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QSortFilterProxyModel, QAbstractItemModel

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  • S Slawomir_Piernikowski

    Which model are you talking about?:
    Castomized QAbstractTableModel

    For sorting in this case is responsible QSortFilterProxyModel::Sort function I only trigger this function by calling SetData function of The QAbstractTableModel or by clicking an arrow on header column of the TableView which is responsible for calling also QSortFilterProxyModel::Sort function

    So the order of the data in the Tableview is different than in the model(QAbstractTableModel).

    VRoninV Offline
    VRoninV Offline
    VRonin
    wrote on last edited by
    #4

    @Slawomir_Piernikowski said in QSortFilterProxyModel, QAbstractItemModel:

    So the order of the data in the Tableview is different than in the model

    Correct, that's what QSortFilterProxyModel does. It's 50% of its job (the remaining being the filtering part)

    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
    ~Napoleon Bonaparte

    On a crusade to banish setIndexWidget() from the holy land of Qt

    S 1 Reply Last reply
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    • VRoninV VRonin

      @Slawomir_Piernikowski said in QSortFilterProxyModel, QAbstractItemModel:

      So the order of the data in the Tableview is different than in the model

      Correct, that's what QSortFilterProxyModel does. It's 50% of its job (the remaining being the filtering part)

      S Offline
      S Offline
      Slawomir_Piernikowski
      wrote on last edited by
      #5

      @VRonin You said : Correct, that's what QSortFilterProxyModel does. It's 50% of its job (the remaining being the filtering part)
      If QSortFilterProxyModel::Sort function sorts data which I see in the TableView Why my
      model(customized QAbsrtractTableModel) data are not sorted????

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      • VRoninV Offline
        VRoninV Offline
        VRonin
        wrote on last edited by
        #6

        That's exactly what QSortFilterProxyModel model do. It reorders the indexes and maintain a mapping between its indexes and those of the source model.
        You can imagine it as a telephone switchboard but operating on the model indexes

        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
        ~Napoleon Bonaparte

        On a crusade to banish setIndexWidget() from the holy land of Qt

        S 1 Reply Last reply
        3
        • VRoninV VRonin

          That's exactly what QSortFilterProxyModel model do. It reorders the indexes and maintain a mapping between its indexes and those of the source model.
          You can imagine it as a telephone switchboard but operating on the model indexes

          S Offline
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          Slawomir_Piernikowski
          wrote on last edited by Slawomir_Piernikowski
          #7

          @VRonin ok but I need to have model data reorded the same way as the data are sorted and seen in the view

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          • VRoninV Offline
            VRoninV Offline
            VRonin
            wrote on last edited by VRonin
            #8

            Then you have to ditch the QSortFilterProxyModel and reimplement sort in your custom QAbstractItemModel emitting layoutAboutToBeChanged and layoutChanged and calling changePersistentIndexes

            "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
            ~Napoleon Bonaparte

            On a crusade to banish setIndexWidget() from the holy land of Qt

            S 1 Reply Last reply
            2
            • VRoninV VRonin

              Then you have to ditch the QSortFilterProxyModel and reimplement sort in your custom QAbstractItemModel emitting layoutAboutToBeChanged and layoutChanged and calling changePersistentIndexes

              S Offline
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              Slawomir_Piernikowski
              wrote on last edited by Slawomir_Piernikowski
              #9

              @VRonin I need QSortFilterProxyModel for I use it also for filtring data of the model.
              I also need to have consitency of the model(QAbstractTableModel) data and the data after sorting using QSortFilterProxyModel::Sort function.

              Maybe mapToSource and mapFormSource functions will be helpfull??????

              JonBJ 1 Reply Last reply
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              • S Slawomir_Piernikowski

                @VRonin I need QSortFilterProxyModel for I use it also for filtring data of the model.
                I also need to have consitency of the model(QAbstractTableModel) data and the data after sorting using QSortFilterProxyModel::Sort function.

                Maybe mapToSource and mapFormSource functions will be helpfull??????

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #10

                @Slawomir_Piernikowski
                For the record, we're not sure why you want the underlying data model to have the same sort order as the in the proxy model?

                Data doesn't really have a sort order, sorting is just one way of viewing the data. At different times you might sort by different criteria. The proxy model also provides filtering for the view, but you don't say you want rows omitted by the filter to be removed from the underlying model, which would be the equivalent change to what you are asking about sorting?

                S 1 Reply Last reply
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                • JonBJ JonB

                  @Slawomir_Piernikowski
                  For the record, we're not sure why you want the underlying data model to have the same sort order as the in the proxy model?

                  Data doesn't really have a sort order, sorting is just one way of viewing the data. At different times you might sort by different criteria. The proxy model also provides filtering for the view, but you don't say you want rows omitted by the filter to be removed from the underlying model, which would be the equivalent change to what you are asking about sorting?

                  S Offline
                  S Offline
                  Slawomir_Piernikowski
                  wrote on last edited by Slawomir_Piernikowski
                  #11

                  @JonB You wrote: we're not sure why you want the underlying data model to have the same sort order as the in the proxy model?
                  For during setting data(call SetData function of the customized QAbstractTableModel) or simpler saying clicking on a cell in the TableView and alter the data in it I take the:
                  int justRemovedRowIndex = cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex().row();
                  and everything is working perfectly if sorting is not involved.

                  VRoninV 1 Reply Last reply
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                  • S Slawomir_Piernikowski

                    @JonB You wrote: we're not sure why you want the underlying data model to have the same sort order as the in the proxy model?
                    For during setting data(call SetData function of the customized QAbstractTableModel) or simpler saying clicking on a cell in the TableView and alter the data in it I take the:
                    int justRemovedRowIndex = cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex().row();
                    and everything is working perfectly if sorting is not involved.

                    VRoninV Offline
                    VRoninV Offline
                    VRonin
                    wrote on last edited by
                    #12

                    @Slawomir_Piernikowski said in QSortFilterProxyModel, QAbstractItemModel:

                    int justRemovedRowIndex = cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex().row();

                    No idea what this means, you gave us 0 context to any of those symbols

                    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                    ~Napoleon Bonaparte

                    On a crusade to banish setIndexWidget() from the holy land of Qt

                    S 1 Reply Last reply
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                    • VRoninV VRonin

                      @Slawomir_Piernikowski said in QSortFilterProxyModel, QAbstractItemModel:

                      int justRemovedRowIndex = cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex().row();

                      No idea what this means, you gave us 0 context to any of those symbols

                      S Offline
                      S Offline
                      Slawomir_Piernikowski
                      wrote on last edited by
                      #13

                      @VRonin
                      int justRemovedRowIndex = cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex().row();

                      1. cMagazynView - pointer to class which have a member...
                        ... QVector<MagazynView *>vectMagazyn; - vector of MagazynView pointers
                        GetTabView() -
                      QTableView &MagazynView::GetTabView()
                      {
                         return *tabView;
                      }
                      

                      As it is simply to see I want to get row number of the currentIndex row of the TableView

                      JonBJ 1 Reply Last reply
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                      • S Slawomir_Piernikowski

                        @VRonin
                        int justRemovedRowIndex = cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex().row();

                        1. cMagazynView - pointer to class which have a member...
                          ... QVector<MagazynView *>vectMagazyn; - vector of MagazynView pointers
                          GetTabView() -
                        QTableView &MagazynView::GetTabView()
                        {
                           return *tabView;
                        }
                        

                        As it is simply to see I want to get row number of the currentIndex row of the TableView

                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by JonB
                        #14

                        @Slawomir_Piernikowski
                        As @VRonin has said, you have two approaches to sorting data from the model. Either you do not use a QSortFilterProxyModel and do the actual sorting yourself on the rows, or you do use it and the sorting happens in the proxy not the underlying data. Then, yes, you must "dereference" to get the actual index in the underlying data from the proxy, and for that you have https://doc.qt.io/qt-5/qsortfilterproxymodel.html#mapToSource. That's just how it is.

                        S 1 Reply Last reply
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                        • VRoninV Offline
                          VRoninV Offline
                          VRonin
                          wrote on last edited by VRonin
                          #15

                          QSortFilterProxyModel has a method to map back the index of the view to the original model: https://doc.qt.io/qt-5/qsortfilterproxymodel.html#mapToSource

                          Instead of using currentIndex().row() you can use proxyModel->mapToSource(currentIndex()).row()

                          "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                          ~Napoleon Bonaparte

                          On a crusade to banish setIndexWidget() from the holy land of Qt

                          S 1 Reply Last reply
                          2
                          • JonBJ JonB

                            @Slawomir_Piernikowski
                            As @VRonin has said, you have two approaches to sorting data from the model. Either you do not use a QSortFilterProxyModel and do the actual sorting yourself on the rows, or you do use it and the sorting happens in the proxy not the underlying data. Then, yes, you must "dereference" to get the actual index in the underlying data from the proxy, and for that you have https://doc.qt.io/qt-5/qsortfilterproxymodel.html#mapToSource. That's just how it is.

                            S Offline
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                            Slawomir_Piernikowski
                            wrote on last edited by
                            #16

                            @JonB ok thanks

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                            • VRoninV VRonin

                              QSortFilterProxyModel has a method to map back the index of the view to the original model: https://doc.qt.io/qt-5/qsortfilterproxymodel.html#mapToSource

                              Instead of using currentIndex().row() you can use proxyModel->mapToSource(currentIndex()).row()

                              S Offline
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                              Slawomir_Piernikowski
                              wrote on last edited by
                              #17

                              @VRonin ok I will try to use this

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                              • S Offline
                                S Offline
                                Slawomir_Piernikowski
                                wrote on last edited by
                                #18

                                After a fiew tests it looks like mapToSource did the trick.

                                auto magazynToBeRemoved = model->GetcMagazynVect().at(cFilterProxyModel->GetVectMagazynFilterProxyModel().at(index)->mapToSource(cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex()).row());
                                
                                JonBJ 1 Reply Last reply
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                                • S Slawomir_Piernikowski

                                  After a fiew tests it looks like mapToSource did the trick.

                                  auto magazynToBeRemoved = model->GetcMagazynVect().at(cFilterProxyModel->GetVectMagazynFilterProxyModel().at(index)->mapToSource(cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex()).row());
                                  
                                  JonBJ Offline
                                  JonBJ Offline
                                  JonB
                                  wrote on last edited by
                                  #19

                                  @Slawomir_Piernikowski
                                  Good. But do you really write that as a single line in your source code?

                                  S 1 Reply Last reply
                                  1
                                  • JonBJ JonB

                                    @Slawomir_Piernikowski
                                    Good. But do you really write that as a single line in your source code?

                                    S Offline
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                                    Slawomir_Piernikowski
                                    wrote on last edited by Slawomir_Piernikowski
                                    #20

                                    @JonB I know that it can be not so readable for everybody but since I have been working on my soft from allmost 8 monthes I am used to such long lines of code :-)). Usually I devided such a long lines of code like this:

                                    auto magazynToBeRemoved = model->GetcMagazynVect().at(cFilterProxyModel->GetVectMagazynFilterProxyModel().at(index)->
                                    
                                    mapToSource(cMagazynView->GetVectMagazyn().at(index)->GetTabView().currentIndex()).row());
                                    
                                    1 Reply Last reply
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