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02-QWebEngineView的使用

Qt WebEngine_hitzsf的博客-CSDN博客

一、QWebEngineView

QWebEngineView 类是一个实现Web浏览器的便捷类,提供了back() 、forward()、reload()、stop() 等方法,可轻松实现页面的前进、后退、重载等导航功能,要实现一个简单的只有网页加载网页预览、没有导航功能的web浏览器,只需要定义一个 QWebEngineView 类对象,使用load方法加载即可。下面是一个简单浏览器的实现

1、Widget类定义(widget.h)

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QUrl>
class Widget : public QWidget
{
Q_OBJECT
public:
explicit Widget(QWidget *parent = nullptr, QUrl url = QUrl("http://www.baidu.com"));
signals:
};
#endif // WIDGET_H

2、Widget类实现(widget.cpp)

#include "widget.h"
#include <QtWebEngineWidgets>
#include "mywebengineview.h"

Widget::Widget(QWidget *parent, QUrl url)
    : QWidget(parent)
{
    MyWebEngineView *view = new MyWebEngineView;
    QVBoxLayout *mainLayout = new QVBoxLayout(this);

    mainLayout->addWidget(view);
    mainLayout->setContentsMargins(0,0,0,0);
    mainLayout->setMargin(0);

    this->setContentsMargins(0,0,0,0);
    this->setWindowFlags(Qt::FramelessWindowHint); // 去掉标题栏

    view->load(url);
}

3、MyWebEngineView类定义(mywebengineview.h)

#ifndef MYWEBENGINEVIEW_H
#define MYWEBENGINEVIEW_H
#include <QtWebEngineWidgets>

class MyWebEngineView : public QWebEngineView
{
    Q_OBJECT
public:
    explicit MyWebEngineView(QWidget *parent = nullptr);

    QWebEngineView * createWindow(QWebEnginePage::WebWindowType type) override;
    void linkHovered(QString url);
    void lessheadPagePrintfToPdf(bool ok);

private:
    QUrl newUrl;
    QWebEnginePage lessHeadPage;
};

#endif // MYWEBENGINEVIEW_H

4、MyWebEngineView类实现(mywebengineview.cpp)

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

MyWebEngineView::MyWebEngineView(QWidget *parent) : QWebEngineView(parent)
{
    connect(this->page(),&QWebEnginePage::linkHovered,this,&MyWebEngineView::linkHovered);
    connect(&lessHeadPage,&QWebEnginePage::loadFinished,this,&MyWebEngineView::lessheadPagePrintfToPdf);
}

//这个函数应该是由底层的QWebEnginePage发起调用的,如果不想新建QWebEngineView,在这儿覆写。
QWebEngineView *MyWebEngineView::createWindow(QWebEnginePage::WebWindowType type)
{
    Q_UNUSED(type)

    //识别要无头浏览输出pdf
    if (newUrl.toString() == "https://www.baidu.com/s?wd=小米汽车&sa=fyb_n_homepage&rsv_dl=fyb_n_homepage&from=super&cl=3&tn=baidutop10&fr=top1000&rsv_idx=2&hisfilter=1" ||
        newUrl.toString() == "https://www.baidu.com/s?wd=国风浩荡+文脉赓续&sa=fyb_n_homepage&rsv_dl=fyb_n_homepage&from=super&cl=3&tn=baidutop10&fr=top1000&rsv_idx=2&hisfilter=1")
    {
        lessHeadPage.load(newUrl);
    }
    else
    {
        this->load(newUrl);
    }

    qDebug() << "createWindow url is :" <<this->url();

    return 0;
}

void MyWebEngineView::linkHovered(QString url)
{
    qDebug() << "linkHovered url is :" <<url;

    newUrl = QUrl(url);
}

//实现无头浏览输出pdf
void MyWebEngineView::lessheadPagePrintfToPdf(bool ok)
{
    Q_UNUSED(ok)
    lessHeadPage.printToPdf(QString("test.pdf"));
}

5、主函数(main.cpp)

#include <QApplication>
#include <QWebEngineProfile>
#include <QWebEngineSettings>
#include <QWebEnginePage>
#include <QWebEngineView>
#include <QtWebEngineWidgets>
#include "mywebengineview.h"
#include "widget.h"

QUrl commandLineUrlArgument()
{
    const QStringList args = QCoreApplication::arguments();
    for (const QString &arg : args.mid(1)) {
        if (!arg.startsWith(QLatin1Char('-')))
            return QUrl::fromUserInput(arg);
    }
    //return QUrl(QStringLiteral("http://www.wanweitech.cn"));
    return QUrl(QStringLiteral("http://192.168.9.26:3006/#/Alautomdix"));
    //return QUrl(QStringLiteral("http://www.baidu.com"));
}

int main(int argc, char *argv[])
{
    QCoreApplication::setOrganizationName("qtweb_widget");
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);

    QApplication app(argc, argv);

    QWebEngineSettings::defaultSettings()->setAttribute(QWebEngineSettings::PluginsEnabled, true); //启用加载插件
    QWebEngineSettings::defaultSettings()->setAttribute(QWebEngineSettings::PdfViewerEnabled, true); //启用PDF查看
#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
    QWebEngineSettings::defaultSettings()->setAttribute(QWebEngineSettings::DnsPrefetchEnabled, true);
    QWebEngineProfile::defaultProfile()->setUseForGlobalCertificateVerification();
#endif

    QUrl url = commandLineUrlArgument();
    Widget view(nullptr, url);
    view.showFullScreen(); //全屏显示

    return app.exec();
}

二、无头浏览器

无头浏览器(Headless Browser)是一种没有图形用户界面(GUI)的浏览器。它通过在内存中渲染页面,然后将结果发送回请求它的用户或程序来实现对网页的访问,而不会在屏幕上显示网页。这种方式使得无头浏览器不仅适用于网络爬虫和测试等自动化任务,而且还能够更安全地进行网页浏览,因为它不会在屏幕上显示您的活动。

常见的无头浏览器包括Chrome Headless、PhantomJS、Puppeteer等,常见的这些无头浏览器都属于互联网前后端开发相关的东西,与Qt技术栈相关的比较少

1、基于QWebEnginePage实现无头浏览器

QWebEngine有两种实现方式,一个QWidget框架下的QWebEngineView,另一种是QML框架下的WebEngineView,其中QWebEngineView包含QWebEnginePage的功能,QWebEnginePage提供页面加载相关的功能,QWebEngineView用于page的显示,基于QWebEnginePage就可实现无头浏览器。

auto page = new QWebEnginePage(this);
page->setUrl(QUrl("https://www.qt.io/"));
connect(page, &QWebEnginePage::loadFinished, this, [=](bool ok){
    qDebug() << __FUNCTION__ << "song" << "load is ok" << ok;
});

使用QWebEnginePage加载页面,页面加载成功后就可以做一些操作,如网络截图、爬虫、数据采集等。

QWebEnginePage支持QWebEngine内嵌浏览器相关的功能,具体可查看相关接口

1、获取网页相关信息

2、注入javascript

3、打印pdf

QML的WebEngineView没有像QWebEngineView把page的功能分开,所以WebEngineView不能实现无头浏览器的效果。

最后,需要注意的是,如果是在控制台程序中运行QWebEnginePage,main函数的应用程序类型必须是QApplication,使用QCoreApplication无法启动QWebEnginePage。

2、示例程序

mywebengineview.c

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

MyWebEngineView::MyWebEngineView(QWidget *parent) : QWebEngineView(parent)
{
    connect(this->page(),&QWebEnginePage::linkHovered,this,&MyWebEngineView::linkHovered);
    connect(&lessHeadPage,&QWebEnginePage::loadFinished,this,&MyWebEngineView::lessheadPagePrintfToPdf);
}

//这个函数应该是由底层的QWebEnginePage发起调用的,如果不想新建QWebEngineView,在这儿覆写。
QWebEngineView *MyWebEngineView::createWindow(QWebEnginePage::WebWindowType type)
{
    Q_UNUSED(type)

    //识别要无头浏览输出pdf
    if (newUrl.toString() == "https://www.baidu.com/s?wd=小米汽车&sa=fyb_n_homepage&rsv_dl=fyb_n_homepage&from=super&cl=3&tn=baidutop10&fr=top1000&rsv_idx=2&hisfilter=1" ||
        newUrl.toString() == "https://www.baidu.com/s?wd=国风浩荡+文脉赓续&sa=fyb_n_homepage&rsv_dl=fyb_n_homepage&from=super&cl=3&tn=baidutop10&fr=top1000&rsv_idx=2&hisfilter=1")
    {
        lessHeadPage.load(newUrl);
    }
    else
    {
        this->load(newUrl);
    }

    qDebug() << "createWindow url is :" <<this->url();

    return 0;
}

void MyWebEngineView::linkHovered(QString url)
{
    qDebug() << "linkHovered url is :" <<url;

    newUrl = QUrl(url);
}

//实现无头浏览输出pdf
void MyWebEngineView::lessheadPagePrintfToPdf(bool ok)
{
    Q_UNUSED(ok)
    lessHeadPage.printToPdf(QString("test.pdf"));
}

mywebengineview.h

#ifndef MYWEBENGINEVIEW_H
#define MYWEBENGINEVIEW_H
#include <QtWebEngineWidgets>

class MyWebEngineView : public QWebEngineView
{
    Q_OBJECT
public:
    explicit MyWebEngineView(QWidget *parent = nullptr);

    QWebEngineView * createWindow(QWebEnginePage::WebWindowType type) override;
    void linkHovered(QString url);
    void lessheadPagePrintfToPdf(bool ok);

private:
    QUrl newUrl;
    QWebEnginePage lessHeadPage;
};

#endif // MYWEBENGINEVIEW_H
标签: qt5 qml

本文转载自: https://blog.csdn.net/m0_37845735/article/details/139711107
版权归原作者 hurryddd 所有, 如有侵权,请联系我们删除。

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