While developing our Blackberry 10 app, we had reached a point in the project where we now needed to make web service calls.  As other components of the app will need this service, it made sense just to create a network manager class. Initially I was unsure how this would work with signals and slots, but was pleasantly surprised at how straight forward this was.  RIM had already posted a great Tutorial and some documentation regarding QNetworkAccessManager so I was already in good shape. Although the tutorial is very good, I thought it would be beneficial to strip out the other stuff and just show the bare bones of making a web service call and listening for a response was done.

In my NetworkManager.hpp:

#include <QObject>
class NetworkManager : public QObject
{
                Q_OBJECT
public:
                NetworkManager();
                virtual ~NetworkManager();
                void makeRequest(QString URL);

private slots:
    //Handles the network reply.
    void requestFinished(QNetworkReply* reply);
private:
                QNetworkAccessManager *mNetworkAccessManager;
                QFile *mFile;
}
In my NetworkManager.cpp file 
 NetworkManager::NetworkManager()
 {
                //Instantiate my mNetworkAccessManager
                mNetworkAccessManager = new QNetworkAccessManager(this);

                //Setup up my signal and slots.
                //Notice I did not declare a signal for “finished” in my header file. This is because
                // QNetworkAccessManager will fire off this signal.

                bool result = connect(mNetworkAccessManager,
                                                SIGNAL(finished(QNetworkReply*)), this,
                                                SLOT(requestFinished(QNetworkReply*)));
                // Displays a warning message if there's an issue connecting the signal
                // and slot. This is a good practice with signals and slots as it can
                // be easier to mistype a slot or signal definition
                Q_ASSERT(result);
                Q_UNUSED(result);
}

//Call this public function with a URL to make a request.
void NetworkManager::makeRequest(QString URL)
{
                QNetworkRequest request = QNetworkRequest();
                request.setUrl(QUrl(URL));
                mNetworkAccessManager->get(request);
}

//And finally the response from the server. The important item to mention here is that you 
//have set up the slot requestFinished(…) in your header file.
 void NetworkManager::requestFinished(QNetworkReply* reply)
{
    // Check the network reply for errors
    if (reply->error() == QNetworkReply::NoError)
    {
                QString fileName = QString("%1%2").arg( appPath, "output.json");
                // Create a file in the application's data directory
                mFile = new QFile(fileName);

                                // Open the file and print an error if the file cannot be opened
                                if (!mFile->open(QIODevice::ReadWrite))
                                {
                                                qDebug() << "\n Failed to open file";
                                                return;
                                }

                                // Write to the file using the reply data and close the file
                                mFile->write(reply->readAll());
                                mFile->flush();
                                mFile->close();
                }
                else
                {
                                qDebug() << "\n Problem with the network";
                                qDebug() << "\n" << reply->errorString();
                }
}