriptionJTextArea.setWrapStyleWord( true );
      descriptionJTextArea.setEditable( false );
      contentPane.add( descriptionJScrollPane );

      // set up previousJButton
      previousJButton = new JButton();
      previousJButton.setBounds( 307, 144, 123, 23 );
      previousJButton.setText( "Previous Image" );
      contentPane.add( previousJButton );
      previousJButton.addActionListener(

         new ActionListener() // anonymous inner class
         {
            // event handler called when previousJButton is clicked
            public void actionPerformed( ActionEvent event )
            {
               previousJButtonActionPerformed( event );
            }

         } // end anonymous inner class

      ); // end call to addActionListener

      // set up previousJLabel
      previousJLabel = new JLabel();
      previousJLabel.setBounds( 323, 16, 91, 119 );
      contentPane.add( previousJLabel );

      // set up nextJButton
      nextJButton = new JButton();
      nextJButton.setBounds( 307, 352, 123, 23 );
      nextJButton.setText( "Next Image" );
      contentPane.add( nextJButton );
      nextJButton.addActionListener(

         new ActionListener() // anonymous inner class
         {
            // event handler called when nextJButton is clicked
            public void actionPerformed( ActionEvent event )
            {
               nextJButtonActionPerformed( event );
            }

         } // end anonymous inner class

      ); // end call to addActionListener

      // set up nextJLabel
      nextJLabel = new JLabel();
      nextJLabel.setBounds( 323, 224, 91, 119 );
      contentPane.add( nextJLabel );
      
      // set properties of application's window
      setTitle( "Image Album" ); // set title bar string
      setSize( 447, 480 );       // set window size
      setVisible( true );        // display window

      displayImage(); // display first image at start

   } // end method createUserInterface

   // extract descriptions from file and images from the directory
   private void retrieveData()
   {

   } // end method retrieveData

   // display images in JLabels
   private void displayImage()
   {
      // set main image
      mainJLabel.setIcon( new ImageIcon( largeImage[ current ] ) );
      
      // if index is 0 (first image), do not show previous image
      if ( current == 0 )
      {
         // disable previous image
         previousJLabel.setVisible( false );

         // preview next image
         nextJLabel.setIcon( new ImageIcon( 
            smallImage[ current + 1 ] ) );

         // disable previousJButton
		 previousJButton.setEnabled( false );
      }

      // if index corresponds to last item in array,
      // do not show next image
      else if ( current == ( largeImage.length - 1 ) )
      {
         previousJLabel.setIcon( new ImageIcon( 
            smallImage[ current - 1 ] ) );

         nextJLabel.setVisible( false );  // disable next image
         nextJButton.setEnabled( false ); // disable nextJButton
      }

      // show previous, current and next image
      else
      {
         previousJLabel.setVisible( true );
         previousJLabel.setIcon( new ImageIcon( 
            smallImage[ current - 1 ] ) );

         nextJLabel.setVisible( true );
         nextJLabel.setIcon( new ImageIcon( 
            smallImage[ current + 1 ] ) );

         // enable JButtons
         previousJButton.setEnabled( true );
         nextJButton.setEnabled( true );
      }

      // set description
      descriptionJTextArea.setText( descriptions[ current ] );

   } // end method displayImage

   // display previous image
   private void previousJButtonActionPerformed( ActionEvent event )
   {
      current--;
      displayImage(); // display new images

   } // end method previousJButtonActionPerformed

   // display next image
   private void nextJButtonActionPerformed( ActionEvent event )
   {
      current++;
      displayImage(); // display new images

   } // end method nextJButtonActionPerformed

   // main method
   public static void main( String args[] ) 
   {
      ImageAlbum application = new ImageAlbum();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

   } // end method main

} // end class ImageAlbum

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 * (C) Copyright 1992-2004 by Deitel & Associates, Inc. and               *
 * Pearson Education, Inc. All Rights Reserved.                           *
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