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# spreadsheetitem.cpp Example File

demos/spreadsheet/spreadsheetitem.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
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     ** This file is part of the demonstration applications of the Qt Toolkit.
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     ** Alternatively, this file may be used under the terms of the GNU Lesser
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     ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
     ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
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     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License version 3.0 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.GPL included in the
     ** packaging of this file.  Please review the following information to
     ** ensure the GNU General Public License version 3.0 requirements will be
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     #include "spreadsheetitem.h"

     SpreadSheetItem::SpreadSheetItem()
             : QTableWidgetItem(), isResolving(false)
     {
     }

     SpreadSheetItem::SpreadSheetItem(const QString &text)
             : QTableWidgetItem(text), isResolving(false)
     {
     }

     QTableWidgetItem *SpreadSheetItem::clone() const
     {
         SpreadSheetItem *item = new SpreadSheetItem();
         *item = *this;
         return item;
     }

     QVariant SpreadSheetItem::data(int role) const
     {
         if (role == Qt::EditRole || role == Qt::StatusTipRole)
             return formula();

         if (role == Qt::DisplayRole)
             return display();

         QString t = display().toString();
         bool isNumber = false;
         int number = t.toInt(&isNumber);

         if (role == Qt::TextColorRole) {
             if (!isNumber)
                 return QVariant::fromValue(QColor(Qt::black));
             else if (number < 0)
                 return QVariant::fromValue(QColor(Qt::red));
             return QVariant::fromValue(QColor(Qt::blue));
         }

          if (role == Qt::TextAlignmentRole)
              if (!t.isEmpty() && (t.at(0).isNumber() || t.at(0) == '-'))
                  return (int)(Qt::AlignRight | Qt::AlignVCenter);

          return QTableWidgetItem::data(role);
      }

     void SpreadSheetItem::setData(int role, const QVariant &value)
     {
         QTableWidgetItem::setData(role, value);
         if (tableWidget())
             tableWidget()->viewport()->update();
     }

     QVariant SpreadSheetItem::display() const
     {
         // avoid circular dependencies
         if (isResolving)
             return QVariant();

         isResolving = true;
         QVariant result = computeFormula(formula(), tableWidget(), this);
         isResolving = false;
         return result;
     }

     QVariant SpreadSheetItem::computeFormula(const QString &formula,
                                              const QTableWidget *widget,
                                              const QTableWidgetItem *self)
     {
         // check if the s tring is actually a formula or not
         QStringList list = formula.split(' ');
         if (list.isEmpty() || !widget)
             return formula; // it is a normal string

         QString op = list.value(0).toLower();

         int firstRow = -1;
         int firstCol = -1;
         int secondRow = -1;
         int secondCol = -1;

         if (list.count() > 1)
             decode_pos(list.value(1), &firstRow, &firstCol);

         if (list.count() > 2)
             decode_pos(list.value(2), &secondRow, &secondCol);

         const QTableWidgetItem *start = widget->item(firstRow, firstCol);
         const QTableWidgetItem *end = widget->item(secondRow, secondCol);

         int firstVal = start ? start->text().toInt() : 0;
         int secondVal = end ? end->text().toInt() : 0;

         QVariant result;
         if (op == "sum") {
             int sum = 0;
             for (int r = firstRow; r <= secondRow; ++r) {
                 for (int c = firstCol; c <= secondCol; ++c) {
                     const QTableWidgetItem *tableItem = widget->item(r, c);
                     if (tableItem && tableItem != self)
                         sum += tableItem->text().toInt();
                 }
             }

             result = sum;
         } else if (op == "+") {
             result = (firstVal + secondVal);
         } else if (op == "-") {
             result = (firstVal - secondVal);
         } else if (op == "*") {
             result = (firstVal * secondVal);
         } else if (op == "/") {
             if (secondVal == 0)
                 result = QString("nan");
             else
                 result = (firstVal / secondVal);
         } else if (op == "=") {
             if (start)
                 result = start->text();
         } else {
             result = formula;
         }

         return result;
     }