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Not able to use QList<Class> ComponentA (solved)

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  • A alvinNew

    I understand and realize that.
    But i do not want to hard-code the variable into ComponentA.
    How to make Component a QList.

    It's ok, i create a Component Template and move the contain variable into list before grabbing new data

    p3c0P Offline
    p3c0P Offline
    p3c0
    Moderators
    wrote on last edited by p3c0
    #4

    @alvinNew No need to hard code. You just need to store those values in an object of CComponent and add it to list. Define some setter methods in CComponent for storing values.

    class CComponent{
        public:
        QString ComponentID;
        QString ComponentType;
        ...
    
        void setComponentId(QString id) {
        ComponentID = id;
        }
    
        void setComponentType(QString type) {
        ComponentType = type;
        }
    };
    
    //Then during appending
    
    QList<CComponent> ComponentA;
    while (xmlGet.findNextAndDescend("Component"))
    {
          QString ComponentID = xmlGet.getAttributeString("ID","unknown");
          QString ComponentType = xmlGet.getAttributeString("Type","unknown");
    
           CComponent comp;
           comp.setComponentId(ComponentID); //store values
           comp.setComponentType(ComponentType); //store values
    
           //add that object to QList
           ComponentA.append(comp);
    }
    

    157

    A 1 Reply Last reply
    0
    • p3c0P p3c0

      @alvinNew No need to hard code. You just need to store those values in an object of CComponent and add it to list. Define some setter methods in CComponent for storing values.

      class CComponent{
          public:
          QString ComponentID;
          QString ComponentType;
          ...
      
          void setComponentId(QString id) {
          ComponentID = id;
          }
      
          void setComponentType(QString type) {
          ComponentType = type;
          }
      };
      
      //Then during appending
      
      QList<CComponent> ComponentA;
      while (xmlGet.findNextAndDescend("Component"))
      {
            QString ComponentID = xmlGet.getAttributeString("ID","unknown");
            QString ComponentType = xmlGet.getAttributeString("Type","unknown");
      
             CComponent comp;
             comp.setComponentId(ComponentID); //store values
             comp.setComponentType(ComponentType); //store values
      
             //add that object to QList
             ComponentA.append(comp);
      }
      
      A Offline
      A Offline
      alvinNew
      wrote on last edited by
      #5

      @p3c0

      Many thanks, i can learn alot from your simple coding.

      p3c0P 1 Reply Last reply
      0
      • A alvinNew

        @p3c0

        Many thanks, i can learn alot from your simple coding.

        p3c0P Offline
        p3c0P Offline
        p3c0
        Moderators
        wrote on last edited by p3c0
        #6

        @alvinNew You're Welcome :) Happy Coding ...
        Also use ``` (3 backticks), key just above the tab button on keyboard for posting code blocks.

        157

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        • H Offline
          H Offline
          houmingc
          wrote on last edited by
          #7

          My code is in pastebin, http://pastebin.com/JwKjfW0b
          Like to ask how to read out the data in the class ( CComponent )

          p3c0P 1 Reply Last reply
          0
          • H houmingc

            My code is in pastebin, http://pastebin.com/JwKjfW0b
            Like to ask how to read out the data in the class ( CComponent )

            p3c0P Offline
            p3c0P Offline
            p3c0
            Moderators
            wrote on last edited by
            #8

            @houmingc You will need to write getter methods as well which will return the values stored in those variables.

            157

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            • H Offline
              H Offline
              houmingc
              wrote on last edited by houmingc
              #9

              Code below is not working although no compiler error

              QList<CComponent> list;
              
                 QListIterator<CComponent> i(list);
                 while(i.hasNext()){
                     qDebug()<<"xxxx is "<<ComponentTemplate.ComponentX;
                 }
              p3c0P 2 Replies Last reply
              0
              • H houmingc

                Code below is not working although no compiler error

                QList<CComponent> list;
                
                   QListIterator<CComponent> i(list);
                   while(i.hasNext()){
                       qDebug()<<"xxxx is "<<ComponentTemplate.ComponentX;
                   }
                p3c0P Offline
                p3c0P Offline
                p3c0
                Moderators
                wrote on last edited by
                #10

                @houmingc You are doing it wrong. First create some getter methods as said earlier. Then you need to cast the item to CComponent in the loop and access the getter methods to get the values stored in it.

                157

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                • H houmingc

                  Code below is not working although no compiler error

                  QList<CComponent> list;
                  
                     QListIterator<CComponent> i(list);
                     while(i.hasNext()){
                         qDebug()<<"xxxx is "<<ComponentTemplate.ComponentX;
                     }
                  p3c0P Offline
                  p3c0P Offline
                  p3c0
                  Moderators
                  wrote on last edited by p3c0
                  #11

                  @houmingc Something like this

                  //CComponent class
                  
                  void CComponent::setId(QString id)
                  {
                      m_id = id;
                  }
                  
                  QString CComponent::getId()
                  {
                      return m_id;
                  }
                  
                  QString m_id, m_type;
                  

                  then to access after appending to list

                  QList<CComponent *> m_list;
                  ...
                  
                  CComponent *ca = new CComponent;
                  ca->setId("one");
                  ca->setType("big");
                  ...
                  
                  m_list.append(ca);
                  
                  ...
                  
                  QListIterator<CComponent*> i(m_list);
                  while (i.hasNext()) {
                      CComponent *comp = qobject_cast<CComponent*>(i.next()); //qobject_cast - if uses QObject
                      qDebug() << comp->getId() << comp->getType();
                  }
                  
                  

                  157

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                  • H Offline
                    H Offline
                    houmingc
                    wrote on last edited by houmingc
                    #12

                    i have an error at cast object
                    error: no matching function for call to 'qobject_cast(CComponent* const&)'
                    CComponent comp = qobject_cast<CComponent>(i.next());

                    p3c0P 1 Reply Last reply
                    0
                    • H Offline
                      H Offline
                      houmingc
                      wrote on last edited by
                      #13

                      qDebug() << ComponentList[0].GetComponentHeight(); // why accessing ComponentList array return error?

                      1 Reply Last reply
                      0
                      • H houmingc

                        i have an error at cast object
                        error: no matching function for call to 'qobject_cast(CComponent* const&)'
                        CComponent comp = qobject_cast<CComponent>(i.next());

                        p3c0P Offline
                        p3c0P Offline
                        p3c0
                        Moderators
                        wrote on last edited by
                        #14

                        @houmingc said:

                        i have an error at cast object
                        error: no matching function for call to 'qobject_cast(CComponent* const&)'
                        CComponent comp = qobject_cast<CComponent>(i.next());

                        Try it exactly how I have posted earlier in the example.

                        qDebug() << ComponentList[0].GetComponentHeight(); // why accessing ComponentList array return error?

                        What error ? ComponentList is a QList, right ?

                        157

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                        • H Offline
                          H Offline
                          houmingc
                          wrote on last edited by houmingc
                          #15

                          I got the each component display. Thanks.
                          No Casting needed.
                          How to get 3rd item of the class? i am now wondering if QList should be used instead of QLinkedList

                             QLinkedList<CComponent>::iterator iterator;
                              for(iterator=ComponentList.begin();iterator != ComponentList.end(); iterator ++)
                              {
                                  qDebug()<<iterator->GetComponentAspectRatio()<<endl;
                              }
                          p3c0P 1 Reply Last reply
                          0
                          • H houmingc

                            I got the each component display. Thanks.
                            No Casting needed.
                            How to get 3rd item of the class? i am now wondering if QList should be used instead of QLinkedList

                               QLinkedList<CComponent>::iterator iterator;
                                for(iterator=ComponentList.begin();iterator != ComponentList.end(); iterator ++)
                                {
                                    qDebug()<<iterator->GetComponentAspectRatio()<<endl;
                                }
                            p3c0P Offline
                            p3c0P Offline
                            p3c0
                            Moderators
                            wrote on last edited by p3c0
                            #16

                            @houmingc Casting will be needed if you use QListIterator.

                            QList<CComponent*> m_list;
                            
                            CComponent *ca = new CComponent;
                            ca->setId("one");
                            ca->setType("big");
                            
                            m_list.append(ca);
                            
                            QListIterator<CComponent*> i(m_list);
                            while (i.hasNext()) {
                                CComponent *comp = qobject_cast<CComponent*>(i.next()); //qobject_cast - if uses QObject
                                qDebug() << comp->getId() << comp->getType(); //access using QListIterator
                            }
                            
                            /*-------------------------------------------------------------*/
                            
                            qDebug() << m_list[0]->getType() << m_list[0]->getId(); //no need to cast
                            

                            157

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