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Searching in QFile which has source of webpage

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  • C Offline
    C Offline
    CreMindES
    wrote on last edited by
    #4

    Gerof is right I think, I would use QTextStream too...

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    • G Offline
      G Offline
      giesbert
      wrote on last edited by
      #5

      If you look at the given links ("QTextStream":http://doc.qt.nokia.com/latest/qtextstream.html#details ) there is a description, how to read a file to a QString.

      you can also read using QFile directly. From the docu:

      @
      QFile file("in.txt");
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
      return;

      QTextStream in(&file);
      while (!in.atEnd()) {
          QString line = in.readLine();
          process_line(line);
      }
      

      @

      or

      @
      QFile file("in.txt");
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
      return;

       while (!file.atEnd()) {
           QByteArray line = file.readLine();
           process_line(line);
       }
      

      @

      or

      @
      QFile file("in.txt");
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
      return;

      QTextStream in(&file);
      QString str = in.readAll();
      

      @

      For more information on that, I propose a look at the Qt documentation (link in the top right corner, called DOC) :-)

      Nokia Certified Qt Specialist.
      Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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      • G Offline
        G Offline
        giesbert
        wrote on last edited by
        #6

        [quote author="roosaw" date="1293738563"]First method (SAX, DOM) doesn't work. Example programs gives error (unknown char)
        ...
        ?[/quote]

        What type does your data has? is it XML? is it plain text?

        Nokia Certified Qt Specialist.
        Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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        • R Offline
          R Offline
          roosaw
          wrote on last edited by
          #7

          Can you tell me how to convert whole file into QTextStream?
          I've done something like this (after closing file):

          @QFile file("plik.xml");
          if (file.open(QFile::ReadWrite)) {
          QTextStream out(&plik);
          out.readAll();
          // out << "Result: " << qSetFieldWidth(10) << left << 3.14 << 2.7;
          // writes "Result: 3.14 2.7 "
          }
          file.close();@

          From documentation i know that it convert out to QString. Now how can i seek a phrase in there?

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          • R Offline
            R Offline
            roosaw
            wrote on last edited by
            #8

            [quote author="Gerolf" date="1293739383"]
            [quote author="roosaw" date="1293738563"]First method (SAX, DOM) doesn't work. Example programs gives error (unknown char)
            ...
            ?[/quote]

            What type does your data has? is it XML? is it plain text?[/quote]

            I downloaded page with:
            @ file= new QFile("plik.xml", this);
            file->open(QIODevice::ReadWrite);
            http = new QHttp(this);
            http->setHost("addressofpage.com");
            http->get("/pathtopage.html", file);@
            but i can look at it in text editor so... i think it is a plain text.

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            • G Offline
              G Offline
              giesbert
              wrote on last edited by
              #9

              @
              QFile file("in.txt");
              if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
              return;

              QTextStream in(&file);
              QString str = in.readAll();
              @

              Then use QString functions

              look at the docu, it is really good

              something with find/search/indexOf...

              Nokia Certified Qt Specialist.
              Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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              • B Offline
                B Offline
                BlackDante
                wrote on last edited by
                #10

                [quote author="roosaw" date="1293739634"]Can you tell me how to convert whole file into QTextStream?
                I've done something like this (after closing file):

                @QFile file("plik.xml");
                if (file.open(QFile::ReadWrite)) {
                QTextStream out(&plik);
                out.readAll();
                // out << "Result: " << qSetFieldWidth(10) << left << 3.14 << 2.7;
                // writes "Result: 3.14 2.7 "
                }
                file.close();@

                From documentation i know that it convert out to QString. Now how can i seek a phrase in there?
                [/quote]
                You can first convert QFile into QString, example:
                @QFile file(plik);
                QString item;
                file.open(QFile::ReadOnly);
                char buff[255];
                while (!file.atEnd())
                {
                file.readLine(buff, sizeof(buff));
                item.append(buff);
                }@
                and QString you can convert to QTextStream
                @QTextStream text = new QTextStream(item,QIODevice::ReadOnly);@

                or you can even in QString find. You have function "indexOF":http://doc.qt.nokia.com/4.7/qstring.html#indexOf , who returns you position of looking word.

                sorry for my broken english :)

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                • G Offline
                  G Offline
                  giesbert
                  wrote on last edited by
                  #11

                  First read the file into a QString, change the QString and write the string back to the file.

                  Nokia Certified Qt Specialist.
                  Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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                  • R Offline
                    R Offline
                    roosaw
                    wrote on last edited by
                    #12

                    [quote author="BlackDante" date="1293741181"]
                    You can first convert QFile into QString, example:
                    @QFile file(plik);
                    QString item;
                    file.open(QFile::ReadOnly);
                    char buff[255];
                    while (!file.atEnd())
                    {
                    file.readLine(buff, sizeof(buff));
                    item.append(buff);
                    }@[/quote]
                    Ok, it works :) I mean... compiling...
                    Now how can i search specific string in that QString (someting like item.seek("I/'m seeking this string");
                    Is there is something like this?
                    I found that:
                    http://doc.qt.nokia.com/latest/qstring.html#compare-5
                    but it compare only lenght of two strings...

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                    • G Offline
                      G Offline
                      giesbert
                      wrote on last edited by
                      #13

                      [quote author="Gerolf" date="1293741140"]@
                      QFile file("in.txt");
                      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
                      return;

                      QTextStream in(&file);
                      QString str = in.readAll();
                      @

                      Then use QString functions

                      look at the docu, it is really good

                      something with find/search/indexOf...[/quote]

                      If you read all posts, you perhaps find the solution :-)

                      "QString::indexOf":http://doc.qt.nokia.com/latest/qstring.html#indexOf

                      Nokia Certified Qt Specialist.
                      Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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                      0
                      • G Offline
                        G Offline
                        goetz
                        wrote on last edited by
                        #14

                        If you want to read the complete file into a string readAll() is your friend:

                        @
                        QFile file("mytextfile.txt");
                        if(!file.open(QIODevice::ReadOnly))
                        qFatal() << "File cannot be opened";

                        QTextStream ts(file);
                        QString fileContent = ts.readAll();
                        file.close();
                        @

                        If you read strings from a file it's always better to use QTextStream, as it does the proper decoding (UTF-8 etc.) for you.

                        http://www.catb.org/~esr/faqs/smart-questions.html

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