Qt/C++ - Lesson 036. QWebView – How to make simple browser on the Qt

браузер, QWebView, webkit, Qt, ssl

Note: The lesson is deprecated. With version Qt5.6 must use WebEngine

Well, who among us does not want to write your browser? Come on, do not deny it thought about the browser exactly were. So, the Qt has QWebView class that allows you to work with webkit browser engine, which is written chromium, and, accordingly, chrome and many other browsers. Therefore, practical use of a dozen lines of code, you can make an application that can display a page of the website.

Thus, the application will be as follows. There is an address bar QLineEdit and a widget QWebView . When you enter a website address in the address bar and pressing Enter key will start getting the site and display it in QWebView . When you click on the link in the link address will be displayed in the address bar and a new page will be loaded in the widget.

Project structure for work with QWebView

• QWebViewExample.pro - the profile of the project;
• main.cpp - the main project source code file;
• mainwindow.h - header file of the main application window;
• mainwindow.cpp - file source code of the main application window;
• mainwindow.ui - form the main application window.

QWebViewExample.pro

To work with QWebView need to connect two modules: webkit and webkitwidgets .

#-------------------------------------------------
#
# Project created by QtCreator 2015-12-18T20:10:57
#
#-------------------------------------------------
 
QT       += core gui webkit webkitwidgets
 
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
TARGET = QWebViewExample
TEMPLATE = app
 
 
SOURCES += main.cpp\
        mainwindow.cpp
 
HEADERS  += mainwindow.h
 
FORMS    += mainwindow.ui

mainwindow.h

The header must declare two slots:

slotEnter() - for the handling of pressing the Enter key in the browser address bar;
slotLinkClicked(QUrl url) - to handle a click on a link on the browser page.

Также необходимо подключить библиотеки QWebView и QUrl.

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QtWebKitWidgets/QWebView>
#include <QUrl>
#include <QDebug>
 
namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    Ui::MainWindow *ui;
 
private slots:
    void slotEnter();       
    void slotLinkClicked(QUrl url); 
};
 
#endif // MAINWINDOW_H

mainwindow.cpp

For handling correctlry of a click on the link you need to install the manual processing of the event by setLinkDelegationPolicy and connect the appropriate slot to the signal linkClickek().

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    // Set the manual handling of click on link
    ui->webView->page()->setLinkDelegationPolicy(QWebPage::DelegateAllLinks);
 
    // Connect the signal pressing "Enter" in the field qlineEdit
    connect(ui->lineEdit, &QLineEdit::returnPressed, this, &MainWindow::slotEnter);
    // Connect the signal click on the link to the handler
    connect(ui->webView, &QWebView::linkClicked, this, &MainWindow::slotLinkClicked);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::slotEnter()
{
    // Load the page specified in the URL field lineEdit
    ui->webView->load(QUrl(ui->lineEdit->text()));
}
 
void MainWindow::slotLinkClicked(QUrl url)
{
    // Clicking on the link put the address in the field qlineEdit
    ui->lineEdit->setText(url.toString());
    ui->webView->load(url);     // Загружаем страницу по этой ссылке
}

Correction of errors with SSL

Chances are you have an error that resembles the following when you build the project:

qt.network.ssl: QSslSocket: cannot call unresolved function SSLv23_client_method
qt.network.ssl: QSslSocket: cannot call unresolved function SSL_CTX_new
qt.network.ssl: QSslSocket: cannot call unresolved function SSL_library_init
qt.network.ssl: QSslSocket: cannot call unresolved function ERR_get_error

The solution to this problem lies in the fact, to throw the necessary libraries to the folder where are Qt5Network.dll and Qt5Networkd.dll library. These libraries are libeay32.dll and ssleay32.dll .

For this:

1. Go to the following site
2. We are looking for light build of OpenSSL
3. And shakes the required version of 32 or 64 bits (in the case of mingw swing 32-bit assembly).
4. Next install OpenSSL in derivative folder item noting "The OpenSSL binaries (\ bin) directory"
5. Then we look for the libraries libeay32.dll and ssleay32.dll and we move them to a folder with the Qt libraries Qt5Network.dll and Qt5Networkd.dll.

Result

As a result of the work done, you can open a page of the site in its own application, as shown in the following figure.

Link to the project download in zip-archive: qwebviewexample.zip

Video