Remove CellWidget from QTableWidget when focus out - qt

Question

I have a QTableWidget in which some cells have QComboBox as cellWidget. I want to create the comboBox only when the user clicks in the cell. For this, I have caught itemClicked signal and created the comboBox and set it as cellWidget.
Now, I want to delete this comboBox in two scenarios - if the user selects some value from the comboBox, or the user simply focusses out (click anywhere in the dialog).
For the first case, I have use the signal QComboBox::activated which is invoked when something is selected in the drop-down. There I delete the comboBox and it works fine.
However, I am not sure how to proceed for the second case (delete the comboBox when the user focusses out of the drop-down without selecting anything).
I tried capturing eventFilter for focusOut for the tablewidget as well as the comboBox, but it didn't help.

Answer 1

You can use QItemDelegate for this purpose:
comboboxdelegate.h
class ComboBoxDelegate : public QItemDelegate
{
Q_OBJECT
public:
ComboBoxDelegate(QObject *parent = nullptr) :
QItemDelegate(parent)
{
}
QWidget* createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QComboBox *editor = new QComboBox(parent);
editor->addItems(QStringList() << "1" << "2" << "3" << "4"); // fill it with your own values
return editor;
}
void setEditorData(QWidget *editor, const QModelIndex &index) const
{
QString text = index.model()->data(index, Qt::EditRole).toString();
QComboBox *cb = static_cast<QComboBox*>(editor);
cb->setCurrentText(text);
}
void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
QComboBox *cb = static_cast<QComboBox*>(editor);
QString text = cb->currentText();
model->setData(index, text, Qt::EditRole);
}
void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
editor->setGeometry(option.rect);
}
};
mainwindow.cpp
...
ui->tableWidget->setItemDelegate(new ComboBoxDelegate);
...