Passing QVariant a pointer

[dohzer]

I'm both a Qt newbie and a C++ newbie, so bear with me.

I've created a QAbstractTableModel for use in a QTableView table.
The basic data in the model for each row of the table is a list (QList) of structures that hold three things:
1. A single letter name (type QChar)
2. An integer
3. A pointer to some data

The first two are to be displayed in the table. The third is not to be displayed in the QTableView, but is simply a pointer to data that is linked to the row.

I've implemented a "setData()" function for accessing the row data, as per an example I'm using for help, with the following parameters:

bool QAbstractItemModel::setData ( const QModelIndex & index, const QVariant & value, int role = Qt::EditRole )

bool QAbstractItemModel::setData ( const QModelIndex & index, const QVariant & value, int role = Qt::EditRole )

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When I pass the setData function the first two variable types (QChar or int) 'value', there is no problem using the data; I simply use the QVariant conversion functions to convert from QVariant to the correct types and then place the value in the appropriate table entry.
But when I want to use setData to update the pointer, I'm not sure how to do it.... Can I pass QVariant a pointer?

userTableModel.h

#ifndef USERTABLEMODEL_H
#define USERTABLEMODEL_H
 
#include <QAbstractTableModel>
#include <QList>
 
//Structure to store individual user information
struct userInfo
{
	QChar userName;
	int userNumber;
	int *userData;
};
 
class userTableModel : public QAbstractTableModel
{
	Q_OBJECT
 
public:
    userTableModel(QObject *parent=0);
    userTableModel(QList<userInfo> userInfoList, QObject *parent=0);
 
	int rowCount(const QModelIndex &parent) const;
	int columnCount(const QModelIndex &parent) const;
    	QVariant data(const QModelIndex &index, int role) const;
    	QVariant headerData(int section, Qt::Orientation orientation, int role) const;
    	Qt::ItemFlags flags(const QModelIndex &index) const;
	bool setData(const QModelIndex &index, const QVariant &value, int role=Qt::EditRole);
    	bool insertRows(int position, int rows, const QModelIndex &index=QModelIndex());
    	bool removeRows(int position, int rows, const QModelIndex &index=QModelIndex());
   	QList<userInfo> getList();
 
private:
	QString systemName;
	int systemNumber;
 
	QList<userInfo> listOfUserInfo;    //List of user info
};
 
#endif

#ifndef USERTABLEMODEL_H
#define USERTABLEMODEL_H

#include <QAbstractTableModel>
#include <QList>

//Structure to store individual user information
struct userInfo
{
	QChar userName;
	int userNumber;
	int *userData;
};

class userTableModel : public QAbstractTableModel
{
	Q_OBJECT

public:
    userTableModel(QObject *parent=0);
    userTableModel(QList<userInfo> userInfoList, QObject *parent=0);

	int rowCount(const QModelIndex &parent) const;
	int columnCount(const QModelIndex &parent) const;
    	QVariant data(const QModelIndex &index, int role) const;
    	QVariant headerData(int section, Qt::Orientation orientation, int role) const;
    	Qt::ItemFlags flags(const QModelIndex &index) const;
	bool setData(const QModelIndex &index, const QVariant &value, int role=Qt::EditRole);
    	bool insertRows(int position, int rows, const QModelIndex &index=QModelIndex());
    	bool removeRows(int position, int rows, const QModelIndex &index=QModelIndex());
   	QList<userInfo> getList();

private:
	QString systemName;
	int systemNumber;

	QList<userInfo> listOfUserInfo;    //List of user info
};

#endif

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setData() from userTableModel.cpp (note line 17)

bool userTableModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
	if (index.isValid() && role == Qt::EditRole) {
		int row = index.row();
 
		//Select the correct row
		userInfo p = listOfUserInfo.value(row);
 
		//User's Name (Initial)
		if(index.column() == 0)
                	p.userName = value.toChar();
		//User's Number
		else if(index.column() == 1)
                	p.userNumber = value.toInt();
		//Pointer to User's Data
		else if(index.column() == 2)
                	//Not Sure what to put here!!!
 
	else
		return false;
 
	listOfUserInfo.replace(row, p);
		emit(dataChanged(index, index));
 
	return true;
	}
 
	return false;
}

bool userTableModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
	if (index.isValid() && role == Qt::EditRole) {
		int row = index.row();

		//Select the correct row
		userInfo p = listOfUserInfo.value(row);

		//User's Name (Initial)
		if(index.column() == 0)
                	p.userName = value.toChar();
		//User's Number
		else if(index.column() == 1)
                	p.userNumber = value.toInt();
		//Pointer to User's Data
		else if(index.column() == 2)
                	//Not Sure what to put here!!!

	else
		return false;

	listOfUserInfo.replace(row, p);
		emit(dataChanged(index, index));

	return true;
	}

	return false;
}

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How would I use the same function (setData()) to update the "userInfo.userData" pointer?

[pervlad]

Try this
in setData():

else if(index.column() == 2)
   *(p.userData) = value.toInt();

else if(index.column() == 2)
   *(p.userData) = value.toInt();

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data() function should return *(p.userData) in case of second column

[pervlad]

I have noticed line 7 in your code userInfo p = listOfUserInfo.value(row);
QList<T>::value() function returns copy of structure that is referenced by list. More over operator=() will call default copy constructor
Try

userInfo &p = listOfUserInfo.value[row];

userInfo &p = listOfUserInfo.value[row];

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