imageanimationusingmediatracker.java

此源码为机械工业出版社出版的《Java语言程序设计》第三版所配套的书中所有源代码。

// ImageAnimationUsingMediaTracker.java: Monitor loading images
// using MediaTracker 
import java.awt.*;
import javax.swing.*;

public class ImageAnimationUsingMediaTracker extends ImageAnimation
{
  private MediaTracker imageTracker = new MediaTracker(this);

  // Initialize the applet
  public void init()
  {
    // Load the image, the image files are named
    // L1 - L52 in Images directory
    imageArray = new Image[numOfImages];
    for (int i=0; i<imageArray.length; i++ )
    {
      imageArray[i] = getImage(getDocumentBase(),
        "Images/L" + (i+1) + ".gif" );

      // Register images with the imageTracker
      imageTracker.addImage(imageArray[i], i);
    }

    // Wait for all the images to be completely loaded
    try
    {
      imageTracker.waitForAll();
    }
    catch (InterruptedException ex)
    {
      System.out.println(ex);
    }

    // Dispose of imageTracker since it is no longer needed
    imageTracker = null;

    // Panel p to hold animation control
    JPanel p = new JPanel();
    p.setLayout(new BorderLayout());
    p.add(new JLabel("Animation speed in millisecond"),
      BorderLayout.WEST);
    p.add(jtfSpeed, BorderLayout.CENTER);
    p.add(jbtReverse, BorderLayout.EAST);

    // Add the image panel and p to the applet
    getContentPane().add(new PlayImage(), BorderLayout.CENTER);
    getContentPane().add(p, BorderLayout.SOUTH);

    // Register listener
    jtfSpeed.addActionListener(this);
    jbtReverse.addActionListener(this);
  }
}