QWebEngine_C++_交互

参考网址：http://blog.csdn.net/liuyez123/article/details/50509788
　　ZC: 该文章里面的：
　　“
　　　　<ahref="javascript:document.getElementByIdx_x("myLabel").setText("通过JavaScript访问Qt对象");"mce_href="javascript:document.getElementByIdx_x("myLabel").setText("通过JavaScript访问Qt对象");">点击访问Qt对象</a>
　　”
　　　　貌似使用的机制是 "WebKik & QWebPluginFactory"，貌似在WebEngine中暂时(至20160926为止)还没有...

https://www.google.com.hk 搜索 “getElementByIdx_x("myLabel").setText QT”得到 仅有的4个结果：
　　http://www.programgo.com/article/54841979099/
　　http://blog.hehehehehe.cn/a/10652.htm
　　http://www.360doc.com/content/16/0405/18/13792507_548095953.shtml
　　http://blog.inet198.cn/?liuyez123/article/details/50509788

1、我的代码：

　　1.1、pro

QT       += core gui    
            webenginewidgets webchannel
CONFIG += c++11

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = QWebEngine_JiaoHu
TEMPLATE = app


SOURCES += main.cpp
        mainwindow.cpp 
    document.cpp 
    previewpage.cpp

HEADERS  += mainwindow.h 
    document.h 
    previewpage.h

FORMS    += mainwindow.ui

　　1.2、main.cpp ==> 默认

　　1.3、mainwindow.h 和 mainwindow.cpp

　　　　1.3.1、mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "document.h"

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;

private:
    bool isModified() const;
    Document m_content;
};

#endif // MAINWINDOW_H

　　　　1.3.2、mainwindow.cpp

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

#include "previewpage.h"
#include <QWebChannel>

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

// ***

    PreviewPage *page = new PreviewPage(this);
    ui->preview->setPage(page);
    m_content.setUi(ui);

    QWebChannel *channel = new QWebChannel(this);
    channel->registerObject(QStringLiteral("content"), &m_content);
    page->setWebChannel(channel);

    //ui->preview->setUrl(QUrl("qrc:/index.html"));
    ui->preview->setUrl(QUrl::fromUserInput("F:/ZZ_Qt5/QWebEngine_JiaoHu/html/index.html"));

    ui->editor->setPlainText("hello...
");
}

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

bool MainWindow::isModified() const
{
    return ui->editor->document()->isModified();
}

void MainWindow::on_pushButton_clicked()
{
    m_content.setSendTextText(ui->lineEdit->text());
}

　　1.4、previewpage.h 和 previewpage.cpp ==> 用于在 打开网页的时候，做一下处理(相当于过滤层) ：如果网址 如何要求就通过(打开网页)，如果 网址不符合要求 就拒绝(不打开网页)

　　　　1.4.1、previewpage.h

#ifndef PREVIEWPAGE_H
#define PREVIEWPAGE_H

#include <QWebEnginePage>

class PreviewPage : public QWebEnginePage
{
    Q_OBJECT
public:
    explicit PreviewPage(QObject *parent = nullptr) : QWebEnginePage(parent) {}

protected:
    bool acceptNavigationRequest(const QUrl &url, NavigationType type, bool isMainFrame);
};

#endif // PREVIEWPAGE_H

　　　　1.4.2、previewpage.cpp

#include "previewpage.h"

#include <QDesktopServices>

bool PreviewPage::acceptNavigationRequest(const QUrl &url,
                                          QWebEnginePage::NavigationType /*type*/,
                                          bool /*isMainFrame*/)
{
    // Only allow qrc:/index.html.
    if (url.scheme() == QString("qrc"))
        return true;
    //QDesktopServices::openUrl(url); // ZC: 这一句代码，会打开 本地的默认浏览器，显示相关的网页
    //return false; // ZC: 返回 false的话，就不打开 相应的网页
    return true;    // ZC: 返回 false的话，就打开 相应的网页
}

　　1.5、document.h 和 document.cpp ==> 这个是 JS和C++交互的类

　　　　1.5.1、document.h

#ifndef DOCUMENT_H
#define DOCUMENT_H

#include <QObject>
#include <QString>
#include "ui_mainwindow.h"

namespace Ui {
class MainWidget;
}

class Document : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString text MEMBER s_text NOTIFY sendText)

public:
    explicit Document(QObject *parent = nullptr) : QObject(parent) {}

    void setSendTextText(const QString &text);
    void setUi(Ui::MainWindow *ui);

public slots:
    void receiveText(const QString &r_text);

signals:
    void sendText(const QString &text);

private:
    void displayMessage(const QString &message);
    QString s_text;
    QString recieve_text;
    Ui::MainWindow *mainUi;
};

#endif // DOCUMENT_H

　　　　1.5.2、document.cpp

#include "document.h"
#include <QDebug>


void Document::setSendTextText(const QString &text)
{
    s_text = text;
    qDebug() << "Document::setSendTextText" << s_text;
    emit sendText(s_text);
}

void Document::displayMessage(const QString &message)
{
      mainUi->editor->appendPlainText(message);
}

/*!
    This slot is invoked from the HTML client side and the text displayed on the server side.
*/
void Document::receiveText(const QString &r_text)
{
    displayMessage(QObject::tr("Received message: %1").arg(r_text));
}

void Document::setUi(Ui::MainWindow *ui)
{
    mainUi = ui;
}

　　1.6、网页 源码

　　　　1.6.1、index.html

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <script type="text/javascript" src="./qwebchannel.js"></script>
        <script type="text/javascript">
            //BEGIN SETUP
            function output(message)
            {
                var output = document.getElementById("output");
                output.innerHTML = output.innerHTML + message + "
";
            }
            window.onload = function() {

            output("setting up QWebChannel.");
            new QWebChannel(qt.webChannelTransport, function(channel) {
                // make dialog object accessible globally
                var content = channel.objects.content;

                document.getElementById("send").onclick = function() {
                    var input = document.getElementById("input");
                    var text = input.value;
                    if (!text) {
                        return;
                    }

                    output("Sent message: " + text);
                    input.value = "";
                    content.receiveText(text);
                }

                content.sendText.connect(function(message) {
                    output("Received message: " + message);
                });

                content.receiveText("Client connected, ready to send/receive messages!");
                output("Connected to WebChannel, ready to send/receive messages!");
            });
            }

            //END SETUP
        </script>
        <style type="text/css">
            html {
                height: 100%;
                 100%;
            }
            #input {
                 400px;
                margin: 0 10px 0 0;
            }
            #send {
                 90px;
                margin: 0;
            }
            #output {
                 500px;
                height: 300px;
            }
        </style>
    </head>
    <body>
        <textarea id="output"></textarea><br />
        <input id="input" /><input type="submit" id="send" value="Send" onclick="javascript:click();" />
    </body>
</html>

　　　　1.6.2、qwebchannel.js

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Copyright (C) 2014 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtWebChannel module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

"use strict";

var QWebChannelMessageTypes = {
    signal: 1,
    propertyUpdate: 2,
    init: 3,
    idle: 4,
    debug: 5,
    invokeMethod: 6,
    connectToSignal: 7,
    disconnectFromSignal: 8,
    setProperty: 9,
    response: 10,
};

var QWebChannel = function(transport, initCallback)
{
    if (typeof transport !== "object" || typeof transport.send !== "function") {
        console.error("The QWebChannel expects a transport object with a send function and onmessage callback property." +
                      " Given is: transport: " + typeof(transport) + ", transport.send: " + typeof(transport.send));
        return;
    }

    var channel = this;
    this.transport = transport;

    this.send = function(data)
    {
        if (typeof(data) !== "string") {
            data = JSON.stringify(data);
        }
        channel.transport.send(data);
    }

    this.transport.onmessage = function(message)
    {
        var data = message.data;
        if (typeof data === "string") {
            data = JSON.parse(data);
        }
        switch (data.type) {
            case QWebChannelMessageTypes.signal:
                channel.handleSignal(data);
                break;
            case QWebChannelMessageTypes.response:
                channel.handleResponse(data);
                break;
            case QWebChannelMessageTypes.propertyUpdate:
                channel.handlePropertyUpdate(data);
                break;
            default:
                console.error("invalid message received:", message.data);
                break;
        }
    }

    this.execCallbacks = {};
    this.execId = 0;
    this.exec = function(data, callback)
    {
        if (!callback) {
            // if no callback is given, send directly
            channel.send(data);
            return;
        }
        if (channel.execId === Number.MAX_VALUE) {
            // wrap
            channel.execId = Number.MIN_VALUE;
        }
        if (data.hasOwnProperty("id")) {
            console.error("Cannot exec message with property id: " + JSON.stringify(data));
            return;
        }
        data.id = channel.execId++;
        channel.execCallbacks[data.id] = callback;
        channel.send(data);
    };

    this.objects = {};

    this.handleSignal = function(message)
    {
        var object = channel.objects[message.object];
        if (object) {
            object.signalEmitted(message.signal, message.args);
        } else {
            console.warn("Unhandled signal: " + message.object + "::" + message.signal);
        }
    }

    this.handleResponse = function(message)
    {
        if (!message.hasOwnProperty("id")) {
            console.error("Invalid response message received: ", JSON.stringify(message));
            return;
        }
        channel.execCallbacks[message.id](message.data);
        delete channel.execCallbacks[message.id];
    }

    this.handlePropertyUpdate = function(message)
    {
        for (var i in message.data) {
            var data = message.data[i];
            var object = channel.objects[data.object];
            if (object) {
                object.propertyUpdate(data.signals, data.properties);
            } else {
                console.warn("Unhandled property update: " + data.object + "::" + data.signal);
            }
        }
        channel.exec({type: QWebChannelMessageTypes.idle});
    }

    this.debug = function(message)
    {
        channel.send({type: QWebChannelMessageTypes.debug, data: message});
    };

    channel.exec({type: QWebChannelMessageTypes.init}, function(data) {
        for (var objectName in data) {
            var object = new QObject(objectName, data[objectName], channel);
        }
        // now unwrap properties, which might reference other registered objects
        for (var objectName in channel.objects) {
            channel.objects[objectName].unwrapProperties();
        }
        if (initCallback) {
            initCallback(channel);
        }
        channel.exec({type: QWebChannelMessageTypes.idle});
    });
};

function QObject(name, data, webChannel)
{
    this.__id__ = name;
    webChannel.objects[name] = this;

    // List of callbacks that get invoked upon signal emission
    this.__objectSignals__ = {};

    // Cache of all properties, updated when a notify signal is emitted
    this.__propertyCache__ = {};

    var object = this;

    // ----------------------------------------------------------------------

    this.unwrapQObject = function(response)
    {
        if (response instanceof Array) {
            // support list of objects
            var ret = new Array(response.length);
            for (var i = 0; i < response.length; ++i) {
                ret[i] = object.unwrapQObject(response[i]);
            }
            return ret;
        }
        if (!response
            || !response["__QObject*__"]
            || response.id === undefined) {
            return response;
        }

        var objectId = response.id;
        if (webChannel.objects[objectId])
            return webChannel.objects[objectId];

        if (!response.data) {
            console.error("Cannot unwrap unknown QObject " + objectId + " without data.");
            return;
        }

        var qObject = new QObject( objectId, response.data, webChannel );
        qObject.destroyed.connect(function() {
            if (webChannel.objects[objectId] === qObject) {
                delete webChannel.objects[objectId];
                // reset the now deleted QObject to an empty {} object
                // just assigning {} though would not have the desired effect, but the
                // below also ensures all external references will see the empty map
                // NOTE: this detour is necessary to workaround QTBUG-40021
                var propertyNames = [];
                for (var propertyName in qObject) {
                    propertyNames.push(propertyName);
                }
                for (var idx in propertyNames) {
                    delete qObject[propertyNames[idx]];
                }
            }
        });
        // here we are already initialized, and thus must directly unwrap the properties
        qObject.unwrapProperties();
        return qObject;
    }

    this.unwrapProperties = function()
    {
        for (var propertyIdx in object.__propertyCache__) {
            object.__propertyCache__[propertyIdx] = object.unwrapQObject(object.__propertyCache__[propertyIdx]);
        }
    }

    function addSignal(signalData, isPropertyNotifySignal)
    {
        var signalName = signalData[0];
        var signalIndex = signalData[1];
        object[signalName] = {
            connect: function(callback) {
                if (typeof(callback) !== "function") {
                    console.error("Bad callback given to connect to signal " + signalName);
                    return;
                }

                object.__objectSignals__[signalIndex] = object.__objectSignals__[signalIndex] || [];
                object.__objectSignals__[signalIndex].push(callback);

                if (!isPropertyNotifySignal && signalName !== "destroyed") {
                    // only required for "pure" signals, handled separately for properties in propertyUpdate
                    // also note that we always get notified about the destroyed signal
                    webChannel.exec({
                        type: QWebChannelMessageTypes.connectToSignal,
                        object: object.__id__,
                        signal: signalIndex
                    });
                }
            },
            disconnect: function(callback) {
                if (typeof(callback) !== "function") {
                    console.error("Bad callback given to disconnect from signal " + signalName);
                    return;
                }
                object.__objectSignals__[signalIndex] = object.__objectSignals__[signalIndex] || [];
                var idx = object.__objectSignals__[signalIndex].indexOf(callback);
                if (idx === -1) {
                    console.error("Cannot find connection of signal " + signalName + " to " + callback.name);
                    return;
                }
                object.__objectSignals__[signalIndex].splice(idx, 1);
                if (!isPropertyNotifySignal && object.__objectSignals__[signalIndex].length === 0) {
                    // only required for "pure" signals, handled separately for properties in propertyUpdate
                    webChannel.exec({
                        type: QWebChannelMessageTypes.disconnectFromSignal,
                        object: object.__id__,
                        signal: signalIndex
                    });
                }
            }
        };
    }

    /**
     * Invokes all callbacks for the given signalname. Also works for property notify callbacks.
     */
    function invokeSignalCallbacks(signalName, signalArgs)
    {
        var connections = object.__objectSignals__[signalName];
        if (connections) {
            connections.forEach(function(callback) {
                callback.apply(callback, signalArgs);
            });
        }
    }

    this.propertyUpdate = function(signals, propertyMap)
    {
        // update property cache
        for (var propertyIndex in propertyMap) {
            var propertyValue = propertyMap[propertyIndex];
            object.__propertyCache__[propertyIndex] = propertyValue;
        }

        for (var signalName in signals) {
            // Invoke all callbacks, as signalEmitted() does not. This ensures the
            // property cache is updated before the callbacks are invoked.
            invokeSignalCallbacks(signalName, signals[signalName]);
        }
    }

    this.signalEmitted = function(signalName, signalArgs)
    {
        invokeSignalCallbacks(signalName, signalArgs);
    }

    function addMethod(methodData)
    {
        var methodName = methodData[0];
        var methodIdx = methodData[1];
        object[methodName] = function() {
            var args = [];
            var callback;
            for (var i = 0; i < arguments.length; ++i) {
                if (typeof arguments[i] === "function")
                    callback = arguments[i];
                else
                    args.push(arguments[i]);
            }

            webChannel.exec({
                "type": QWebChannelMessageTypes.invokeMethod,
                "object": object.__id__,
                "method": methodIdx,
                "args": args
            }, function(response) {
                if (response !== undefined) {
                    var result = object.unwrapQObject(response);
                    if (callback) {
                        (callback)(result);
                    }
                }
            });
        };
    }

    function bindGetterSetter(propertyInfo)
    {
        var propertyIndex = propertyInfo[0];
        var propertyName = propertyInfo[1];
        var notifySignalData = propertyInfo[2];
        // initialize property cache with current value
        // NOTE: if this is an object, it is not directly unwrapped as it might
        // reference other QObject that we do not know yet
        object.__propertyCache__[propertyIndex] = propertyInfo[3];

        if (notifySignalData) {
            if (notifySignalData[0] === 1) {
                // signal name is optimized away, reconstruct the actual name
                notifySignalData[0] = propertyName + "Changed";
            }
            addSignal(notifySignalData, true);
        }

        Object.defineProperty(object, propertyName, {
            configurable: true,
            get: function () {
                var propertyValue = object.__propertyCache__[propertyIndex];
                if (propertyValue === undefined) {
                    // This shouldn't happen
                    console.warn("Undefined value in property cache for property "" + propertyName + "" in object " + object.__id__);
                }

                return propertyValue;
            },
            set: function(value) {
                if (value === undefined) {
                    console.warn("Property setter for " + propertyName + " called with undefined value!");
                    return;
                }
                object.__propertyCache__[propertyIndex] = value;
                webChannel.exec({
                    "type": QWebChannelMessageTypes.setProperty,
                    "object": object.__id__,
                    "property": propertyIndex,
                    "value": value
                });
            }
        });

    }

    // ----------------------------------------------------------------------

    data.methods.forEach(addMethod);

    data.properties.forEach(bindGetterSetter);

    data.signals.forEach(function(signal) { addSignal(signal, false); });

    for (var name in data.enums) {
        object[name] = data.enums[name];
    }
}

//required for use with nodejs
if (typeof module === 'object') {
    module.exports = {
        QWebChannel: QWebChannel
    };
}

2、Z01.html

<!DOCTYPE html>

<html>
<head>
    <meta charset="UTF-8">

    <script type="text/javascript" >
    <!--

        window.onload = function()
        {
        };

    -->
    </script>

</head>

<body>

<ahref="javascript:document.getElementByIdx_x("myLabel").setText("通过JavaScript访问Qt对象");"mce_href="javascript:document.getElementByIdx_x("myLabel").setText("通过JavaScript访问Qt对象");">点击访问Qt对象</a>

</body>
</html>

3、