@Override public int getItemCount() {
    int size = items.size();
    if (hasHeader()) {
      size++;
    }
    if (hasFooter()) {
      size++;
    }
    return size;
  }
@ Override public int getItemCount ( ) { int size = items . size ( ) ; if ( hasHeader ( ) ) { size ++ ; } if ( hasFooter ( ) ) { size ++ ; } return size ; }
Returns the items list size if there is no a header configured or the size taking into account
that if a header or a footer is configured the number of items returned is going to include
this elements.