logoanimator.java

java 编程源代码

// Fig. 6.34: LogoAnimator.java
// LogoAnimator is a JavaBean containing an animated logo.
package com.deitel.advjhtp1.beans;

// Java core packages
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

// Java extension packages
import javax.swing.*;

public class LogoAnimator extends JPanel 
   implements ActionListener, Serializable {

   protected ImageIcon images[];
   protected int totalImages = 30, currentImage;
   protected Timer animationTimer;

   // load images and start animation
   public LogoAnimator()
   {
      images = new ImageIcon[ totalImages ];

      URL url;

      // load animation frames
      for ( int i = 0; i < images.length; ++i ) {
         url = LogoAnimator.class.getResource( 
            "images/deitel" + i + ".png" );
         images[ i ] = new ImageIcon( url );
      }

      startAnimation();
   }

   // render one frame of the animation
   public void paintComponent( Graphics g )
   {
      super.paintComponent( g );

      // draw current animation frame
      images[ currentImage ].paintIcon( this, g, 0, 0 );
      currentImage = ( currentImage + 1 ) % totalImages;
   }

   // start Timer that drives animation
   public void startAnimation()
   {
      // if animationTimer is null, restart animation
      if ( animationTimer == null ) {
         currentImage = 0;  
         animationTimer = new Timer( 50, this );
         animationTimer.start();
      }
      
      else  // continue from last image displayed

         if ( !animationTimer.isRunning() )
            animationTimer.restart();
   }

   // repaint when Timer event occurs
   public void actionPerformed( ActionEvent actionEvent )
   {
      repaint();
   }

   // stop Timer that drives animation
   public void stopAnimation()
   {
      animationTimer.stop();
   }

   // get animation preferred width and height
   public Dimension getPreferredSize()
   {
      return new Dimension( 160, 80 );
   }

   // get animation minimum width and height
   public Dimension getMinimumSize()
   { 
      return getPreferredSize(); 
   }

   // execute bean as standalone application
   public static void main( String args[] )
   {
      // create new LogoAnimator
      LogoAnimator animation = new LogoAnimator();

      // create new JFrame with title "Animation test" 
      JFrame application = new JFrame( "Animator test" );
      application.setDefaultCloseOperation( 
         JFrame.EXIT_ON_CLOSE );

      // add LogoAnimator to JFrame
      application.getContentPane().add( animation,
         BorderLayout.CENTER );

      // set the window size and validate layout
      application.pack();
      application.setVisible( true );
   }

}  // end class LogoAnimator

/***************************************************************
 * (C) Copyright 2002 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.                                             *
 ***************************************************************/