基本 QNetworkAccessManager 发送请求失败答案

【问题标题】：basic QNetworkAccessManager fails to send requestion基本 QNetworkAccessManager 发送请求失败
【发布时间】：2014-06-15 00:01:55
【问题描述】：

虽然没有任何请求数据包到达我的服务器，但我的代码中没有错误。我运行 tcpdump 端口 80 并且没有任何东西穿过线路，wireshark 也是这么说的。

//coreeng.h

#ifndef COREENG_H
#define COREENG_H

#include <QObject>
#include <QNetworkAccessManager>

class coreEng : public QObject
{
    Q_OBJECT
        public:



        private slots:

        public slots:
            void connect();
            void url();
            void finishedSlot(QNetworkReply* reply);


        private:
            QNetworkAccessManager* nam;

};

#endif // COREENG_H

//coreengine.cpp

#include "coreeng.h"
#include <QNetworkAccessManager>
#include <QUrl>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QImageReader>

coreEng::coreEng(QObject *parent) :
    QObject(parent)
{
}

explicit coreEng(QObject *parent = 0)
    {
        nam = new QNetworkAccessManager();
    }

void coreEng::connect(){
    QObject::connect(nam, SIGNAL(finished(QNetworkReply*)),
    this, SLOT(finishedSlot(QNetworkReply*)));
}

void coreEng::url(){
    QUrl url("http://www.myserver.com");
    QNetworkReply* reply = nam->get(QNetworkRequest(url));
}

void coreEng::finishedSlot(QNetworkReply* reply){

    QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);

    QVariant redirectionTargetUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute);

    if (reply->error() == QNetworkReply::NoError)
    {

        QImageReader imageReader(reply);
        QImage pic = imageReader.read();

        QByteArray bytes = reply->readAll();  // bytes
        QString string(bytes); // string
    }

    else
    {

    }

    delete reply();

}

//main.cpp

#include <QCoreApplication>
#include "coreeng.h"

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    coreEng mConnect;
    mConnect.connect();

    return a.exec();
}

【问题讨论】：

标签： c++ qt qnetworkaccessmanager

【解决方案1】：

你永远不会打电话给coreEng::url()，所以你永远不会提出请求。

我也不确定您的构造函数是否正确。为什么不直接放弃显式构造函数并在默认构造函数中创建 QNetworkAccessManager？

【讨论】：