Qt和网页中的JavaScript函数相互调用的达成

发布时间：2021-12-16 12:51:13 所属栏目：教程来源：互联网

导读：下面的说明来自Qt源代码中的qwebpluginfactory.cpp文件中的介绍说明，引用一下。 /*! class QWebPluginFactory since 4.4 brief The QWebPluginFactory class is used to embed custom data types in web pages. inmodule QtWebKit The HTML c{object}

下面的说明来自Qt源代码中的qwebpluginfactory.cpp文件中的介绍说明，引用一下。
/*!
    class QWebPluginFactory
    since 4.4
    brief The QWebPluginFactory class is used to embed custom data types in web pages.

    inmodule QtWebKit

    The HTML c{<object>} tag is used to embed arbitrary content into a web page,
    for example:

    code
    <object type="application/x-pdf" data="http://qt.nokia.com/document.pdf" width="500" height="400"></object>
    endcode

    QtWebkit will natively handle the most basic data types like c{text/html} and
    c{image/jpeg}, but for any advanced or custom data types you will need to
    provide a handler yourself.

    QWebPluginFactory is a factory for creating plugins for QWebPage, where each
    plugin provides support for one or more data types. A plugin factory can be
    installed on a QWebPage using QWebPage::setPluginFactory().

    note The plugin factory is only used if plugins are enabled through QWebSettings.

    You provide a QWebPluginFactory by implementing the plugins() and the
    create() methods. For plugins() it is necessary to describe the plugins the
    factory can create, including a description and the supported MIME types.
    The MIME types each plugin can handle should match the ones specified in
    in the HTML c{<object>} tag of your content.

    The create() method is called if the requested MIME type is supported. The
    implementation has to return a new instance of the plugin requested for the
    given MIME type and the specified URL.

    The plugins themselves are subclasses of QObject, but currently only plugins
    based on either QWidget or QGraphicsWidget are supported.
---------------------------------------------------------------------------------------------
一、按照上面给出的说明，如果要实现一个可以被网页中的JS调用的Qt方法，需要注意：
1. 需要继承QWebPluginFactory来实现自己的plugin类
2. 重载自定义plugin类的create()和plugins()方法
3. create()要实现创建特定的工JS调用的对象
4. plugins() 需要返回适当的QList<>
5. JS调用的方法的对象需要继承自QWidget或者QGraphicsWidget，而不是QObject

二、给出的实例代码如下：
     定义JS调用方法的对象：
          class IntelliPlugin : public QWebPluginFactory
     实现其对应的create()和plugins()方法：

QObject* IntelliPlugin::create(const QString &mimeType, const QUrl &, const QStringList &argumentNames, const QStringList &argumentValues) const

{
        qDebug() << " IntelliPlugin::create()"<<endl;
        foreach (MimeType mime, this->m_mimeType) {
                if (!mime.name.isEmpty() && mime.name==mimeType) {
                        if (mimeType == "application/print-plugin") {
                                qDebug() << "create shine print"<<endl;
                               ShinePrint * pShinePrint = new ShinePrint(); /*ShinePrint就是JS调用方法的类*/
                                qDebug() << "finish create shine print."<<endl;
                               return pShinePrint;
                        }
                }
        }
        return NULL;
}

QList<IntelliPlugin::Plugin> IntelliPlugin::plugins() const
{
        Plugin plugin;
        plugin.name = "application/print-plugin";
        plugin.description = "Just for PrintMessage call test";
        plugin.mimeTypes.append(m_mimeType);
        QList<IntelliPlugin::Plugin> plugList;
        plugList.append(plugin);
        return plugList;
}
在main函数中需要执行的代码：
    view = new QWebView;
    view->setWindowFlags(Qt::FramelessWindowHint);
    view->setGeometry(50, 50, 1024, 768);
    view->settings()->setAttribute(QWebSettings::PluginsEnabled, true);
    view->settings()->setAttribute(QWebSettings::JavascriptEnabled, true);
    view->page()->setPluginFactory(new IntelliPlugin);
    view->load(QUrl("test_2.html"));
    view->show();

三、下面是test_2.html中JS调用Qt方法：
    <object type="application/print-plugin" data="http://www.sohu.com" width="1" height="1" id="Callobject">
    </object>
    <script type="text/javascript">
        function print() {
            var s5 = "请耐心等待，过号请到分诊台重新分诊，谢谢合作";
            /*调用的Qt中的方法: class ShinePrint::void PrintMessag(QString msg)*/
            var printResult = document.getElementById("Callobject").PrintMessag(s5);
            if (printResult < 0)
                alert("网络出现故障，打印失败，请联系管理员");
        }

        function JavaAlert() {
                alert("这是JavaScript中的函数JavaAlert()被Qt程序调用才会出现的提示");
        }
    </script>

四、在Qt中调用JS中的函数：
       view->page()->mainFrame()->evaluateJavaScript("JavaAlert();");

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