Flat leaf Proxy



  • I have a model (QStandardItemModel actually) with a list of data (10 columns) each row data contains the sum off all children items. so it's a very basic tree with just one level. now I'd like to display all child items of all the tree nodes in a flat table. To achieve it I thought about a ProxyModel. Here is what I did:

    #ifndef CHILDTABLEPROXY_H
    #define CHILDTABLEPROXY_H
    
    #include <QAbstractProxyModel>
    
    class ChildTableProxy : public QAbstractProxyModel
    {
       Q_OBJECT
    
    public:
       ChildTableProxy(QObject *parent);
       virtual QModelIndex mapToSource(const QModelIndex& proxyIndex) const override;
       virtual QModelIndex mapFromSource(const QModelIndex& sourceIndex) const override;
       virtual int rowCount(const QModelIndex& parent = QModelIndex()) const override;
       virtual int columnCount(const QModelIndex& parent = QModelIndex()) const override;
       virtual bool insertColumns(int column, int count, const QModelIndex& parent = QModelIndex())override;
       virtual bool insertRows(int row, int count, const QModelIndex& parent = QModelIndex())override;
       virtual bool removeColumns(int column, int count, const QModelIndex& parent = QModelIndex())override;
       virtual bool removeRows(int row, int count, const QModelIndex& parent = QModelIndex())override;
       virtual QItemSelection mapSelectionToSource(const QItemSelection& selection) const override;
       virtual QItemSelection mapSelectionFromSource(const QItemSelection& selection) const override;
       virtual QModelIndex parent(const QModelIndex& child) const override;
       virtual QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override;
       virtual QVariant data(const QModelIndex & proxyIndex, int role = Qt::DisplayRole) const override;
    protected:
       virtual QModelIndex getSourceIndex(int row, int column) const;
    };
    
    #endif // CHILDTABLEPROXY_H
    
    #include "ChildTableProxy.h"
    #include <QItemSelection>
    ChildTableProxy::ChildTableProxy(QObject *parent)
        : QAbstractProxyModel(parent)
    {}
    
    
    
    QModelIndex ChildTableProxy::mapFromSource(const QModelIndex& sourceIndex) const
    {
        if (!sourceIndex.isValid())
            return QModelIndex();
        if (!sourceIndex.parent().isValid())
            return QModelIndex();
        int row = sourceIndex.row();
        for (int i = 0; i < sourceIndex.parent().row(); ++i)
            row += sourceIndex.model()->rowCount(sourceIndex.model()->index(i, 0));
        return index(row, sourceIndex.column());
    }
    
    int ChildTableProxy::rowCount(const QModelIndex& parent) const
    {
        if (parent.isValid())
            return 0;
        int result = 0;
        for (int i = 0; i < sourceModel()->rowCount();++i){
            result += sourceModel()->rowCount(sourceModel()->index(i, 0));
        }
        return result;
    }
    
    int ChildTableProxy::columnCount(const QModelIndex& parent) const
    {
        if (parent.isValid())
            return 0;
        return sourceModel()->columnCount();
    }
    
    bool ChildTableProxy::insertColumns(int, int, const QModelIndex&)
    {
        return false;
    }
    
    bool ChildTableProxy::insertRows(int , int , const QModelIndex&)
    {
        return false;
    }
    
    bool ChildTableProxy::removeColumns(int , int , const QModelIndex& )
    {
        return false;
    }
    
    bool ChildTableProxy::removeRows(int , int , const QModelIndex&  )
    {
        return false;
    }
    
    QItemSelection ChildTableProxy::mapSelectionToSource(const QItemSelection& selection) const
    {
        QItemSelection result;
        const QModelIndexList allSelected = selection.indexes();
        for (auto i = allSelected.constBegin(); i != allSelected.constEnd(); ++i) {
            const QModelIndex mapped = mapToSource(*i);
            result.select(mapped, mapped);
        }
        return result;
    }
    
    QItemSelection ChildTableProxy::mapSelectionFromSource(const QItemSelection& selection) const
    {
        QItemSelection result;
        const QModelIndexList allSelected = selection.indexes();
        for (auto i = allSelected.constBegin(); i != allSelected.constEnd(); ++i) {
            const QModelIndex mapped = mapFromSource(*i);
            result.select(mapped, mapped);
        }
        return result;
    }
    
    QModelIndex ChildTableProxy::parent(const QModelIndex&) const
    {
        return QModelIndex();
    }
    
    QModelIndex ChildTableProxy::index(int row, int column, const QModelIndex &parent) const
    {
        if (parent.isValid())
            return QModelIndex();
        QModelIndex sourceIdx = getSourceIndex(row,column);
        if(!sourceIdx.isValid())
            return QModelIndex();
        return createIndex(row, column, sourceIdx.internalPointer());
    }
    
    QVariant ChildTableProxy::data(const QModelIndex & proxyIndex, int role) const
    {
        return sourceModel()->data(mapToSource(proxyIndex),role);
    }
    
    QModelIndex ChildTableProxy::getSourceIndex(int row, int column) const
    {
        if (row < 0 || column < 0 || column >= columnCount())
            return QModelIndex();
        for (int i = 0; i < sourceModel()->rowCount(); ++i) {
            if (row >= sourceModel()->rowCount(sourceModel()->index(i, 0)))
                row -= sourceModel()->rowCount(sourceModel()->index(i, 0));
            else
                return sourceModel()->index(row, column, sourceModel()->index(i, 0));
        }
        // row>rowCount()
        return QModelIndex();
        
    }
    QModelIndex ChildTableProxy::mapToSource(const QModelIndex& proxyIndex) const
    {
        if (!proxyIndex.isValid())
            return QModelIndex();
        if (proxyIndex.parent().isValid())
            return QModelIndex();
        return getSourceIndex(proxyIndex.row(), proxyIndex.column());
    }
    

    Unfortunately, despite rowcount returning the correct number, data is never called with a row greater than 0. What am I doing wrong?
    Thanks in advance



  • How are you viewing the model?


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