How to write a QList into a binary file?

[Lawand]

I think outputStream should be a QDataStream instead of QDataStream* for your code to work...

Or (if it has to be a QDataStream*) you gotta find another to call operator<<() such as:

(*outputStream) << listofServers

(*outputStream) << listofServers

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[eekhoorn12]

Thanks that solved the problem but created a new one.
I now get the following error:

f:/Qt/2009.02/qt/include/QtCore/../../src/corelib/io/qdatastream.h: In function 'QDataStream& operator<<(QDataStream&, const QList<T>&) [with T = Server]':
serverlist.cpp:45: instantiated from here
f:/Qt/2009.02/qt/include/QtCore/../../src/corelib/io/qdatastream.h:252: error: no match for 'operator<<' in 's << (+l)->QList<T>::at [with T = Server](i)'

f:/Qt/2009.02/qt/include/QtCore/../../src/corelib/io/qdatastream.h: In function 'QDataStream& operator<<(QDataStream&, const QList<T>&) [with T = Server]':
serverlist.cpp:45: instantiated from here
f:/Qt/2009.02/qt/include/QtCore/../../src/corelib/io/qdatastream.h:252: error: no match for 'operator<<' in 's << (+l)->QList<T>::at [with T = Server](i)'

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[Lawand]

What are the types of server.serverAddres and server.serverUseSsl? because you might have to overload operator<<() and operator>>() on them...
As the Assistant puts it:

The QDataStream class implements the serialization of C++'s basic data types, like char, short, int, char *, etc. Serialization of more complex data is accomplished by breaking up the data into primitive units.

[eekhoorn12]

Server consits of a few QString's some bool's and qint32.

[Lawand]

Would you post the full code of the serverlist.cpp file

[eekhoorn12]

This is the serverlist.cpp:

#include <QDir>
#include <QMessageBox>
 
#include "serverlist.h"
 
QList<Server> listofServers;
 
 
serverList::serverList()
{
    settings = new Settings();
    QFile serverDataFile(settings->getappDataDir() + QDir::separator() + "servers" + QDir::separator() + "servers.dat");
    serverDataFileInfo = new QFileInfo(serverDataFile);
    QDataStream outputStream(&serverDataFile);
    QDataStream inputStream(&serverDataFile);
}
 
void serverList::saveServers()
{
    if(serverDataFileInfo->exists())
    {
        QDir newFile(serverDataFileInfo->absoluteFilePath());
        newFile.mkpath(serverDataFileInfo->absolutePath());
    }
    if(!serverDataFile.open(QIODevice::ReadWrite))
    {
        QMessageBox::critical( 0, "Post program","There was a problem reading the server settings file" );
    }
    outputStream << listofServers;
}
 
void serverList::addServer(Server newServer)
{
}

#include <QDir>
#include <QMessageBox>

#include "serverlist.h"

QList<Server> listofServers;


serverList::serverList()
{
    settings = new Settings();
    QFile serverDataFile(settings->getappDataDir() + QDir::separator() + "servers" + QDir::separator() + "servers.dat");
    serverDataFileInfo = new QFileInfo(serverDataFile);
    QDataStream outputStream(&serverDataFile);
    QDataStream inputStream(&serverDataFile);
}

void serverList::saveServers()
{
    if(serverDataFileInfo->exists())
    {
        QDir newFile(serverDataFileInfo->absoluteFilePath());
        newFile.mkpath(serverDataFileInfo->absolutePath());
    }
    if(!serverDataFile.open(QIODevice::ReadWrite))
    {
        QMessageBox::critical( 0, "Post program","There was a problem reading the server settings file" );
    }
    outputStream << listofServers;
}

void serverList::addServer(Server newServer)
{
}

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This is the serverlist.h:

#ifndef SERVERLIST_H
#define SERVERLIST_H
 
#include <QList>
#include <QFile>
#include <QFileInfo>
#include <QDataStream>
 
#include <server.h>
#include <settings.h>
 
class serverList
{
public:
    serverList();
    void saveServers();
    void addServer(Server newServer);
    void loadServers();
 
private:
    static QList<Server> listofServers;
    Settings *settings;
    QFileInfo *serverDataFileInfo;
    QFile serverDataFile;
    QDataStream outputStream;
    QDataStream inputStream;
};
 
#endif // SERVERLIST_H

#ifndef SERVERLIST_H
#define SERVERLIST_H

#include <QList>
#include <QFile>
#include <QFileInfo>
#include <QDataStream>

#include <server.h>
#include <settings.h>

class serverList
{
public:
    serverList();
    void saveServers();
    void addServer(Server newServer);
    void loadServers();

private:
    static QList<Server> listofServers;
    Settings *settings;
    QFileInfo *serverDataFileInfo;
    QFile serverDataFile;
    QDataStream outputStream;
    QDataStream inputStream;
};

#endif // SERVERLIST_H

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I will post the Server class also to get the complete picture
server.cpp:

#include "server.h"
//#include <QDataStream>
 
Server::Server()
{
}
 
void Server::setAddres(QString newAddres)
{
    serverAddres = newAddres;
}
 
void Server::setNickname(QString newNickname)
{
    serverNickname = newNickname;
}
 
void Server::setPort(qint32 newPort)
{
    serverPort = newPort;
}
 
void Server::setConnections(qint32 newConnections)
{
    serverConnections = newConnections;
}
 
void Server::setUsername(QString newUsername)
{
    serverUsername = newUsername;
}
 
void Server::setPassword(QString newPassword)
{
    serverPassword = newPassword;
}
 
void Server::setRequireLogin(bool newRequireLogin)
{
    serverRequireLogin = newRequireLogin;
}
 
void Server::setUseSsl(bool newUseSsl)
{
    serverUseSsl = newUseSsl;
}
 
QString Server::getAddres()
{
    return serverAddres;
}
 
QString Server::getNickname()
{
    return serverNickname;
}
 
qint32  Server::getPort()
{
    return serverPort;
}
 
qint32  Server::getConnections()
{
    return serverConnections;
}
 
QString Server::getUsername()
{
    return serverUsername;
}
 
QString Server::getPassword()
{
    return serverPassword;
}
 
bool    Server::getRequireLogin()
{
    return serverRequireLogin;
}
 
bool    Server::getUseSsl()
{
    return serverUseSsl;
}
 
 
 
QDataStream& operator<<(QDataStream& out, const Server& server)
{
    out << server.serverAddres;
    out << server.serverNickname;
    out << server.serverPort;
    out << server.serverConnections;
    out << server.serverUsername;
    out << server.serverPassword;
    out << server.serverRequireLogin;
    out << server.serverUseSsl;
    return out;
}
QDataStream& operator>>(QDataStream& in,Server& server)
{
    in >> server.serverAddres;
    in >> server.serverNickname;
    in >> server.serverPort;
    in >> server.serverConnections;
    in >> server.serverUsername;
    in >> server.serverPassword;
    in >> server.serverRequireLogin;
    in >> server.serverUseSsl;
    return in;
}

#include "server.h"
//#include <QDataStream>

Server::Server()
{
}

void Server::setAddres(QString newAddres)
{
    serverAddres = newAddres;
}

void Server::setNickname(QString newNickname)
{
    serverNickname = newNickname;
}

void Server::setPort(qint32 newPort)
{
    serverPort = newPort;
}

void Server::setConnections(qint32 newConnections)
{
    serverConnections = newConnections;
}

void Server::setUsername(QString newUsername)
{
    serverUsername = newUsername;
}

void Server::setPassword(QString newPassword)
{
    serverPassword = newPassword;
}

void Server::setRequireLogin(bool newRequireLogin)
{
    serverRequireLogin = newRequireLogin;
}

void Server::setUseSsl(bool newUseSsl)
{
    serverUseSsl = newUseSsl;
}

QString Server::getAddres()
{
    return serverAddres;
}

QString Server::getNickname()
{
    return serverNickname;
}

qint32  Server::getPort()
{
    return serverPort;
}

qint32  Server::getConnections()
{
    return serverConnections;
}

QString Server::getUsername()
{
    return serverUsername;
}

QString Server::getPassword()
{
    return serverPassword;
}

bool    Server::getRequireLogin()
{
    return serverRequireLogin;
}

bool    Server::getUseSsl()
{
    return serverUseSsl;
}



QDataStream& operator<<(QDataStream& out, const Server& server)
{
    out << server.serverAddres;
    out << server.serverNickname;
    out << server.serverPort;
    out << server.serverConnections;
    out << server.serverUsername;
    out << server.serverPassword;
    out << server.serverRequireLogin;
    out << server.serverUseSsl;
    return out;
}
QDataStream& operator>>(QDataStream& in,Server& server)
{
    in >> server.serverAddres;
    in >> server.serverNickname;
    in >> server.serverPort;
    in >> server.serverConnections;
    in >> server.serverUsername;
    in >> server.serverPassword;
    in >> server.serverRequireLogin;
    in >> server.serverUseSsl;
    return in;
}

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server.h

#ifndef SERVER_H
#define SERVER_H
 
#include <QString>
#include <QtGlobal>
 
 
class Server
{
public:
    Server();
 
    //Set functions
    void setAddres(QString newAddres);
    void setNickname(QString newNickname);
    void setPort(qint32 newPort);
    void setConnections(qint32 newConnections);
    void setUsername(QString newUsername);
    void setPassword(QString newPassword);
    void setRequireLogin(bool newRequireLogin);
    void setUseSsl(bool newUseSsl);
 
    //Get functions
    QString getAddres();
    QString getNickname();
    qint32  getPort();
    qint32  getConnections();
    QString getUsername();
    QString getPassword();
    bool    getRequireLogin();
    bool    getUseSsl();
 
private:
    QString serverAddres;
    QString serverNickname;
    qint32  serverPort;
    qint32  serverConnections;
    QString serverUsername;
    QString serverPassword;
    bool    serverRequireLogin;
    bool    serverUseSsl;
};
#endif // SERVER_H

#ifndef SERVER_H
#define SERVER_H

#include <QString>
#include <QtGlobal>


class Server
{
public:
    Server();

    //Set functions
    void setAddres(QString newAddres);
    void setNickname(QString newNickname);
    void setPort(qint32 newPort);
    void setConnections(qint32 newConnections);
    void setUsername(QString newUsername);
    void setPassword(QString newPassword);
    void setRequireLogin(bool newRequireLogin);
    void setUseSsl(bool newUseSsl);

    //Get functions
    QString getAddres();
    QString getNickname();
    qint32  getPort();
    qint32  getConnections();
    QString getUsername();
    QString getPassword();
    bool    getRequireLogin();
    bool    getUseSsl();

private:
    QString serverAddres;
    QString serverNickname;
    qint32  serverPort;
    qint32  serverConnections;
    QString serverUsername;
    QString serverPassword;
    bool    serverRequireLogin;
    bool    serverUseSsl;
};
#endif // SERVER_H

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[Lawand]

In my case, I declared the functions operator<<() and operator>>() in the .h file and implemented them in the .cpp file, and when I tried removing the declarations from the .h file I got the very same error you got.

So, put those 2 lines in the server.h file:

QDataStream& operator<<(QDataStream& out, const Server& server);
QDataStream& operator>>(QDataStream& in,Server& server);

QDataStream& operator<<(QDataStream& out, const Server& server);
QDataStream& operator>>(QDataStream& in,Server& server);

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[eekhoorn12]

Thanks that worked. Now i have to look at my implementation of the reading of a file because it is complaining about a missing operator at the bool's and qint32's but they should be available according to the documentation.

O:/projects/Post_Program/server.cpp:107: error: no match for 'operator>>' in 'in >> server->Server::serverPort'

O:/projects/Post_Program/server.cpp:107: error: no match for 'operator>>' in 'in >> server->Server::serverPort'

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[Lawand]

Wait a minute, aren't those members private? how are you accessing them directly?

[eekhoorn12]

To test it i made the public.

[Lawand]

That error you're getting doesn't necessarily mean what you think it means, sometimes GCC errors are ambiguous.

I copied all the code as-is into a project in my PC then added the two line I told you about (the declarations) and it turend out that you should un-hint the "#include <QDataStream>" and the error will go away...

[eekhoorn12]

I tried it and it works. Thanks everything works now.