private void updateSliderState(int touchX,int touchY){
  int distanceX=touchX - mCircleCenterX;
  int distanceY=mCircleCenterY - touchY;
  double c=Math.sqrt(Math.pow(distanceX,2) + Math.pow(distanceY,2));
  mAngle=Math.acos(distanceX / c);
  if (distanceY < 0) {
    mAngle=-mAngle;
  }
  if (mListener != null) {
    mListener.onSliderMoved((mAngle - mStartAngle) / (2 * Math.PI));
  }
}

private void updateSliderState ( int touchX , int touchY ) { int distanceX = touchX - mCircleCenterX ; int distanceY = mCircleCenterY - touchY ; double c = Math . sqrt ( Math . pow ( distanceX , 2 ) + Math . pow ( distanceY , 2 ) ) ; mAngle = Math . acos ( distanceX / c ) ; if ( distanceY < 0 ) { mAngle = - mAngle ; } if ( mListener != null ) { mListener . onSliderMoved ( ( mAngle - mStartAngle ) / ( 2 * Math . PI ) ) ; } }
invoked when slider starts moving or is currently moving . this method calculates and sets position and angle of the thumb .
