private void notifyChange(int previous,int current){
  if (mOnValueChangeListener != null) {
    mOnValueChangeListener.onValueChange(this,previous,mValue);
  }
}

private void notifyChange ( int previous , int current ) { if ( mOnValueChangeListener != null ) { mOnValueChangeListener . onValueChange ( this , previous , mValue ) ; } }
notifies the listener , if registered , of a change of the value of this numberpicker .
