Only change the code in onCreate() of AndroidViewUI.java
package com.exercise.AndroidViewUI;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
public class AndroidViewUI extends Activity {
    public class MyView extends View {
     private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
     
     private float initX, initY, radius;  
     private boolean drawing = false;  
     
  public MyView(Context context) {
   super(context);
   // TODO Auto-generated constructor stub
   init();
  }
  public MyView(Context context, AttributeSet attrs) {
   super(context, attrs);
   // TODO Auto-generated constructor stub
   init();
  }
  public MyView(Context context, AttributeSet attrs, int defStyle) {
   super(context, attrs, defStyle);
   // TODO Auto-generated constructor stub
   init();
  }
  
  private void init(){
   paint.setStyle(Paint.Style.STROKE);
   paint.setStrokeWidth(3);  
   paint.setColor(Color.WHITE);  
  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
   // TODO Auto-generated method stub
   setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), 
     MeasureSpec.getSize(heightMeasureSpec));
  }
  @Override
  protected void onDraw(Canvas canvas) {
   // TODO Auto-generated method stub
   if(drawing){
    canvas.drawCircle(initX, initY, radius, paint);
   }
  }
  @Override
  public boolean onTouchEvent(MotionEvent event) {
   // TODO Auto-generated method stub
   
   int action = event.getAction();
   if (action==MotionEvent.ACTION_MOVE){
    float x = event.getX();
    float y = event.getY();
    
    radius = (float) Math.sqrt(Math.pow(x-initX, 2) + Math.pow(y-initY, 2));
    
   }
   else if (action==MotionEvent.ACTION_DOWN){
    initX = event.getX();
    initY = event.getY();
    radius = 1;
    drawing = true; 
   }
   else if (action==MotionEvent.ACTION_UP){
    drawing = false; 
   }
   invalidate();
   return true;
  }
 }
 
 /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        
        LinearLayout mainLayout = new LinearLayout(this);
        mainLayout.setOrientation(LinearLayout.VERTICAL);
       
        MyView myView1 = new MyView(this);
        LayoutParams myView1Params =  new LayoutParams(200, 200);
        myView1.setLayoutParams(myView1Params);
        myView1.setBackgroundColor(Color.GREEN);
        
        MyView myView2 = new MyView(this);
        LayoutParams myView2Params =  new LayoutParams(300, 200);
        myView2.setLayoutParams(myView2Params);
        myView2.setBackgroundColor(Color.BLUE);
        
        mainLayout.addView(myView1);
        mainLayout.addView(myView2);
        setContentView(mainLayout);    
    }   
}