QListView items also showing the delegate editor even though the delegate is only added to the QTableView

Question

I have a QListView and a QTableView both have the same QStandardItemModel. I have added a custom delegator to the QTableView. Now when I go to my QTableView and double-click an item I see the delegate editor widget, now if I go to my QListView and double-click the same item I see the delegate editor widget there as well. Point to be noted is that I see the editor widget only for those items in QListView which have been double-clicked in QTableView already. Whats going on here? Why do QListView items also showing the delegate editor widget even though the delegate is only added to the QTableView?

For reference, I am having below code:

#include <QtWidgets/QApplication>
#include <QtGui>
#include <QCombobox>
#include <QListview>
#include <QTableview>
#include <QLayout>
#include <QColor>
#include <QStyledItemDelegate>
#include <QSpinbox>

class SpinBoxDeligate : public QStyledItemDelegate {
public:
    QWidget * createEditor(QWidget *parent,
        const QStyleOptionViewItem &option,
        const QModelIndex &index) const override {
        auto w = new QSpinBox(parent);
        w->setFrame(false);
        w->setMinimum(0);
        w->setMaximum(100);
        return w;
    }

    void setEditorData(QWidget *editor, const QModelIndex &index) const override {
        static_cast<QSpinBox*>(editor)->setValue(index.data(Qt::EditRole).toInt());
    }

    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override {
        model->setData(index, static_cast<QSpinBox*>(editor)->value(), Qt::EditRole);
    }
};


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

    QStandardItemModel model(3, 1);

    for (int r = 0; r < 3; ++r)
    {
        auto text = QString("%0").arg(r);
        QStandardItem* item = new QStandardItem(text);

        item->setFlags(Qt::ItemIsUserCheckable
            | Qt::ItemIsEnabled
            | Qt::ItemIsEditable
        );
        item->setData(Qt::Unchecked, Qt::CheckStateRole);
        item->setData(text, Qt::ToolTipRole);
        item->setData(QSize(100, 30), Qt::SizeHintRole);
        item->setData(QIcon(":/QtMVC/Desert.jpg"), Qt::DecorationRole);
        model.setItem(r, 0, item);
    }

    QComboBox* combo = new QComboBox();
    combo->setModel(&model);

    QListView* list = new QListView();
    list->setModel(&model);

    QTableView* table = new QTableView();
    table->setModel(&model);
    table->setItemDelegate(new SpinBoxDeligate());

    QWidget w;
    QVBoxLayout* containerLayout = new QVBoxLayout();
    w.setLayout(containerLayout);
    containerLayout->addWidget(combo);
    containerLayout->addWidget(list);
    containerLayout->addWidget(table);
    w.show();

    return app.exec();
}

Answer 1

The problem is really simple, if the data saved in the model are numbers the delegate is a QSpinBox by default, ie the delegate you see is the QListView is not the SpinBoxDeligate, but the delegate by default.

And why is it generated if you do not keep a number? It's because the SpinBoxDeligate saves the data as a number.

So the solution is to save the data obtained by the SpinBoxDeligate as text:

void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const override {
    model->setData(index, static_cast<QSpinBox*>(editor)->text(), Qt::EditRole);
}