Subclassing QAbstractTableModel - Data from QSqlQuery

[cevou]

Hi,

I want to create a model that not only displays the data from an QSqlQuery but also changes the fields background-color. The color is passed by another query.

I tried to do that by subclassing QAbstractTableModel.

Here is my Code

#ifndef MDL_STATUS_H
#define MDL_STATUS_H
 
#include <QAbstractTableModel>
#include <QSqlQuery>
 
class QStatusTableModel : public QAbstractTableModel {
    Q_OBJECT
public:
    QStatusTableModel(const QSqlQuery &qry=QSqlQuery(), QObject *parent = 0)
        : QAbstractTableModel(parent), query(qry) {}
    int rowCount(const QModelIndex &parent = QModelIndex()) const;
    int columnCount(const QModelIndex &parent = QModelIndex()) const;
    QVariant data(const QModelIndex &index, int role) const;
    QVariant headerData(int section, Qt::Orientation orientation,
                        int role = Qt::DisplayRole) const;
    void setQuery(const QSqlQuery &query);
private:
    QSqlQuery query;
};
#endif

#ifndef MDL_STATUS_H
#define MDL_STATUS_H

#include <QAbstractTableModel>
#include <QSqlQuery>

class QStatusTableModel : public QAbstractTableModel {
    Q_OBJECT
public:
    QStatusTableModel(const QSqlQuery &qry=QSqlQuery(), QObject *parent = 0)
        : QAbstractTableModel(parent), query(qry) {}
    int rowCount(const QModelIndex &parent = QModelIndex()) const;
    int columnCount(const QModelIndex &parent = QModelIndex()) const;
    QVariant data(const QModelIndex &index, int role) const;
    QVariant headerData(int section, Qt::Orientation orientation,
                        int role = Qt::DisplayRole) const;
    void setQuery(const QSqlQuery &query);
private:
    QSqlQuery query;
};
#endif

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#include "mdl_status.h"
#include <QSqlRecord>
 
int QStatusTableModel::rowCount(const QModelIndex &parent) const {
    return query.size();
}
 
int QStatusTableModel::columnCount(const QModelIndex &parent) const {
    if (query.isValid() && query.size() > 0) {
        return query.record().count();
    }
    return 0;
}
 
QVariant QStatusTableModel::data(const QModelIndex &index, int role) const {
    if (!index.isValid())
        return QVariant();
    if (index.row() >= query.size())
        return QVariant();
    if (role == Qt::DisplayRole) {
        query.seek(index.row());
        return query.value(index.column());
    } else {
        return QVariant();
    }
}
 
QVariant QStatusTableModel::headerData(int section, Qt::Orientation orientation, int role) const {
    if (role != Qt::DisplayRole)
        return QVariant();
    if (orientation == Qt::Horizontal)
        return QString("Column %1").arg(section);
    else
        return QString("Row %1").arg(section);
}
 
void QStatusTableModel::setQuery(const QSqlQuery &qry) {
    query = qry;
}

#include "mdl_status.h"
#include <QSqlRecord>

int QStatusTableModel::rowCount(const QModelIndex &parent) const {
    return query.size();
}

int QStatusTableModel::columnCount(const QModelIndex &parent) const {
    if (query.isValid() && query.size() > 0) {
        return query.record().count();
    }
    return 0;
}

QVariant QStatusTableModel::data(const QModelIndex &index, int role) const {
    if (!index.isValid())
        return QVariant();
    if (index.row() >= query.size())
        return QVariant();
    if (role == Qt::DisplayRole) {
        query.seek(index.row());
        return query.value(index.column());
    } else {
        return QVariant();
    }
}

QVariant QStatusTableModel::headerData(int section, Qt::Orientation orientation, int role) const {
    if (role != Qt::DisplayRole)
        return QVariant();
    if (orientation == Qt::Horizontal)
        return QString("Column %1").arg(section);
    else
        return QString("Row %1").arg(section);
}

void QStatusTableModel::setQuery(const QSqlQuery &qry) {
    query = qry;
}

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If I try to compile this code I get the Error:
error: passing `const QSqlQuery' as `this' argument of `bool QSqlQuery::seek(int, bool)' discards qualifiers

What do I do wrong? Is there another way to display what I want?

Chris

[caduel]

nothing really.
You just try to invoke a non-const method on a const object.
Workarounds:
* get rid of the const with const_cast
*
* read the query's result into a QList<QSqlRecord> or something that you can access in the data(), rowCount() etc methods without modifiying anything