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updating elements in a repeater?

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  • kshegunovK kshegunov
    typedef QVector<Bottle> Bottles;
    

    If Bottle is derived from QObject you can't keep it directly in a vector (can't copy the objects). You need to keep Bottle * there.

    mzimmersM Offline
    mzimmersM Offline
    mzimmers
    wrote on last edited by
    #30

    @kshegunov ah. OK, thanks for that. I'll look into making that change, and will report back.

    1 Reply Last reply
    0
    • mzimmersM Offline
      mzimmersM Offline
      mzimmers
      wrote on last edited by
      #31

      I've changed my QVector to pointers (seems to be working).

      I think I see why my example is so confusing -- in my Bottle Repeater, I'm using a QML ListModel. This ListModel only contains UI-specific information (position, size). Additional informationmust come from an object (ReagentManager) that is exposed via a call to setContextProperty().

      So: do I need to change my model to the instance of ReagentManager, and find another way to access the information currently in my ListModel? Or is there a more clever way to do this?

      Thanks...

      kshegunovK 1 Reply Last reply
      0
      • mzimmersM mzimmers

        I've changed my QVector to pointers (seems to be working).

        I think I see why my example is so confusing -- in my Bottle Repeater, I'm using a QML ListModel. This ListModel only contains UI-specific information (position, size). Additional informationmust come from an object (ReagentManager) that is exposed via a call to setContextProperty().

        So: do I need to change my model to the instance of ReagentManager, and find another way to access the information currently in my ListModel? Or is there a more clever way to do this?

        Thanks...

        kshegunovK Offline
        kshegunovK Offline
        kshegunov
        Moderators
        wrote on last edited by
        #32

        @mzimmers said in updating elements in a repeater?:

        So: do I need to change my model to the instance of ReagentManager, and find another way to access the information currently in my ListModel? Or is there a more clever way to do this?

        Why do you need the ListModel is the question now. Pass the objects vector from the context property (i.e the bottleManager object) directly to the repeater.

        Read and abide by the Qt Code of Conduct

        mzimmersM 1 Reply Last reply
        0
        • kshegunovK kshegunov

          @mzimmers said in updating elements in a repeater?:

          So: do I need to change my model to the instance of ReagentManager, and find another way to access the information currently in my ListModel? Or is there a more clever way to do this?

          Why do you need the ListModel is the question now. Pass the objects vector from the context property (i.e the bottleManager object) directly to the repeater.

          mzimmersM Offline
          mzimmersM Offline
          mzimmers
          wrote on last edited by mzimmers
          #33

          @kshegunov said in updating elements in a repeater?:

          Why do you need the ListModel is the question now. Pass the objects vector from the context property (i.e the bottleManager object) directly to the repeater.

          I'm using the list model for UI-specific information:

            ListModel {
              id: bottleModel
          
              ListElement {
                // position 1
                x: 400
                y: 17
                height: 75
                width: 75
              }
              ...
          

          I could probably put this data in arrays in QML. As I mentioned, I'd prefer not to put it into my C++ as it's purely UI data.

          From my definition of the ReagentManager class:

          class ReagentManager : public QObject {
            Q_OBJECT
           public:
            explicit ReagentManager(QObject *parent = nullptr);
            Bottles m_bottleList;
            Q_PROPERTY(Bottles bottleList MEMBER m_bottleList)
            ...
          

          And in my QML:

              function updateBottles() {
                var modelSize = bottleModel.count
                var i
                var volume
          
                for (i = 0; i < modelSize; ++i) {
                  volume = reagentManager.bottleList[i].volume
              ...
          

          I'm getting an error "TypeError: Cannot read property '0' of undefined." Is my syntax wrong, or am I still not understanding how to access the property?

          Thanks...

          EDIT: looking at the QML Debugger Console, I see this message:

          QMetaProperty::read: Unable to handle unregistered datatype 'Bottles' for property 'ReagentManager::bottleList'
          
          kshegunovK 1 Reply Last reply
          0
          • mzimmersM mzimmers

            @kshegunov said in updating elements in a repeater?:

            Why do you need the ListModel is the question now. Pass the objects vector from the context property (i.e the bottleManager object) directly to the repeater.

            I'm using the list model for UI-specific information:

              ListModel {
                id: bottleModel
            
                ListElement {
                  // position 1
                  x: 400
                  y: 17
                  height: 75
                  width: 75
                }
                ...
            

            I could probably put this data in arrays in QML. As I mentioned, I'd prefer not to put it into my C++ as it's purely UI data.

            From my definition of the ReagentManager class:

            class ReagentManager : public QObject {
              Q_OBJECT
             public:
              explicit ReagentManager(QObject *parent = nullptr);
              Bottles m_bottleList;
              Q_PROPERTY(Bottles bottleList MEMBER m_bottleList)
              ...
            

            And in my QML:

                function updateBottles() {
                  var modelSize = bottleModel.count
                  var i
                  var volume
            
                  for (i = 0; i < modelSize; ++i) {
                    volume = reagentManager.bottleList[i].volume
                ...
            

            I'm getting an error "TypeError: Cannot read property '0' of undefined." Is my syntax wrong, or am I still not understanding how to access the property?

            Thanks...

            EDIT: looking at the QML Debugger Console, I see this message:

            QMetaProperty::read: Unable to handle unregistered datatype 'Bottles' for property 'ReagentManager::bottleList'
            
            kshegunovK Offline
            kshegunovK Offline
            kshegunov
            Moderators
            wrote on last edited by kshegunov
            #34

            @mzimmers said in updating elements in a repeater?:

            I could probably put this data in arrays in QML. As I mentioned, I'd prefer not to put it into my C++ as it's purely UI data.

            You already have this data in the c++, you feed it to the JS engine as far as I can see. I'd just tie the cpp backend to the UI stuff and not mess with any intermediate stuff, much less using explicit JS code.

            Basically like this:

            Column {
                  Repeater {
                    model: reagentManager.bottleList //< This being a property that holds the list of bottles
                    Bottle {
                      cellX: modelData.x
                      cellY: modelData.y //< Or use some other value, or nothing, however you decide to do it
                      ...
                      volume: modelData.volume //< This binds to the property of the QObject, so when the C++ changes value this updates
                      ...
                    }
                 ...
            }
            

            @mzimmers said in updating elements in a repeater?:

            I'm getting an error "TypeError: Cannot read property '0' of undefined." Is my syntax wrong, or am I still not understanding how to access the property?
            Thanks...
            EDIT: looking at the QML Debugger Console, I see this message:

            From the method:

            https://doc.qt.io/qt-5/qqmllistproperty.html
            or
            you return QList<QObject *>
            or
            you return a QVariantList() << bottle1 << bottle2

            ... different possibilities.

            Read and abide by the Qt Code of Conduct

            1 Reply Last reply
            1
            • mzimmersM Offline
              mzimmersM Offline
              mzimmers
              wrote on last edited by mzimmers
              #35

              I've changed my typedef from a QVector to a QList:

              typedef QList<Bottle *> Bottles;
              

              My C++ looks like this (stripped down) now:

              struct Bottle : public QObject {
                Q_OBJECT
                Q_PROPERTY(quint32 volume MEMBER m_volume)
               public:
                quint32 m_volume;                // amount in bottle (in uL)
               signals:
                void volumeChanged(quint32 m_volume);
              };
              typedef QList<Bottle *> Bottles;
              
              class ReagentManager : public QObject {
                Q_OBJECT
               private:
                Bottles m_bottleList;
               public:
                Q_INVOKABLE Bottles bottleList() { return m_bottleList; }
                void bottleListChanged();
              };
              

              And this line in QML:

                      volume = reagentManager.bottleList[i].volume
              

              Now produces this error:

              qrc:/qml/Rack.qml:194: TypeError: Cannot read property 'volume' of undefined 
              

              So...I've kicked the can a little further down the street, but I'm not home yet. It seems that the QML can now access the QList (agree?), but not its properties. Do I need a getter for this? I thought the idea of getting the properties working properly was to eliminate the need for the getters/setters.

              ODБOïO 1 Reply Last reply
              0
              • mzimmersM mzimmers

                I've changed my typedef from a QVector to a QList:

                typedef QList<Bottle *> Bottles;
                

                My C++ looks like this (stripped down) now:

                struct Bottle : public QObject {
                  Q_OBJECT
                  Q_PROPERTY(quint32 volume MEMBER m_volume)
                 public:
                  quint32 m_volume;                // amount in bottle (in uL)
                 signals:
                  void volumeChanged(quint32 m_volume);
                };
                typedef QList<Bottle *> Bottles;
                
                class ReagentManager : public QObject {
                  Q_OBJECT
                 private:
                  Bottles m_bottleList;
                 public:
                  Q_INVOKABLE Bottles bottleList() { return m_bottleList; }
                  void bottleListChanged();
                };
                

                And this line in QML:

                        volume = reagentManager.bottleList[i].volume
                

                Now produces this error:

                qrc:/qml/Rack.qml:194: TypeError: Cannot read property 'volume' of undefined 
                

                So...I've kicked the can a little further down the street, but I'm not home yet. It seems that the QML can now access the QList (agree?), but not its properties. Do I need a getter for this? I thought the idea of getting the properties working properly was to eliminate the need for the getters/setters.

                ODБOïO Offline
                ODБOïO Offline
                ODБOï
                wrote on last edited by
                #36

                @mzimmers said in updating elements in a repeater?:

                volume = reagentManager.bottleList[i].volume

                bottleList is a function but you are accessing like an array

                volume = reagentManager.bottleList()[i]

                mzimmersM 1 Reply Last reply
                1
                • ODБOïO ODБOï

                  @mzimmers said in updating elements in a repeater?:

                  volume = reagentManager.bottleList[i].volume

                  bottleList is a function but you are accessing like an array

                  volume = reagentManager.bottleList()[i]

                  mzimmersM Offline
                  mzimmersM Offline
                  mzimmers
                  wrote on last edited by
                  #37

                  @LeLev said in updating elements in a repeater?:

                  @mzimmers said in updating elements in a repeater?:

                  volume = reagentManager.bottleList[i].volume

                  bottleList is a function but you are accessing like an array

                  volume = reagentManager.bottleList()[i]

                  Thanks...I thought this would work:

                   volume = reagentManager.bottleList()[i].volume
                  

                  But I get this error:

                  Error: Unknown method return type: Bottles
                  

                  This goes back to what kshegunov was talking about earlier, but I thought I'd fixed this by changing from a QVector to a QList:

                  typedef QList<Bottle *> Bottles;
                  
                  class ReagentManager : public QObject {
                    Q_OBJECT
                   public:
                    Q_INVOKABLE Bottles bottleList() { return m_bottleList; }
                  

                  I'm still missing something...

                  ODБOïO 1 Reply Last reply
                  0
                  • mzimmersM mzimmers

                    @LeLev said in updating elements in a repeater?:

                    @mzimmers said in updating elements in a repeater?:

                    volume = reagentManager.bottleList[i].volume

                    bottleList is a function but you are accessing like an array

                    volume = reagentManager.bottleList()[i]

                    Thanks...I thought this would work:

                     volume = reagentManager.bottleList()[i].volume
                    

                    But I get this error:

                    Error: Unknown method return type: Bottles
                    

                    This goes back to what kshegunov was talking about earlier, but I thought I'd fixed this by changing from a QVector to a QList:

                    typedef QList<Bottle *> Bottles;
                    
                    class ReagentManager : public QObject {
                      Q_OBJECT
                     public:
                      Q_INVOKABLE Bottles bottleList() { return m_bottleList; }
                    

                    I'm still missing something...

                    ODБOïO Offline
                    ODБOïO Offline
                    ODБOï
                    wrote on last edited by
                    #38

                    @mzimmers said in updating elements in a repeater?:

                    I'm still missing something...

                    i would return a QVariantList to qml instead of the QList<Bottle *>

                    mzimmersM 1 Reply Last reply
                    1
                    • ODБOïO ODБOï

                      @mzimmers said in updating elements in a repeater?:

                      I'm still missing something...

                      i would return a QVariantList to qml instead of the QList<Bottle *>

                      mzimmersM Offline
                      mzimmersM Offline
                      mzimmers
                      wrote on last edited by
                      #39

                      @LeLev OK, but...how do I do that? I can't just cast it. Do I have to change my Bottles typedef?

                      Thanks...

                      ODБOïO 1 Reply Last reply
                      0
                      • mzimmersM mzimmers

                        @LeLev OK, but...how do I do that? I can't just cast it. Do I have to change my Bottles typedef?

                        Thanks...

                        ODБOïO Offline
                        ODБOïO Offline
                        ODБOï
                        wrote on last edited by
                        #40

                        Q_INVOKABLE QVariant bottleList() { return QVariant::fromValue(m_bottleList); }

                        mzimmersM 1 Reply Last reply
                        2
                        • mzimmersM mzimmers

                          I know, I'm doing a lousy job of explaining this. in C++:

                          typedef QVector<Bottle> Bottles;
                          class ReagentManager : public QObject {
                            Q_OBJECT
                           private:
                            Bottles m_bottleList;
                          }
                          <in another file>
                            ReagentManager m_reagentManager;
                            engine->rootContext()->setContextProperty("reagentManager", &m_reagentManager);
                          

                          In QML:

                              onVisibleChanged: {
                                if (visible) {
                                  reagentManager.updateBottleList()
                                  rack.updateBottles()
                                }
                              }
                          
                              // update our QML array based on the C++ model.
                              function updateBottles() {
                                var modelSize = bottleModel.count
                                var i
                                var l_color
                                var volume
                                var minVolume
                                var amountNeeded
                                var name
                          
                                for (i = 0; i < modelSize; ++i) {
                                  name = reagentManager.getName(i)
                                  bottleRepeater.itemAt(i).cellText = name
                          
                                  volume = reagentManager.m_volume
                                  minVolume = reagentManager.getMinVolume(i)
                                  amountNeeded = reagentManager.getAmountNeeded(i)
                                  l_color = ((volume - minVolume) >= amountNeeded) ? "green" : "red"
                                  bottleRepeater.itemAt(i).cellColor = l_color
                                }
                              }
                          

                          So, my QML function calls C++ routines to obtain the needed data. I'm trying to convert this to the approach you suggested; this is where I ran into the problem with the struct.

                          I still don't see where the QVariantList comes into play, though.

                          ODБOïO Offline
                          ODБOïO Offline
                          ODБOï
                          wrote on last edited by ODБOï
                          #41

                          this is not directly related but
                          @mzimmers said in updating elements in a repeater?:

                          onVisibleChanged: {
                          if (visible) {
                          reagentManager.updateBottleList()
                          rack.updateBottles()
                          }
                          }

                          are you calling this in your Repeater delegate ? If yes, then i believe you will call this multiple times unnecessarily, one way to verify it in qml is putting a console.log() after or before this call to see how meny time this is called

                          1 Reply Last reply
                          1
                          • ODБOïO ODБOï

                            Q_INVOKABLE QVariant bottleList() { return QVariant::fromValue(m_bottleList); }

                            mzimmersM Offline
                            mzimmersM Offline
                            mzimmers
                            wrote on last edited by
                            #42

                            @LeLev said in updating elements in a repeater?:

                            Q_INVOKABLE QVariant bottleList() { return QVariant::fromValue(m_bottleList); }

                            Well, bless my buttons...that works! But why is bottleList() declared as returning a QVariant, and not a QVariantList?

                            Regarding your question: the onVisibleChanged isn't in the repeater; it's in the parent Rectangle. This was my way of ensuring that the C++ data in ReagentManager updates itself whenever the view is activated.

                            ODБOïO 1 Reply Last reply
                            1
                            • mzimmersM mzimmers

                              @LeLev said in updating elements in a repeater?:

                              Q_INVOKABLE QVariant bottleList() { return QVariant::fromValue(m_bottleList); }

                              Well, bless my buttons...that works! But why is bottleList() declared as returning a QVariant, and not a QVariantList?

                              Regarding your question: the onVisibleChanged isn't in the repeater; it's in the parent Rectangle. This was my way of ensuring that the C++ data in ReagentManager updates itself whenever the view is activated.

                              ODБOïO Offline
                              ODБOïO Offline
                              ODБOï
                              wrote on last edited by
                              #43

                              @mzimmers said in updating elements in a repeater?:

                              Well, bless my buttons...that works!

                              Nice :)

                              @mzimmers said in updating elements in a repeater?:

                              But why is bottleList() declared as returning a QVariant, and not a QVariantList?

                              I don't have a technical explanation for that really, im used to do that since i saw it somewhere in the docs. But i guess you could return a QVariantList directly. It will be converted to javascript array as explained here https://doc.qt.io/qt-5/qtqml-cppintegration-data.html

                              1 Reply Last reply
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