Example of showing different context menu for items in a QTreeWidget (with QItemDelegate)

gistfile1.cpp

#include <QApplication>
#include <QItemDelegate>
#include <QMenu>
#include <QMouseEvent>
#include <QTreeWidget>
#include <QTreeWidgetItem>

// Qt documentation states that user types should begin at this value.
static const int ItemType1 = QTreeWidgetItem::UserType;
static const int ItemType2 = QTreeWidgetItem::UserType + 1;

class MyTreeWidget : public QTreeWidget
{
public:
    // Re-declare as public.
    QTreeWidgetItem* itemFromIndex(const QModelIndex& index) const;
};

class MyItemDelegate : public QItemDelegate
{
public:
    MyItemDelegate(MyTreeWidget* treeWidget) : _treeWidget(treeWidget)
    {
        // Do nothing.
    }

    // QAbstractItemDelegate override
    virtual bool editorEvent(
        QEvent* event,
        QAbstractItemModel* model,
        const QStyleOptionViewItem& option,
        const QModelIndex& index )
    {
        QMouseEvent* mouseEvent = NULL;

        if (event->type() == QEvent::MouseButtonPress) {
            // This is only safe because we've checked the type first.
            mouseEvent = static_cast<QMouseEvent*>(event);
        }

        if (mouseEvent and mouseEvent->button() == Qt::RightButton) {
            QTreeWidgetItem* item = _treeWidget->itemAt(mouseEvent->pos());

            showContextMenu(item, mouseEvent->globalPos());

            // Return true to indicate that we have handled the event.
            // Note: This means that we won't get any default behavior!
            return true;
        }

        return QAbstractItemDelegate::editorEvent(
            event, model, option, index);
    }

private:
    void showContextMenu(QTreeWidgetItem* item, const QPoint& globalPos) {
        QMenu menu;

        switch (item->type()) {
            case ItemType1:
                menu.addAction("This is a type 1");
                break;

            case ItemType2:
                menu.addAction("This is a type 2");
                break;
        }

        menu.exec(globalPos);
    }

private:
    MyTreeWidget* _treeWidget;
};

int main(int argc, char** argv)
{
    QApplication app(argc, argv);

    MyTreeWidget w;
    MyItemDelegate d(&w);

    w.setItemDelegate(&d);

    // Add test items.
    w.addTopLevelItem(new QTreeWidgetItem(QStringList("A (type 1)"),
                                          ItemType1));
    w.addTopLevelItem(new QTreeWidgetItem(QStringList("B (type 1)"),
                                          ItemType1));

    w.addTopLevelItem(new QTreeWidgetItem(QStringList("C (type 2)"),
                                          ItemType2));
    w.addTopLevelItem(new QTreeWidgetItem(QStringList("D (type 2)"),
                                          ItemType2));

    w.show();
    app.exec();
    return 0;
}