Create Animated GIF Field

AnimatedGIFField is a field that displays an animated GIF. This component can be added to any Blackberry screen where a animated GIF needs to be displayed. The animations needed for the particular GIF will be calculated by the component and is displayed with appropriate animations.

import net.rim.device.api.system.GIFEncodedImage;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.BitmapField;

public class AnimatedGIFField extends BitmapField 
{
 //The image to draw.
 private GIFEncodedImage _image;  
 //The current frame in the animation sequence.
 private int _currentFrame;          
 private AnimatorThread _animatorThread;


 /**
  * Constructs a new AnimatedGIFField instance with provided image
  * @param image instance of GIFEncodedImage 
  */
 public AnimatedGIFField(GIFEncodedImage image)
 {
  this(image, 0);
 }


 /**
  * Constructs a new AnimatedGIFField instance with provided image
  * @param image instance of GIFEncodedImage 
  * @param style long to represent the style 
  */
 public AnimatedGIFField(GIFEncodedImage image, long style)
 {
  //Call super to setup the field with the specified style.
  //The image is passed in as well for the field to configure its required size.
  super(image.getBitmap(), style);

  //Store the image and it's dimensions.
  this._image = image;

  //Start the animation thread.
  _animatorThread = new AnimatorThread(this);
  _animatorThread.start();
 }

 protected void paint(Graphics graphics)
 {
  //Call super.paint.  This will draw the first background frame and handle any required focus drawing.
  super.paint(graphics);

  //Don't redraw the background if this is the first frame.
  if (_currentFrame != 0)
  {
   //Draw the animation frame.
   graphics.drawImage(_image.getFrameLeft(_currentFrame), _image.getFrameTop(_currentFrame), 
     _image.getFrameWidth(_currentFrame), _image.getFrameHeight(_currentFrame), _image, _currentFrame, 0, 0);
  }
 }

 //Stop the animation thread when the screen the field is on is
 //popped off of the display stack.
 protected void onUndisplay()
 {
  _animatorThread.stop();
  super.onUndisplay();
 }


 //A thread to handle the animation.
 private class AnimatorThread extends Thread
 {
  private AnimatedGIFField _theField;
  private boolean _keepGoing = true;      
  private int _totalFrames;               //The total number of frames in the image.
  private int _loopCount;                 //The number of times the animation has looped (completed).
  private int _totalLoops;                //The number of times the animation should loop (set in the image).

  /**
   * Constructor of Animator Thread
   * @param theField field to animate
   */
  public AnimatorThread(AnimatedGIFField theField)
  {
   this._theField = theField;
   _totalFrames = _image.getFrameCount();
   _totalLoops = _image.getIterations();

  }
  /**
   * Method to stop the animation thread
   */
  public synchronized void stop()
  {
   _keepGoing = false;
  }

  public void run()
  {
   while(_keepGoing)
   {
    //Invalidate the field so that it is redrawn.
    UiApplication.getUiApplication().invokeAndWait(new Runnable() 
    {
     public void run() 
     {
      _theField.invalidate();      
     }
    });                

    try
    {
     //Sleep for the current frame delay before the next frame is drawn.
     sleep(_image.getFrameDelay(_currentFrame) * 10);
    }
    catch (InterruptedException iex)
    {} //Couldn't sleep.

    //Increment the frame.
    ++_currentFrame;      

    if (_currentFrame == _totalFrames)
    {
     //Reset back to frame 0 if we have reached the end.
     _currentFrame = 0;

     ++_loopCount;

     //Check if the animation should continue.
     if (_loopCount == _totalLoops)
     {
      _keepGoing = false;
     }
    }
   }
  }
 }
}