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Pass QXmlStreamReader Instance to Class

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  • R Offline
    R Offline
    RRRitchey
    wrote on last edited by
    #1

    I am trying to read an XML document using QXmlStreamReader. I am running into issues when I try to pass a pointer to the reader to other classes. I create an instance of the reader in one class. That class reads the XML until it comes to a block defining a new class. I create and instance of the new class and then call a function in that class to continue reading the XML specific for it. For instance:

    @void SF_UnitClass::ReadModes()
    {
    Q_ASSERT(XML.isStartElement() && XML.name() == MODES);
    NumModes = XML.attributes().value(COUNT).toInt();
    while (XML.readNextStartElement())
    {
    if (XML.name() == MODE)
    {
    ModeClass* pMode = new ModeClass(this);
    ModeList += XML.attributes().value(ID).toString();
    pMode->ReadXML(&XML);
    {
    }
    }
    else
    {
    XML.raiseError(QObject::tr("Something other than Mode block encountered in Modes block"));
    }
    }
    }
    @
    This works part way through the file but then the reader seems to forget what level its at. readNextStartElement() returns false when it shouldn't. The file is fine as I took a TreeWidget example and customized it for my use and it reads the whole file just fine. I am thinking that for some reason I cannot pass a pointer to the reader to another classes function to continue reading the XML?

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    • dheerendraD Offline
      dheerendraD Offline
      dheerendra
      Qt Champions 2022
      wrote on last edited by
      #2

      You can pass. We use everywhere. You can pass. Some of the sample methods we have are

      @ void readCompanyNew(QXmlStreamReader *par);
      void readProjectNew(QXmlStreamReader *par);

      I am calling them like
      readCompanyNew(&parser);
      readProjectNew(&parser);

      @

      Dheerendra
      @Community Service
      Certified Qt Specialist
      http://www.pthinks.com

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      • R Offline
        R Offline
        RRRitchey
        wrote on last edited by
        #3

        Thanks, that is good to know. I will keep digging into this then.

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        • dheerendraD Offline
          dheerendraD Offline
          dheerendra
          Qt Champions 2022
          wrote on last edited by
          #4

          if you want the complete sample, drop email to me. I will send you the complete solution dump.

          Dheerendra
          @Community Service
          Certified Qt Specialist
          http://www.pthinks.com

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          • R Offline
            R Offline
            RRRitchey
            wrote on last edited by
            #5

            Thanks but I think its in my code somewhere but I am missing it. I am finding it hard to debug because I don't know why readNextStartElement() is returning a false where it should not. Here is a sample of my XML. My code reads all the <Channel> blocks fine. It then it reads the <Servos> start element and the first <Servo> block fine but then gets a false from readNextStartElement() when it should read the next <Servo> start element and goes all the way back up to my Mode loop. Just need to figure out why it does not read the second servo block. Thanks.

            @<?xml version="1.0" encoding="UTF-8"?>
            <!DOCTYPE xml>
            <SmartFlyUnit version="1.0">
            <UnitName>PowerExpander Eq10E</UnitName>
            <UnitCode>PE-5</UnitCode>
            <UnitID>1</UnitID>
            <MinRev>1.0</MinRev>
            <MaxRev>1.9</MaxRev>
            <Servos>36</Servos>
            <Outputs>32</Outputs>
            <UnitMode>Chan</UnitMode>
            <Modes Count="2">
            <Mode ID="Chan">
            <Receivers>1</Receivers>
            <Channels Count="10">
            <Channel ID="0">
            <UserName></UserName>
            <EndPtHold>Off</EndPtHold>
            <ServoPri>Off</ServoPri>
            </Channel>
            <Channel ID="1">
            <UserName></UserName>
            <EndPtHold>Off</EndPtHold>
            <ServoPri>Off</ServoPri>
            </Channel>
            </Channels>
            <Servos Count="36">
            <Servo ID="0">
            <Offset>0</Offset>
            <PosFact>1.0000</PosFact>
            <NegFact>1.0000</NegFact>
            <Reverse>Off</Reverse>
            <SecServo>0xFF</SecServo>
            <Unit>0xFF</Unit>
            <Ser1>0xFF</Ser1>
            <Ser2>0xFF</Ser2>
            <Ser3>0xFF</Ser3>
            </Servo>
            <Servo ID="1">
            <Offset>0</Offset>
            <PosFact>1.0000</PosFact>
            <NegFact>1.0000</NegFact>
            <Reverse>Off</Reverse>
            <SecServo>0xFF</SecServo>
            <Unit>0xFF</Unit>
            <Ser1>0xFF</Ser1>
            <Ser2>0xFF</Ser2>
            <Ser3>0xFF</Ser3>
            </Servo>
            </Servos>
            </Mode>
            </Modes>
            <MCUs Count="1">
            <MCU ID="0">
            <FileName>/PE-5/PE-5_M0_1_00.sffw</FileName>
            </MCU>
            </MCUs>
            <FPGAs Count="1">
            <FPGA ID="0">
            <Configs Count="2">
            <Config ID="0">
            <FileName>/PE-5/PE-5_F0C0_1_00.sffw</FileName>
            </Config>
            <Config ID="1">
            <FileName>/PE-5/PE-5_F0C1_1_00.sffw</FileName>
            </Config>
            </Configs>
            </FPGA>
            </FPGAs>
            </SmartFlyUnit>
            @

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            • R Offline
              R Offline
              RRRitchey
              wrote on last edited by
              #6

              OK, solved. My inexperience in dealing with the XML reader. I missed a case in my switch statement which caused an item to be missed and put things out of sequence. I need to add a default with a skipCurrentElement or raise an error. Thanks for all the feedback, it helped me catch this.

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