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Use setData() from QML

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  • S sierdzio
    1 Apr 2020, 12:30

    ... and your problem is? Your code looks OK. If the delegate does not see the data (since it's in another file), you can try model.channel instead of channel.

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    ed_robcont_
    wrote on 1 Apr 2020, 12:51 last edited by ed_robcont_ 4 Jan 2020, 12:52
    #3

    @sierdzio
    First of all, thanks for your quick response.
    The problem is that I don't know how to use setData, index, or others model-related functions from QML. When I try console.log(model.channel) I alwasy get undefined.

    My final goal is to check/uncheck all the delegates' checkboxes when the header checkbox has been checked. My idea was somethig similar

    onHeaderPlotChecked: {
        console.log("check all " + checked);
       
        for (var i = 0; i < model.rowCounts(); < i++) {
            var index = model.index(i, 1); // get row
            model.setData(index, checked, model.PlottedRole); // replace data
        }
    }
    
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    • S Offline
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      sierdzio
      Moderators
      wrote on 1 Apr 2020, 13:02 last edited by
      #4

      The standard approach in QML is to not use data() and setData(). You should use model.roleName instead - bot for reading and writing.

      If you have to use setData(), this should work:

      modelId.setData(modelId.index(row, column), value, role)
      

      You need to create the index from the model. Using just integer won't work.

      (Z(:^

      E 1 Reply Last reply 1 Apr 2020, 13:27
      1
      • S sierdzio
        1 Apr 2020, 13:02

        The standard approach in QML is to not use data() and setData(). You should use model.roleName instead - bot for reading and writing.

        If you have to use setData(), this should work:

        modelId.setData(modelId.index(row, column), value, role)
        

        You need to create the index from the model. Using just integer won't work.

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        ed_robcont_
        wrote on 1 Apr 2020, 13:27 last edited by
        #5

        @sierdzio said in Use setData() from QML:

        The standard approach in QML is to not use data() and setData(). You should use model.roleName instead - bot for reading and writing.

        Ok, got it. But something is not working and I don't understand where and why.
        When I read data using model.plotted or similar, I always get undefined.
        Instead, when I try to replace some data, e.g. with model.plotted = true, the function setData() is never entered (I observed that on debug).

        If you have to use setData(), this should work:

        modelId.setData(modelId.index(row, column), value, role)
        

        You need to create the index from the model. Using just integer won't work.

        I've tried also this approach. In my previous response I used var index = model.index(i, 1) to iterate through indexes, but without success.

        May be a problem that my DataDelegate is in another QML file?

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          ed_robcont_
          wrote on 1 Apr 2020, 14:45 last edited by ed_robcont_ 4 Jan 2020, 14:49
          #6

          DONE!!
          I was picking an invalid index using 1 instead of 0 for column. Also the role values was wrong.
          Here below the "solution".

          // Read
          dmodel.data(dmodel.index(n, 0), DataModel.PlottedRole)
          
          // Write: 
          dmodel.setData(dmodel.index(n, 0), checked, DataModel.PlottedRole)
          

          Last question. By using index(row, column) is the only way to access to the n item of the list? Or I should implement my "custom getter" like this?

          DataItem DataModel::get(int row)
          {
              return mList.at(row);
          }
          
          S 1 Reply Last reply 2 Apr 2020, 04:38
          1
          • 6 Offline
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            6thC
            wrote on 2 Apr 2020, 04:11 last edited by
            #7
            This post is deleted!
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            • E ed_robcont_
              1 Apr 2020, 14:45

              DONE!!
              I was picking an invalid index using 1 instead of 0 for column. Also the role values was wrong.
              Here below the "solution".

              // Read
              dmodel.data(dmodel.index(n, 0), DataModel.PlottedRole)
              
              // Write: 
              dmodel.setData(dmodel.index(n, 0), checked, DataModel.PlottedRole)
              

              Last question. By using index(row, column) is the only way to access to the n item of the list? Or I should implement my "custom getter" like this?

              DataItem DataModel::get(int row)
              {
                  return mList.at(row);
              }
              
              S Offline
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              sierdzio
              Moderators
              wrote on 2 Apr 2020, 04:38 last edited by
              #8

              @ed_robcont_ said in Use setData() from QML:

              DONE!!
              I was picking an invalid index using 1 instead of 0 for column. Also the role values was wrong.

              Thanks for posting.

              DataItem DataModel::get(int row)
              {
                  return mList.at(row);
              }
              

              Since you're not using the standard approach anyway, I'd say it's up to you. A simple getter like this makes absolute sense.

              (Z(:^

              E 1 Reply Last reply 2 Apr 2020, 14:16
              0
              • S sierdzio
                2 Apr 2020, 04:38

                @ed_robcont_ said in Use setData() from QML:

                DONE!!
                I was picking an invalid index using 1 instead of 0 for column. Also the role values was wrong.

                Thanks for posting.

                DataItem DataModel::get(int row)
                {
                    return mList.at(row);
                }
                

                Since you're not using the standard approach anyway, I'd say it's up to you. A simple getter like this makes absolute sense.

                E Offline
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                ed_robcont_
                wrote on 2 Apr 2020, 14:16 last edited by
                #9

                @sierdzio

                It's working, so it's ok for me. Anyway, I'm still not understanding how the standard approach works.

                Task: Modify the temperature field in row 3 when a signal is emitted from another QML component.
                How to access this field in the standard way, without using setData()?

                S 1 Reply Last reply 2 Apr 2020, 16:01
                0
                • E ed_robcont_
                  2 Apr 2020, 14:16

                  @sierdzio

                  It's working, so it's ok for me. Anyway, I'm still not understanding how the standard approach works.

                  Task: Modify the temperature field in row 3 when a signal is emitted from another QML component.
                  How to access this field in the standard way, without using setData()?

                  S Offline
                  S Offline
                  sierdzio
                  Moderators
                  wrote on 2 Apr 2020, 16:01 last edited by
                  #10

                  @ed_robcont_ said in Use setData() from QML:

                  Task: Modify the temperature field in row 3 when a signal is emitted from another QML component.
                  How to access this field in the standard way, without using setData()?

                  Signal emitted from QML should go to your model. Then model should emit dataChanged() and this will update all affected delegates on QML side.

                  (Z(:^

                  E 1 Reply Last reply 3 Apr 2020, 09:30
                  1
                  • S sierdzio
                    2 Apr 2020, 16:01

                    @ed_robcont_ said in Use setData() from QML:

                    Task: Modify the temperature field in row 3 when a signal is emitted from another QML component.
                    How to access this field in the standard way, without using setData()?

                    Signal emitted from QML should go to your model. Then model should emit dataChanged() and this will update all affected delegates on QML side.

                    E Offline
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                    ed_robcont_
                    wrote on 3 Apr 2020, 09:30 last edited by ed_robcont_ 4 Mar 2020, 10:17
                    #11

                    @sierdzio said in Use setData() from QML:

                    Signal emitted from QML should go to your model. Then model should emit dataChanged() and this will update all affected delegates on QML side.

                    Ok, it works, thank you!

                    One more thing, it'll be the last I promise.
                    Actually, DataModel is the owner of my list. What I want is to add it from another class, i.e. DataServer. I tried this code but is not working. Any suggestion?

                    @DataServer.cpp

                    void DataServer::showList()
                    {
                        QVector<DataItem*> list;
                        list.append(new DataItem(...);
                        list.append(new DataItem(...);
                        list.append(new DataItem(...);
                    
                        emit listChanged(QVariant::fromValue(list));
                    }
                    

                    @DataModel

                    void DataModel::setList(QVariant list)
                    {
                        m_list = list;
                    }
                    

                    @QML

                    Button {
                        id: btn
                        onPressed: dserver.showList()
                    }
                    
                    DataServer {
                        id: dserver
                        onListChanged: dmodel.setList(list)
                    }
                    
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                    • S Offline
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                      sierdzio
                      Moderators
                      wrote on 3 Apr 2020, 09:46 last edited by
                      #12

                      void DataServer::setList(QVariant list)
                      {
                      m_list = list;
                      }

                      You don't have emit dataChanged() here. Or, in this case, you should probably do:

                      beginResetModel();
                      m_list = list;
                      endResetModel();
                      

                      (Z(:^

                      E 1 Reply Last reply 3 Apr 2020, 22:33
                      0
                      • S sierdzio
                        3 Apr 2020, 09:46

                        void DataServer::setList(QVariant list)
                        {
                        m_list = list;
                        }

                        You don't have emit dataChanged() here. Or, in this case, you should probably do:

                        beginResetModel();
                        m_list = list;
                        endResetModel();
                        
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                        ed_robcont_
                        wrote on 3 Apr 2020, 22:33 last edited by ed_robcont_ 4 Mar 2020, 22:54
                        #13

                        @sierdzio said in Use setData() from QML:

                        You don't have emit dataChanged() here. Or, in this case, you should probably do:

                        beginResetModel();
                        m_list = list;
                        endResetModel();
                        

                        Yes. No signal dataChanged() should be emitted.
                        I did the same you suggested, but I've getting this error.

                        qrc:/main.qml:21: Error: Unknown method parameter type: QVector<DataItem*>
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                          ed_robcont_
                          wrote on 3 Apr 2020, 23:02 last edited by
                          #14

                          Done, by inserting rows one by one.

                          1 Reply Last reply
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                          3 Apr 2020, 09:46

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