QAbstractTableModel subclass data() method implementation

[kasper360]

Hi,
I have subclassed a QAbstractTableModel to represent data from a QMap. This QMap has QLists of QSqlRecords and this map is modified by some other part of my code. I want to use this model with a QTableView to display the sql records in this map for each key. Here is my code.

#ifndef MYMODEL_H
#define MYMODEL_H
 
#include <QAbstractTableModel>
#include <QSqlRecord>
#include <QList>
 
 
class MyModel : public QAbstractTableModel
{
	Q_OBJECT
 
public:
	 MyModel(QObject *parent = 0);
	int rowCount(const QModelIndex &parent = QModelIndex()) const;
	int columnCount(const QModelIndex &parent = QModelIndex()) const;
	QVariant data(const QModelIndex &index, int role) const;
	void setRecordMap(QMap<int, QList<QSqlRecord>> *map);
	void setSelectedSerMsgIndex(QModelIndex *index);
 
private:
	QMap<int, QList<QSqlRecord>> *recordMap;
	QModelIndex *selectedSerendibMsgIndex;
};
 
#endif

#ifndef MYMODEL_H
#define MYMODEL_H

#include <QAbstractTableModel>
#include <QSqlRecord>
#include <QList>


class MyModel : public QAbstractTableModel
{
	Q_OBJECT

public:
	 MyModel(QObject *parent = 0);
	int rowCount(const QModelIndex &parent = QModelIndex()) const;
	int columnCount(const QModelIndex &parent = QModelIndex()) const;
	QVariant data(const QModelIndex &index, int role) const;
	void setRecordMap(QMap<int, QList<QSqlRecord>> *map);
	void setSelectedSerMsgIndex(QModelIndex *index);
	
private:
	QMap<int, QList<QSqlRecord>> *recordMap;
	QModelIndex *selectedSerendibMsgIndex;
};

#endif

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#include "mymodel.h"
 
 
MyModel::MyModel(QObject *parent) : QAbstractTableModel(parent)
{
 
}
 
int MyModel::rowCount(const QModelIndex &parent) const
{
	if(recordMap->isEmpty())
		return 0;
 
	int row = selectedSerendibMsgIndex->row();
	return recordMap->value(row).size();
}
 
int MyModel::columnCount(const QModelIndex &parent) const
{
	if(recordMap->isEmpty())
		return 0;
 
	int row = selectedSerendibMsgIndex->row();
	return recordMap->value(row).at(0).count();
}
 
QVariant MyModel::data(const QModelIndex &index, int role) const
{
	if(recordMap->isEmpty())
		return QVariant();
 
	if (!index.isValid())
		return QVariant();
 
	int row = selectedSerendibMsgIndex->row();
	if (index.row() >= recordMap->value(row).size())
		return QVariant();
 
	if (role == Qt::DisplayRole) 
	{
		return	recordMap->value(row).value(index.row()).value(index.column()); /* QVariant("hello");*/
	} 
	else 
	{
		return QVariant();
	}
}
 
void MyModel::setRecordMap(QMap<int, QList<QSqlRecord>> *map)
{
	recordMap = map;
}
 
void MyModel::setSelectedSerMsgIndex(QModelIndex *index)
{
	selectedSerendibMsgIndex = index;
}

#include "mymodel.h"


MyModel::MyModel(QObject *parent) : QAbstractTableModel(parent)
{

}

int MyModel::rowCount(const QModelIndex &parent) const
{
	if(recordMap->isEmpty())
		return 0;

	int row = selectedSerendibMsgIndex->row();
	return recordMap->value(row).size();
}

int MyModel::columnCount(const QModelIndex &parent) const
{
	if(recordMap->isEmpty())
		return 0;

	int row = selectedSerendibMsgIndex->row();
	return recordMap->value(row).at(0).count();
}

QVariant MyModel::data(const QModelIndex &index, int role) const
{
	if(recordMap->isEmpty())
		return QVariant();

	if (!index.isValid())
		return QVariant();

	int row = selectedSerendibMsgIndex->row();
	if (index.row() >= recordMap->value(row).size())
		return QVariant();

	if (role == Qt::DisplayRole) 
	{
		return	recordMap->value(row).value(index.row()).value(index.column()); /* QVariant("hello");*/
	} 
	else 
	{
		return QVariant();
	}
}

void MyModel::setRecordMap(QMap<int, QList<QSqlRecord>> *map)
{
	recordMap = map;
}

void MyModel::setSelectedSerMsgIndex(QModelIndex *index)
{
	selectedSerendibMsgIndex = index;
}

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But the problem is, I cannot see the data from the map. I am guessing it is because there's something wrong with my implementation of the data() method. But I can't figure out what it is. Please be kind enough to help me. Thank you.

[ChrisW67]

Have you single-stepped through data() with your debugger? Have you checked that your rowCount() implementation is correct and not returning 0 when you are no expecting it?

[kasper360]

Thanks Chris for the quick reply. I haven't used the debugger on data() method yet, and I sure will do that. But about the rowCount() implementation, I'm sure that at some point it returns something other than 0 because I am adding stuff to my QMap in another part of my code. So recordMap->isEmpty() will be false and recordMap->value(row).size() will be returned.

[kasper360]

I used the debugger on data() method, but strangely, it's never even called. Is there a particular reason for this?