extract information from a website using Qt?

Question

extract information from a website using Qt?

2.9k Views Asked by NPLS At 08 September 2013 at 20:07

I'd like extract the information in the b tag => 123456789

this is the HTML source :

<body>
       <div>
          <table>
               <tbody>
                     <tr>
                         <td class="myclass">
                               <b>123456789</b>
                         </td>
                     </tr>
              </tbody>
          </table>
       </div>
 </body>

So, I tried this :

void My_Test_Dialog::on_pushButton_clicked()
{


        QWebView *webview = new QWebView(parentWidget());

        webview->load(QUrl("http://www.esesese.com"));

        webview->show();

         // get HTML element information
        QWebElementCollection colls = webview->page()->mainFrame()->findAllElements("td.myclass b");



         foreach(QWebElement elemento, colls)
        {
                    ui->lineEdit_data->setText(elemento.toInnerXml());
        }
}

I have a form with a Button(call update) and a LineEdit, so if I click on the update button, the LineEdit should set the text 123456789 automatically. But my code doesn't work. The Text of the LineEdit remains empty.

I include this :

#include <QtWebKit>
#include <QtWebKitWidgets/QWebFrame>
#include <QWebView>

QT file.pro is :

QT += core gui
QT += network
QT += webkit
QT += webkitwidgets

Original Q&A

There are 1 best solutions below

**Erik** · Answer 1 · 2015-04-18T18:22:37.770000

As already mentioned you need to make sure that you wait long enough for the data in your QWebView to load.

You can do this (very simplistic) with something like this:

Define the webView as part of dialog class and also declare a slot that you can later connect to the signal of the web view

class My_Test_Dialog
{
public slots:

  // slot to read your data once you are finished
  void readPage(bool ok);

  // whatever else you did
private: 
  QWebView *webView;

}

Then e.g. in the constructor or elsewhere you can create the webView and connect its loadFinished() signal to the readPage() slot shown also in the class definition above

// create QWebview and connect its loadFinished signal to our slot 
webView = new QWebView(this);
QObject::connect(webView,SIGNAL(loadFinished(bool)), this, SLOT( readPage(bool) ) );

then in your on_pushButton_clicked() method you only load the page (and show the webview if that is what you need)

void My_Test_Dialog::on_pushButton_clicked()
{
  webView->load(QUrl("http://www.esesese.com"));
}

and then once the dialog finished loading the slot readData() will be automatically called and there you can simply do your read operation

void MyDialog::readPage(bool ok)
{
  // get HTML element information                                                                                                                                                                    
  QWebElementCollection colls = webView->page()->mainFrame()->findAllElements("td.myclass b");

  foreach(QWebElement elemento, colls)
    {
      lineEdit->setText(elemento.toInnerXml());
    }

}

Let me know if this helps.

extract information from a website using Qt?

There are 1 best solutions below

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