currencymodel.cpp

Qt4的一些例子

#include <QtCore>

#include "currencymodel.h"

CurrencyModel::CurrencyModel(QObject *parent)
    : QAbstractTableModel(parent)
{
}

void CurrencyModel::setCurrencyMap(const QMap<QString, double> &map)
{
    currencyMap = map;
    reset();
}

int CurrencyModel::rowCount(const QModelIndex & /* parent */) const
{
    return currencyMap.count();
}

int CurrencyModel::columnCount(const QModelIndex & /* parent */) const
{
    return currencyMap.count();
}

QVariant CurrencyModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();

    if (role == Qt::TextAlignmentRole) {
        return int(Qt::AlignRight | Qt::AlignVCenter);
    } else if (role == Qt::DisplayRole) {
        QString rowCurrency = currencyAt(index.row());
        QString columnCurrency = currencyAt(index.column());

        if (currencyMap.value(rowCurrency) == 0.0)
            return "####";

        double amount = currencyMap.value(columnCurrency)
                        / currencyMap.value(rowCurrency);

        return QString("%1").arg(amount, 0, 'f', 4);
    }
    return QVariant();
}

QVariant CurrencyModel::headerData(int section,
                                   Qt::Orientation /* orientation */,
                                   int role) const
{
    if (role != Qt::DisplayRole)
        return QVariant();
    return currencyAt(section);
}

QString CurrencyModel::currencyAt(int offset) const
{
    return (currencyMap.begin() + offset).key();
}