Link error with Qt5 webkit - qt-creator

Question

I want to make a browser in qt5 using qtwebkit but I found some error when I get download my site. I don't know the reason. I added the webkit library, and call it in mainwindow.h:
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QtWebKit/QtWebKit>
namespace Ui { class MainWindow; }
class MainWindow : public QMainWindow {
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_pushButton_clicked();
void on_pushButton_2_clicked();
void on_pushButton_3_clicked();
void on_pushButton_4_clicked();
private:
Ui::MainWindow *ui; };
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_pushButton_clicked()
{
ui->webView->back();
}
void MainWindow::on_pushButton_2_clicked()
{
ui->webView->forward();
}
void MainWindow::on_pushButton_3_clicked()
{
ui->webView->reload();
}
void MainWindow::on_pushButton_4_clicked()
{
ui->webView->load("http://" + ui->lineEdit->text());
}
and this when i called library
#-------------------------------------------------
#
# Project created by QtCreator 2013-10-31T07:39:06
#
#-------------------------------------------------
QT += core gui QT += webkit
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = mozilabrwser TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
I tried to change the name of webkit but I still get this error:
D:\ubunto\QT5\Tools\QtCreator\bin\mozilabrwser\mainwindow.cpp:19: error:
undefined reference to `_imp___ZN8QWebView4backEv'

Answer 1

QT += core gui QT += webkit
is wrong. You seem to be using Qt 5, and in Qt 5 the correct module is webkitwidgets. 2nd issue is format, you seem to have two lines concatenated. So this should work:
QT += core gui
QT += webkitwidgets
Note: If you need to have the program compile with both Qt4 and Qt5, then you need to use conditional, adding webkit for Qt4, webkitwidgets for Qt5. But this is probably not a concern for a hobby project, no point clutteirng the .pro file with that stuff until you actually need it (you will also need some source changes and #ifdef stuff in code if you want to support both, so don't go there unless it is an important requirement).
Same two lines concatenated issue seems to be also in line TARGET = mozilabrwser TEMPLATE = app.