QT源码阅读——QT与HTML交互编程

QT中通过QWebKit组件处理HTML，其中最重要的就是QWebView了~~~

通过例子formextractor我们可以窥之一二：

/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
**     of its contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include "formextractor.h"

QT_BEGIN_NAMESPACE
class QAction;
class QMenu;
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow();

private slots:
    void about();

private:
    FormExtractor *centralWidget;
    QMenu *fileMenu;
    QMenu *helpMenu;
    QAction *exitAct;
    QAction *aboutAct;
    QAction *aboutQtAct;

    void createActions();
    void createMenus();
};

#endif // MAINWINDOW_H

/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
**     of its contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include 
#include "mainwindow.h"

MainWindow::MainWindow()
{
    createActions();
    createMenus();
    centralWidget = new FormExtractor(this);
    setCentralWidget(centralWidget);
    setUnifiedTitleAndToolBarOnMac(true);
}

void MainWindow::createActions()
{
    exitAct = new QAction(tr("E&xit"), this);
    exitAct->setStatusTip(tr("Exit the application"));
    exitAct->setShortcuts(QKeySequence::Quit);
    connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

    aboutAct = new QAction(tr("&About"), this);
    aboutAct->setStatusTip(tr("Show the application's About box"));
    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

    aboutQtAct = new QAction(tr("About &Qt"), this);
    aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
}

void MainWindow::createMenus()
{
    fileMenu = menuBar()->addMenu(tr("&File"));
    fileMenu->addAction(exitAct);

    menuBar()->addSeparator();

    helpMenu = menuBar()->addMenu(tr("&Help"));
    helpMenu->addAction(aboutAct);
    helpMenu->addAction(aboutQtAct);
}

void MainWindow::about()
{
    QMessageBox::about(this, tr("About Form Extractor"),
        tr("The Form Extractor example demonstrates how to "
           "extract data from a web form using QtWebKit."));

}

核心交互类：

/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
**     of its contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef FORMEXTRACTOR_H
#define FORMEXTRACTOR_H

#include 
#include 
#include "ui_formextractor.h"

class FormExtractor : public QWidget
{
    Q_OBJECT

public:
    FormExtractor(QWidget *parent = 0, Qt::WindowFlags flags = 0);
    ~FormExtractor();

public slots:
    void submit();
    void populateJavaScriptWindowObject();

private:
    Ui::Form ui;
};

#endif // FORMEXTRACTOR_H

/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
**     of its contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "formextractor.h"

#include 

FormExtractor::FormExtractor(QWidget *parent, Qt::WindowFlags flags)
    : QWidget(parent, flags)
{
    ui.setupUi(this);
    ui.webView->setUrl(QUrl("qrc:/form.html"));
    connect(ui.webView->page()->mainFrame(), SIGNAL(javaScriptWindowObjectCleared()),
            this, SLOT(populateJavaScriptWindowObject()));
    resize(300, 300);
}

FormExtractor::~FormExtractor()
{
}

void FormExtractor::submit()
{
    QWebFrame *frame = ui.webView->page()->mainFrame();

    QWebElement firstName = frame->findFirstElement("#firstname");
    QWebElement lastName = frame->findFirstElement("#lastname");
    QWebElement maleGender = frame->findFirstElement("#genderMale");
    QWebElement femaleGender = frame->findFirstElement("#genderFemale");
    QWebElement updates = frame->findFirstElement("#updates");

    ui.firstNameEdit->setText(firstName.evaluateJavaScript("this.value").toString());
    ui.lastNameEdit->setText(lastName.evaluateJavaScript("this.value").toString());

    if (maleGender.evaluateJavaScript("this.checked").toBool())
        ui.genderEdit->setText(maleGender.evaluateJavaScript("this.value").toString());
    else if (femaleGender.evaluateJavaScript("this.checked").toBool())
        ui.genderEdit->setText(femaleGender.evaluateJavaScript("this.value").toString());

    if (updates.evaluateJavaScript("this.checked").toBool())
        ui.updatesEdit->setText("Yes");
    else
        ui.updatesEdit->setText("No");
}

void FormExtractor::populateJavaScriptWindowObject()
{
    ui.webView->page()->mainFrame()->addToJavaScriptWindowObject("formExtractor", this);
}

HTML页面：

The Green People Book Club



Welcome to The Green People Book Club. Please register to obtain a membership with us.

    

    

    

        

        First name:
        
        

            
        
    
    

        

        Last name:
        
        

            
        
    
    

        

        Gender:
        
        

         Male
         Female
        
    
    

        

        
        Check here if you would like to receive regular updates from us:
        
    
    
    
    

其中关键就是：

ui.webView->page()->mainFrame()->addToJavaScriptWindowObject("formExtractor", this);

void QWebFrame::addToJavaScriptWindowObject(const QString & name, QObject * object, ValueOwnership own = QtOwnership);

作用就是讲处理对象object作为html的window对象的javascript子对象，这样就相当于在html页面中添加了相应的javascript处理函数，实现了交互功能！