HowTo combine QAbstractTableModel and QItemDelegate to one working source?

Question

I have a QTableView defines in UI file. Here is the figure:

I'd like to make month change (where the red array points) with QComboBox widget, dealing with delegates, but for me, for my custom delegate and model it's a too complex problem, and I can't figure out what is wrong?!

Problem: on my opinion, QAbstractTableModel can't work with QItemDelegate, because I'm unable to combine my custom simple ComboBoxDelegate widget with QTableView. Wtf?

Here is what I have:

My custom delegate header/source data:

class ComboBoxDelegate : public QItemDelegate
{
    Q_OBJECT

public:
    ComboBoxDelegate(QObject *parent = 0);

    QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option,
        const QModelIndex &index) const;

    void setEditorData(QWidget *editor, const QModelIndex &index) const;
    void setModelData(QWidget *editor, QAbstractItemModel *model,
                        const QModelIndex &index) const;

    void updateEditorGeometry(QWidget *editor,
        const QStyleOptionViewItem &option, const QModelIndex &index) const;
};

ComboBoxDelegate::ComboBoxDelegate(QObject *parent)
    : QItemDelegate(parent)
{}

QWidget *ComboBoxDelegate::createEditor(QWidget *parent,
    const QStyleOptionViewItem &/* option */,
    const QModelIndex &index) const
{
    QComboBox* editor = new QComboBox(parent);
    editor->addItem(index.data(Qt::DisplayRole).toString());
    return editor;
}

void ComboBoxDelegate::setEditorData(QWidget *editor,
    const QModelIndex &index) const
{
    QString value = index.model()->data(index, Qt::EditRole).toString();
    QComboBox *comboBox = static_cast<QComboBox*>(editor);
    comboBox->setCurrentIndex(comboBox->findText(value));
}

void ComboBoxDelegate::setModelData(QWidget *editor,
    QAbstractItemModel *model,
    const QModelIndex &index) const
{
    QComboBox *comboBox = static_cast<QComboBox*>(editor);
    QString value = comboBox->currentText();
    model->setData(index, value, Qt::EditRole);
}

Model data:

class PortfolioModel : public QAbstractTableModel
{
    Q_OBJECT;

    // types
    enum Position
    {
          ePosValue = 0
        , eColumnCount
    };

    enum Constants
    {
          eLocalCcy = 0
            , eCurrentTime
        , eCurrentMonthName
        , eRowCount
    };

    // data
    static QFont    font_;
    static QBrush   foreground_;
    static QBrush   background_;

    // methods
    QVariant        _valueName(int index) const;
    QVariant        _valueNameTooltip(int index) const;
    QVariant        _data(int index, int col, bool tooltip) const;

public:
    PortfolioModel(QObject* parent = 0);
    ~PortfolioModel();

    int         rowCount(const QModelIndex& parent = QModelIndex()) const;
    int         columnCount(const QModelIndex& parent = QModelIndex()) const;

    QVariant        data(const QModelIndex& index, int role = Qt::DisplayRole) const;
    QVariant        headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const;

signals:
    void            resizeToContents(void);

public slots:
    void            refreshData(void);
};

QFont PortfolioModel::font_ = QFont("Tahoma", 8, QFont::Normal);
QBrush PortfolioModel::foreground_ = QBrush(QColor("#000000")); // Black
QBrush PortfolioModel::background_ = QBrush(QColor("#C3FDB8")); // Dark Sea Green1

PortfolioModel::PortfolioModel(QObject* parent)
    : QAbstractTableModel(parent)
{}

PortfolioModel::~PortfolioModel()
{}

void PortfolioModel::refreshData(void)
{
    emit dataChanged(QModelIndex(), QModelIndex());
    emit resizeToContents();
}

int PortfolioModel::rowCount(const QModelIndex& parent/* = QModelIndex()*/) const
{
    return eRowCount;
}

int PortfolioModel::columnCount(const QModelIndex& parent/* = QModelIndex()*/) const
{
    return eColumnCount;
}

QVariant PortfolioModel::data(const QModelIndex& index, int role/* = Qt::DisplayRole*/) const
{
    if (!index.isValid())
        return QVariant();

    switch (role)
    {
        case Qt::DisplayRole:
            return _data(index.row(), index.column(), false);
        case Qt::FontRole:
            break;
        case Qt::BackgroundRole:
            return background_;
        case Qt::ForegroundRole:
            return foreground_;
        case Qt::TextAlignmentRole:
        case Qt::DecorationRole:
        case Qt::EditRole:
            break;
        case Qt::ToolTipRole:
            return _data(index.row(), index.column(), true);
        case Qt::StatusTipRole:
        case Qt::WhatsThisRole:
        case Qt::SizeHintRole:
            break;
    }
    return QVariant();
}

QVariant PortfolioModel::headerData(int section, Qt::Orientation orientation, int role) const
{
    switch (orientation)
    {
    case Qt::Horizontal:
        switch (role)
        {
        case Qt::DisplayRole:
            if (section == ePosValue)
            {
                return QVariant("Value");
            }
        case Qt::ToolTipRole:
            if (section == ePosValue)
            {
                return QVariant("Fund values");
            }
            break;
        }
    case Qt::Vertical:
        switch (role)
        {
        case Qt::DisplayRole:
            return _valueName(section);
        case Qt::ToolTipRole:
            return _valueNameTooltip(section);
        }
        break;
    }

    return QVariant();
}

QVariant PortfolioModel::_valueNameTooltip(int index) const
{
    switch (index)
    {
    case eLocalCcy:
        return QObject::tr("Local currency");
    case eCurrentTime:
        return QObject::tr("Current time");
    case eCurrentMonthName:
        return QObject::tr("Current Month");
    }
    return QVariant();
}

QVariant PortfolioModel::_valueName(int index) const
{
    switch (index)
    {
    case eLocalCcy:
        return QObject::tr("Local Currency");
    case eCurrentTime:
        return QObject::tr("Current Time");
    case eCurrentMonthName:
        return QObject::tr("Month");
    }
    return QVariant();
}

QVariant PortfolioModel::_data(int index, int col, bool tooltip) const
{
    switch (index)
    {
    case eLocalCcy:
        if (col == ePosValue)
        {
            return QString(Nav::bk()->currentFund().currency(Nav::bk()->currentFund().localCcy()).code());
        }
        break;
    case eCurrentTime:
        if (col == ePosValue)
        {
            return Nav::bk()->currentFund().currentTime();
        }
        break;
    case eCurrentMonthName:
        if (col == ePosValue)
        {
            return QDate::longMonthName(Nav::bk()->currentFund().currentTime().date().month());
        }
        break;
    }
    return QVariant();
}

And after that I made init delegate like that:

ComboBoxDelegate *delegate_ = new ComboBoxDelegate(this);
this->ui.tableView->setItemDelegate(delegate_);

PS: sorry for the long output, but I think it's will be better If all sources will be presented here.

Thanks!

---

1. Added:
   • Links:
     • http://qtwiki.org/Category:QT_Widgets_components
     • http://www.sfr-fresh.com/unix/privat/gle-graphics-4.2.2f-src.tar.gz:a/gle-graphics-4.2.2/src/gui/variantdelegate.cpp

Answer 1

From the overview of QAbstractItemModel (see the Subclassing heading):

To enable editing in your model, you must also implement setData(), and reimplement flags() to ensure that ItemIsEditable is returned.

The same information is given in the overview of QAbstractTableModel. Your PortfolioModel class does not reimplement either of these functions. In order to use the delegate's editor, you need to use do so.

Alternately, you may only want it to appear as if a combobox is there (not actually allow editing). If that is the case, you will probably need to do some drawing hacks yourself to make it appear that way... or mark it as editable but disable the widget, or something like that.

Answer 2

in this blog http://qt-articles.blogspot.com/2010/07/how-to-customize-listview-in-qt-using.html one delegate example is given.. please check your delegate with the sample example of the delegate present in blog. hope you might get some clue.