Initially I was trying to implement some functionality with which I could drow something touching the screen. Following code helped me i that case.
@Override
public boolean onTouchEvent(MotionEvent event) {
currentXCoordinate = event.getX();
currentYCoordinate = event.getY();
float radious = (float) 30.0;
canvas.drawCircle(currentXCoordinate, currentYCoordinate, radious, paint);
LinearLayout l1 = (LinearLayout)findViewById(R.id.drawarea);
l1.setBackgroundDrawable(new BitmapDrawable(myBitMap));
return super.onTouchEvent(event);
}