logoanimator.java

来自「经典的<<C how to program>一书第三版的例程。」· Java 代码 · 共 110 行

// Fig. 30.3: LogoAnimator.java
// Animation a series of images
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class LogoAnimator extends JPanel
                          implements ActionListener {
   protected ImageIcon images[];
   protected int totalImages = 30,
                 currentImage = 0,
                 animationDelay = 50; // 50 millisecond delay
   protected Timer animationTimer;

   public LogoAnimator()
   {
      setSize( getPreferredSize() );

      images = new ImageIcon[ totalImages ];

      for ( int i = 0; i < images.length; ++i ) 
         images[ i ] =
            new ImageIcon( "images/deitel" + i + ".gif" );

      startAnimation();
   }

   public void paintComponent( Graphics g )
   {
      super.paintComponent( g );

      if ( images[ currentImage ].getImageLoadStatus() ==
           MediaTracker.COMPLETE ) {
         images[ currentImage ].paintIcon( this, g, 0, 0 );
         currentImage = ( currentImage + 1 ) % totalImages;
      }
   }

   public void actionPerformed( ActionEvent e )
   {
      repaint();
   }

   public void startAnimation()
   {
      if ( animationTimer == null ) {
         currentImage = 0;  
         animationTimer = new Timer( animationDelay, this );
         animationTimer.start();
      }
      else  // continue from last image displayed
         if ( ! animationTimer.isRunning() )
            animationTimer.restart();
   }

   public void stopAnimation()
   {
      animationTimer.stop();
   }

   public Dimension getMinimumSize()
   { 
      return getPreferredSize(); 
   }

   public Dimension getPreferredSize()
   {
      return new Dimension( 160, 80 );
   }

   public static void main( String args[] )
   {
      LogoAnimator anim = new LogoAnimator();

      JFrame app = new JFrame( "Animator test" );
      app.getContentPane().add( anim, BorderLayout.CENTER );

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

      // The constants 10 and 30 are used below to size the
      // window 10 pixels wider than the animation and
      // 30 pixels taller than the animation. 
      app.setSize( anim.getPreferredSize().width + 10,
                   anim.getPreferredSize().height + 30 );
      app.show();
   }
}

/**************************************************************************
 * (C) Copyright 2000 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 *************************************************************************/