QT: unresolved external symbol while trying to get webpage source code

Question

I started developing with Qt and I'm trying to get webpage source code. Here's what I have :

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QString>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QNetworkAccessManager>
#include <QUrl>


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

MainWindow::~MainWindow()
{
    delete ui;
}

/**/

class GetHTMLSource : public QObject
{
Q_OBJECT

public:
    GetHTMLSource();
    void GetSource();

public slots:
    void GetDone(QNetworkReply*);

private:
    QNetworkAccessManager* NetManager;
};


GetHTMLSource::GetHTMLSource()
{
    NetManager = new QNetworkAccessManager(this);

    connect(NetManager, SIGNAL(finished(QNetworkReply*)),
         this, SLOT(GetDone(QNetworkReply*)));

}

void GetHTMLSource::GetSource()
{
    NetManager->get(QNetworkRequest(QUrl("http://stackoverflow.com")));
}

void GetHTMLSource::GetDone(QNetworkReply* ReplyIn)
{

    QByteArray DataIn=ReplyIn->readAll();
    QString DataString(DataIn);

    //process str any way you like!

}

/**/

void MainWindow::on_pushButton_clicked()
{
    GetHTMLSource Test;
    Test.GetSource();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

.pro

QT       += core gui

TARGET = TestGetPageSource
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

QT += network

Errors are :

mainwindow.obj:-1: error:LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __thiscall GetHTMLSource::metaObject(void)const " (?metaObject@GetHTMLSource@@UBEPBUQMetaObject@@XZ)

mainwindow.obj:-1: error:LNK2001: unresolved external symbol "public: virtual void * __thiscall GetHTMLSource::qt_metacast(char const *)" (?qt_metacast@GetHTMLSource@@UAEPAXPBD@Z)

mainwindow.obj:-1: error:LNK2001: unresolved external symbol "public: virtual int __thiscall GetHTMLSource::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@GetHTMLSource@@UAEHW4Call@QMetaObject@@HPAPAX@Z)

Answer 1

Generally if you create classes derived from QObject you have to put them in separate header and source files.

So one .h and one .cpp file for one class.

Answer 2

Fixed it on my own. Of course it was my stupid mistake.

In class definition :

public slots:
    void GetDone(QNetworkReply*);

was not matching actual function :

void GetHTMLSource::GetDone(QNetworkReply* ReplyIn)
{ ... }

However moving it to seperated .h and .cpp files probably helped.