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

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  • A Offline
    A Offline
    alvinNew
    wrote on last edited by alvinNew
    #3

    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 1 Reply Last reply
    0
    • 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

          1 Reply Last reply
          0
          • 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

              1 Reply Last reply
              0
              • 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

                  1 Reply 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 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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                    0
                    • 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

                          1 Reply Last reply
                          0
                          • 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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