read a write a XML file withe QXmlStreamWriter/QXmlStreamReader

Alex42 · 28 Jul 2021, 10:50

Hello Every One,
1 - I created a XML file using QXmlStreamWriter class , the file containe the data of my user interface ( lineEdit) ( when we click on the Save button)
2- and now i wante to load the data (when we click on the load button),
i'm trying to load the data using a QXmlStreamReader, but without success ,
may be some one can helpe me
thanks in advance

Here is the XML file writing code.
<<

QString sFileXMLName = QFileDialog::getSaveFileName(this, tr(" Xml File"), "C:/ ...", tr("Fichier Xml (*.xml)"));

     QFile fFileXML(sFileXMLName);

  
     if(!fFileXML.open(QFile::WriteOnly | QFile::Text))
         return;

     QXmlStreamWriter xmlWriter(&fFileXML);

     xmlWriter.setAutoFormatting(true);

     //the norme of codification  XML file 
     xmlWriter.writeStartDocument();

     //Element root  of xml file 
     xmlWriter.writeStartElement("Calib");
     

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui->lineEdit->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_9 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_2 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_10 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_3 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_11 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_4 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_12 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_5 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_13 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_6 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_14 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_7 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_15 ->text());
         xmlWriter.writeEndElement();

         xmlWriter.writeStartElement("CalibPt");
         xmlWriter.writeTextElement("conv", ui-> lineEdit_8 ->text());
         xmlWriter.writeTextElement("calib",ui-> lineEdit_16 ->text());
         xmlWriter.writeEndElement();

         //close Element
         xmlWriter.writeEndElement();

     //close element  "Root calib"
     xmlWriter.writeEndElement();

     //Finalised the  XML  file 
     xmlWriter.writeEndDocument();

     //close the xml file XML to save   the document
     fFileXML.close();

}

mrjj · wrote on 28 Jul 2021, 09:37

Hi
Did you see this one?
https://www.walletfox.com/course/qxmlstreamreaderexample.php

It explains it pretty well.

VRonin · A Alex42 28 Jul 2021, 09:31

@Alex42 said in read a write a XML file withe QXmlStreamWriter/QXmlStreamReader:

i'm trying to load the data using a QXmlStreamReader, but without success ,

Show this part of the code please

Alex42 · wrote on 28 Jul 2021, 12:16

@mrjj , thank you for your response , i found the exemple very usfule ,
@VRonin, i resolved the probleme , juste may program it's note optimized , becouse i have a lote of condition ,

thanks anyways

for the curios

QString sFilePath = QFileDialog::getOpenFileName(this, tr("Open XML File ..."), "E:/", tr("XMLFile (*.xml)"));

   if(sFilePath.isEmpty())
   {
       QMessageBox::critical(this, tr("Open File XML"), tr("the file is empty !"));
       return;
   }


   QFileInfo fileInfo(sFilePath);
   QString sFileXmlName = fileInfo.fileName();

   // XML object
   QXmlStreamReader reader;
   //Fichier XML
   QFile fFileXml(sFilePath);

   //open XML on red only 
   if(!fFileXml.open(QFile::ReadOnly | QFile::Text))
   {
       QMessageBox::critical(this, tr("Open File XML"), tr("the file is not open  !"), QMessageBox::Ok);
       return;
   }

   if (reader.readNextStartElement()) {
           if (reader.name() == "Calib"){
               while(reader.readNextStartElement()){
                   if(reader.name() == "CalibPt"){
                       while(reader.readNextStartElement()){
                           if(reader.name() == "calib"){
                              QString s = reader.readElementText();
                              ui->lineEdit_19->setText(s);
                           }

                           else if(reader.name() == "conv_"){
                                                            QString  s = reader.readElementText();
                                                             ui->spinBox_1->setValue(s. toInt());
                                                          }

                           else if(reader.name() == "conv_1"){
                                                             QString s = reader.readElementText();
                                                             ui->lineEdit->setText(s);
                                                          }
                            else if(reader.name() == "calib_1"){
                                                               QString s = reader.readElementText();
                                                               ui->lineEdit_9->setText(s);
                                                           }

                           else if(reader.name() == "conv_2"){
                                                            QString  s = reader.readElementText();
                                                             ui->lineEdit_2->setText(s);
                                                          }

                           else if(reader.name() == "calib_2"){
                                                             QString s = reader.readElementText();
                                                             ui->lineEdit_10->setText(s);
                                                          }
                            else if(reader.name() == "conv_3"){
                                                               QString s = reader.readElementText();
                                                               ui->lineEdit_3->setText(s);
                                                           }
                           else if(reader.name() == "calib_3"){
                                                            QString  s = reader.readElementText();
                                                             ui->lineEdit_11->setText(s);
                                                          }

                           else if(reader.name() == "conv_4"){
                                                             QString s = reader.readElementText();
                                                             ui->lineEdit_4->setText(s);
                                                          }
                                                          else if(reader.name() == "calib_4"){
                                                               QString s = reader.readElementText();
                                                               ui->lineEdit_12->setText(s);
                                                           }


                           else if(reader.name() == "conv_5"){
                                                            QString  s = reader.readElementText();
                                                             ui->lineEdit_5->setText(s);
                                                          }

                           else if(reader.name() == "calib_5"){
                                                             QString s = reader.readElementText();
                                                             ui->lineEdit_13->setText(s);
                                                          }
                                                          else if(reader.name() == "conv_6"){
                                                               QString s = reader.readElementText();
                                                               ui->lineEdit_6->setText(s);
                                                           }

                           else if(reader.name() == "calib_6"){
                                                            QString  s = reader.readElementText();
                                                             ui->lineEdit_14->setText(s);
                                                          }

                           else if(reader.name() == "conv_7"){
                                                             QString s = reader.readElementText();
                                                             ui->lineEdit_7->setText(s);
                                                          }
                                                          else if(reader.name() == "calib_7"){
                                                               QString s = reader.readElementText();
                                                               ui->lineEdit_15->setText(s);
                                                           }
                           else if(reader.name() == "conv_8"){
                                                            QString  s = reader.readElementText();
                                                             ui->lineEdit_8->setText(s);
                                                          }

                           else if(reader.name() == "calib_8"){
                                                             QString s = reader.readElementText();
                                                             ui->lineEdit_16->setText(s);
                                                          }


                           else
                               reader.skipCurrentElement();
                       }
                   }
                   else
                       reader.skipCurrentElement();
               }
           }
           else
               reader.raiseError(QObject::tr("."));
   }

I have to change the names of the subchild, otherwise it will not work.