J2ME Animation using repaint( ) method

In this part of J2ME Image Tutorial, we are going to show you how to create an Image with animation. Here we have create a class called ImageAanimation that extends MIDlet and implements the CommandListner class. We have also used the predefined Canvas class to show the animation and image. For this, we have created a ImageCanvas2 class that extends the Canvas class to draw the animation and blink the image for a given period of time. To draw the image we are using the following methods:

image = Image.createImage("/cartoondog.png");
frame_width = image.getWidth();
frame_height = image.getHeight();

And when image created then we can appear this image using this methods:

while(run_thread){

   Thread.sleep((frame_index == Frame_Count - 1) ? 

         Last_Frame_Count : Frame_Hold);

   int last_frame_index = frame_index;

   frame_index = (frame_index + 1) % Frame_Count;

   int repaint_left = position[last_frame_index];

   int repaint_right = position[frame_index];

    

   if(position[last_frame_index] > position[frame_index]){

     repaint_left = position[frame_index];

     repaint_right = position[last_frame_index];

   }

   repaint_left = (repaint_left * run_length) >> 10;

   repaint_right = (repaint_right * run_length) >> 10;

   repaint(repaint_left, 0, frame_width + repaint_right - 

         repaint_left, frame_height);

      }

The Application is as follows:

Source Code ImageAnimation.java


import javax.microedition.midlet.*;

import javax.microedition.lcdui.*;



public class ImageAnimation extends MIDlet implements CommandListener{

  private Display  display;

  private Command exit;

  

  protected void startApp(){

    display = Display.getDisplay(this);

    ImageCanvas2 canvas = new ImageCanvas2();

    exit = new Command("Exit", Command.EXIT, 1);

        canvas.addCommand(exit);

        canvas.setCommandListener(this);

        display.setCurrent(canvas);

    }

    

    protected void pauseApp(){}

    

    protected void destroyApp(boolean unconditional){

    notifyDestroyed();

  }

    

    public void commandAction(Command c, Displayable d){

    String label = c.getLabel();

    if(label.equals("Exit")) {

      destroyApp(true);

    }

  }

}



class ImageCanvas2 extends Canvas implements Runnable{

  int Frame_Count = 17;

  int Frame_Hold = 70000;

  int Last_Frame_Count = 300;

  int[] position = {

    0, 50, 186, 372, 558, 744, 930, 1024, 1024,

    834, 651, 465, 279, 93, 0, 0, 0};

  

  private Image image;

  int frame_width = 0;

  int frame_height = 0;

  int frame_index = 0;

  int run_length = 0;

  boolean run_thread = false;



  protected void showNotify(){

    try{

      image = Image.createImage("/cartoondog.png");

      frame_width = image.getWidth();

      frame_height = image.getHeight();

    } catch (Exception ioe) {

      return;

    }

    run_length = getWidth() - frame_width;

    run_thread = true;

    frame_index = 0;

    new Thread(this).start();

  }



  protected void hideNotify(){

    run_thread = false;

  }



  public void run(){

    try{

      while(run_thread){

        Thread.sleep((frame_index == Frame_Count - 1) ? 

        Last_Frame_Count : Frame_Hold);

        int last_frame_index = frame_index;

        frame_index = (frame_index + 1) % Frame_Count;

        int repaint_left = position[last_frame_index];

        int repaint_right = position[frame_index];

        

        if(position[last_frame_index] > position[frame_index]){

          repaint_left = position[frame_index];

          repaint_right = position[last_frame_index];

        }

        repaint_left = (repaint_left * run_length) >> 10;

        repaint_right = (repaint_right * run_length) >> 10;

        repaint(repaint_left, 0, frame_width + repaint_right - 

        repaint_left, frame_height);

      }

    }catch(Exception e){}

  }



  public void paint(Graphics g){

    g.setColor(0, 0, 255);

    g.fillRect(0, 0, getWidth(), getHeight());

    g.translate((position[frame_index] * run_length) >> 10, 0);

    g.clipRect(0, 0, frame_width, frame_height);

    g.drawImage(image, 0, -(frame_index * frame_height), 

    Graphics.LEFT + Graphics.TOP);

  }

}

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