ArryOutOfBoundsException when Dragging and Droping of a bitmap on a canvas
<p>I have a problem that I implemented a functionality in which we draw bitmaps on a canvas and We can Dragging and dropping the same in whole canvas area, I refer the Drag and Drop Sample Code from the API Demos which is working fine but when we implement same functionality in our code then it returns ArrrayOutOfBoundsException frequently means some times it is working fine and some times returns an error after touching the Canvas. Please suggest me a right solution for the problem if you find any bug in the source.</p>

<p><strong>Error Stack:</strong></p>

<pre><code>02-27 11:41:16.046: E/AndroidRuntime(5413): FATAL EXCEPTION: main
02-27 11:41:16.046: E/AndroidRuntime(5413): java.lang.ArrayIndexOutOfBoundsException
02-27 11:41:16.046: E/AndroidRuntime(5413):     at com.TestFace.FaceDetect.DrawView.onTouchEvent(DrawView.java:132)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.view.View.dispatchTouchEvent(View.java:3766)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1676)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1112)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.app.Activity.dispatchTouchEvent(Activity.java:2086)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1660)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1785)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.os.Looper.loop(Looper.java:123)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at android.app.ActivityThread.main(ActivityThread.java:4627)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at java.lang.reflect.Method.invokeNative(Native Method)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at java.lang.reflect.Method.invoke(Method.java:521)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
02-27 11:41:16.046: E/AndroidRuntime(5413):     at dalvik.system.NativeStart.main(Native Method)
</code></pre>

<p><strong>DrawView.java:</strong></p>

<p>package com.TestFace.FaceDetect;</p>

<pre><code>import java.io.IOException;
import java.net.MalformedURLException;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Point;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.view.MotionEvent;
import android.view.View;

import com.TestFace.FaceDetect.Util.ResultPack;

public class DrawView extends View {
   private ColorBall[] colorballs = new ColorBall[3]; // array that holds the balls
   private int balID = 0; // variable to know what ball is being dragged
   ResultPack result = ResultPack.getSingletonObject();
   Bitmap myBitmap,myBitmap_Circle;
   int width, height;
    public DrawView(Context context) {
        super(context);
        setFocusable(true); //necessary for getting the touch events

        // setting the start point for the balls
        Point point1 = new Point();
        point1.x = (int)result.getEyeLeftX()+50;
        point1.y = (int)result.getEyeLeftY()+25;
        Point point2 = new Point();
        point2.x = (int)result.getEyeRightX()+50;
        point2.y = (int)result.getEyeRightY()+25;
        Point point3 = new Point();
        point3.x = (int)result.getMouthCenterX()+50;
        point3.y = (int)result.getMouthCenterY()+25;

        Drawable d=null;
        try {
            d = drawable_from_url(result.getImgUrl(), "Image Url");
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  

        myBitmap=((BitmapDrawable)d).getBitmap();
        myBitmap_Circle = BitmapFactory.decodeResource(getResources(), R.drawable.circle1);
         // declare each ball with the ColorBall class
        colorballs[0] = new ColorBall(context,myBitmap_Circle, point1);
        colorballs[1] = new ColorBall(context,myBitmap_Circle, point2);
        colorballs[2] = new ColorBall(context,myBitmap_Circle, point3);
        width=myBitmap.getWidth();
        height=myBitmap.getHeight();


    }

    Drawable drawable_from_url(String url, String src_name) throws java.net.MalformedURLException, java.io.IOException 
    {
        return Drawable.createFromStream(((java.io.InputStream)new java.net.URL(url).getContent()), src_name);
    }

    // the method that draws the balls
    @Override protected void onDraw(Canvas canvas) {
        //canvas.drawColor(0xFFCCCCCC);     //if you want another background color       
        canvas.drawBitmap(myBitmap, 0,0, null);
        //draw the balls on the canvas
        for (ColorBall ball : colorballs) {
            canvas.drawBitmap(ball.getBitmap(), ball.getX(), ball.getY(), null);
          }
    }

    // events when touching the screen
    public boolean onTouchEvent(MotionEvent event) {
        int eventaction = event.getAction(); 

        int X = (int)event.getX(); 
        int Y = (int)event.getY(); 

        switch (eventaction ) { 

        case MotionEvent.ACTION_DOWN: // touch down so check if the finger is on a ball
            balID = 0;
            for (int i=0;i&lt;colorballs.length;i++) {
                // check if inside the bounds of the ball (circle)
                // get the center for the ball
                int centerX = colorballs[i].getX() + 25;
                int centerY = colorballs[i].getY() + 25;

                // calculate the radius from the touch to the center of the ball
                double radCircle  = Math.sqrt( (double) (((centerX-X)*(centerX-X)) + (centerY-Y)*(centerY-Y)));
                System.out.println("The Rad Circle:"+radCircle);
                // if the radius is smaller then 23 (radius of a ball is 22), then it must be on the ball
                if (radCircle &lt; 23){

                    balID = colorballs[i].getID();

                }

                // check all the bounds of the ball (square)
                //if (X &gt; ball.getX() &amp;&amp; X &lt; ball.getX()+50 &amp;&amp; Y &gt; ball.getY() &amp;&amp; Y &lt; ball.getY()+50){
                //  balID = ball.getID();
                //  break;
                //}
              }

             break; 


        case MotionEvent.ACTION_MOVE:   // touch drag with the ball
            // move the balls the same as the finger
            if (balID &gt; 0) {
                colorballs[balID-1].setX(X-25);
                colorballs[balID-1].setY(Y-25);
            }

            break; 

        case MotionEvent.ACTION_UP: 
            // touch drop - just do things here after dropping

             break; 
        } 
        // redraw the canvas
        invalidate(); 
        return true; 

    }
}
</code></pre>

<p><strong>ColorBall.java:</strong></p>

<pre><code>package com.TestFace.FaceDetect;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;

public class ColorBall  {
 private Bitmap img; // the image of the ball
 private int coordX = 0; // the x coordinate at the canvas
 private int coordY = 0; // the y coordinate at the canvas
 private int id; // gives every ball his own id, for now not necessary
 private static int count = 1;
 private boolean goRight = true;
 private boolean goDown = true;

    public ColorBall(Context context, Bitmap drawable) {

        BitmapFactory.Options opts = new BitmapFactory.Options();
        opts.inJustDecodeBounds = true;
        //img = BitmapFactory.decodeResource(context.getResources(), drawable);
        img = drawable;
        id=count;
        count++;
    }

    public ColorBall(Context context, Bitmap drawable, Point point) {

        BitmapFactory.Options opts = new BitmapFactory.Options();
        opts.inJustDecodeBounds = true;
        //img = BitmapFactory.decodeResource(context.getResources(), drawable);
        img = drawable;
        id=count;
        count++;
        coordX= point.x;
        coordY = point.y;

    }

    public static int getCount() {
        return count;
    }

    void setX(int newValue) {
        coordX = newValue;
    }

    public int getX() {
        return coordX;
    }

    void setY(int newValue) {
        coordY = newValue;
   }

    public int getY() {
        return coordY;
    }

    public int getID() {
        return id;
    }

    public Bitmap getBitmap() {
        return img;
    }

    public void moveBall(int goX, int goY) {
        // check the borders, and set the direction if a border has reached
        if (coordX &gt; 270){
            goRight = false;
        }
        if (coordX &lt; 0){
            goRight = true;
        }
        if (coordY &gt; 400){
            goDown = false;
        }
        if (coordY &lt; 0){
            goDown = true;
        }
        // move the x and y 
        if (goRight){
            coordX += goX;
        }else
        {
            coordX -= goX;
        }
        if (goDown){
            coordY += goY;
        }else
        {
            coordY -= goY;
        }

    }

}
</code></pre>
