Qt QNetworkAccessManager and multiple QNetworkReply

问题

I have two get QNetworkRequest.

I want to handle finished signals from different methods.

For example this is code in

  MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    GetUserData();
    connect(nam, SIGNAL(finished(QNetworkReply*)), this, SLOT(GetUserDataCompleted(QNetworkReply*)));

    GetMessages();
    connect(nam, SIGNAL(finished(QNetworkReply*)), this, SLOT(GetMessagesCompleted(QNetworkReply*)));
}

This my one method

I have tried replay->deleteLater(); but same result

Please advice me something useful

void MainWindow::GetUserDataCompleted(QNetworkReply *replay)
{
    if(replay->error() == QNetworkReply::NoError)
    {
        QString getData = replay->readAll();
        QMessageBox msg;

        if(getData == "1")
        {
            msg.setText("User Is not Exits");
        }
        else
        {
            QDomDocument doc;

            if(doc.setContent(getData))
            {
                QDomElement domElem = doc.documentElement();

                QDomNode n = domElem.firstChild();
                while(!n.isNull()) {
                    QDomElement e = n.toElement(); // try to convert the node to an element.
                    if(!e.isNull()) {
                        msg.setText(e.namedItem("Image").childNodes().at(0).nodeValue());
                        msg.exec();
                    }
                    n = n.nextSibling();
                }
            }

            replay->deleteLater();
        }
    }
}

回答1:

You can create a RequestSender class whose role is looking after requests.

Each RequestSender object will handle one unique request. While creating the QNetworkRequest that will be sent, the RequestSender will "tag" its own request with the originatingObject attribute. This attribute indicates which object sent the request. When a RequestSender object receives a reply, it will look if it is the sender of the request via the originatingObject attribute. For further informations about originatingObject, you can refer to the documentation here : http://qt-project.org/doc/qt-4.8/qnetworkrequest.html#originatingObject

Below is an example of what you can do.

requestsender.hpp :

class RequestSender {
    public:
        RequestSender();
        ~RequestSender();
        void createRequest(/* Request parameters */);

    public slots:
        void endRequest(QNetworkReply* replay);
};

requestsender.cpp :

RequestSender::RequestSender() {
    connect(nam, SIGNAL(finished(QNetworkReply*)), this, SLOT(endRequest(QNetworkReply*)));
}

RequestSender::~RequestSender() {
    disconnect(nam, SIGNAL(finished(QNetworkReply*)), this, SLOT(endRequest(QNetworkReply*)));
}

void RequestSender::createRequest(/* Request parameters */) {
    QNetworkRequest * myRequest = 0;

    // Build myRequest with the request parameters

    myRequest->setOriginatingObject(this);
    nam->get(*myRequest);

}

void RequestSender::endRequest(QNetworkReply* replay) {
    if (replay->request().originatingObject() != this) {
        // That's not the request sent by the object -> stop the method here !
        return;
    }

    // Treatments on replay
}

回答2:

Every operation you do with your QNetworkAccessManager will return a QNetworkReply. This has also has an signal finished(). Maybe you can connect this signal to your different slots.

来源：https://stackoverflow.com/questions/12077211/qt-qnetworkaccessmanager-and-multiple-qnetworkreply

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