Editable QComboBox with QItemDelegate

[Jmgr]

Hi all

I am trying to customize my QTreeView to get an editable QComboBox into a column.
There are some example on the Net, but I haven't seen any with an editable QComboBox, and mine does not work properly...

Let me explain : if I click into the cell and select an item from the list it works : the selection is saved. But if I enter free text and change the focus, then the text is lost, and my DisplayRole role contains nothing. But if I enter some text again, then it will be saved...

I searched without success some hours but didn't find any clue, so I'm posting here, maybe someone has a good idea about this...

Now, some code :

QWidget *ActionDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
	QComboBox *comboBox = new QComboBox(parent);
	comboBox->setEditable(true);
	comboBox->setInsertPolicy(QComboBox::NoInsert);
	comboBox->addItems(index.model()->data(index, CustomRoles::ValueRole).toStringList());
 
	connect(comboBox, SIGNAL(activated(int)), this, SLOT(emitCommitData()));
	connect(comboBox->lineEdit(), SIGNAL(editingFinished()), this, SLOT(emitCommitData()));
 
	QString currentText = index.model()->data(index, Qt::DisplayRole).toString();
	int selectedItem = comboBox->findText(currentText);
	if(selectedItem == -1)
		comboBox->setEditText(index.model()->data(index, Qt::DisplayRole).toString());
	else
		comboBox->setCurrentIndex(selectedItem);
 
	return comboBox;
}

QWidget *ActionDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
	QComboBox *comboBox = new QComboBox(parent);
	comboBox->setEditable(true);
	comboBox->setInsertPolicy(QComboBox::NoInsert);
	comboBox->addItems(index.model()->data(index, CustomRoles::ValueRole).toStringList());

	connect(comboBox, SIGNAL(activated(int)), this, SLOT(emitCommitData()));
	connect(comboBox->lineEdit(), SIGNAL(editingFinished()), this, SLOT(emitCommitData()));

	QString currentText = index.model()->data(index, Qt::DisplayRole).toString();
	int selectedItem = comboBox->findText(currentText);
	if(selectedItem == -1)
		comboBox->setEditText(index.model()->data(index, Qt::DisplayRole).toString());
	else
		comboBox->setCurrentIndex(selectedItem);

	return comboBox;
}

To copy to clipboard, switch view to plain text mode 

void ActionDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
	QComboBox *comboBox = qobject_cast<QComboBox*>(editor);
 
	comboBox->clear();
	comboBox->addItems(index.model()->data(index, CustomRoles::ValueRole).toStringList());
 
	QString currentText = index.model()->data(index, Qt::DisplayRole).toString();
	int selectedItem = comboBox->findText(currentText);
	if(selectedItem == -1)
		comboBox->setEditText(index.model()->data(index, Qt::DisplayRole).toString());
	else
		comboBox->setCurrentIndex(selectedItem);
}

void ActionDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
	QComboBox *comboBox = qobject_cast<QComboBox*>(editor);

	comboBox->clear();
	comboBox->addItems(index.model()->data(index, CustomRoles::ValueRole).toStringList());
	
	QString currentText = index.model()->data(index, Qt::DisplayRole).toString();
	int selectedItem = comboBox->findText(currentText);
	if(selectedItem == -1)
		comboBox->setEditText(index.model()->data(index, Qt::DisplayRole).toString());
	else
		comboBox->setCurrentIndex(selectedItem);
}

To copy to clipboard, switch view to plain text mode 

void ActionDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
	QComboBox* comboBox = qobject_cast<QComboBox*>(editor);
 
	QStringList value;
	for(int i=0;i<comboBox->count();++i)
		value.append(comboBox->itemText(i));
 
	int selectedItem = comboBox->findText(comboBox->currentText());
	if(selectedItem == -1)
	{
		model->setData(index, -1, CustomRoles::SelectedItemRole);
		model->setData(index, comboBox->currentText(), Qt::DisplayRole);
	}
	else
	{
		model->setData(index, selectedItem, CustomRoles::SelectedItemRole);
		model->setData(index, comboBox->itemText(selectedItem), Qt::DisplayRole);
	}
 
	model->setData(index, value, CustomRoles::ValueRole);
}

void ActionDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
	QComboBox* comboBox = qobject_cast<QComboBox*>(editor);

	QStringList value;
	for(int i=0;i<comboBox->count();++i)
		value.append(comboBox->itemText(i));

	int selectedItem = comboBox->findText(comboBox->currentText());
	if(selectedItem == -1)
	{
		model->setData(index, -1, CustomRoles::SelectedItemRole);
		model->setData(index, comboBox->currentText(), Qt::DisplayRole);
	}
	else
	{
		model->setData(index, selectedItem, CustomRoles::SelectedItemRole);
		model->setData(index, comboBox->itemText(selectedItem), Qt::DisplayRole);
	}

	model->setData(index, value, CustomRoles::ValueRole);
}

To copy to clipboard, switch view to plain text mode 

void ActionDelegate::emitCommitData()
{
	emit commitData(qobject_cast<QWidget *>(sender()));
}

void ActionDelegate::emitCommitData()
{
	emit commitData(qobject_cast<QWidget *>(sender()));
}

To copy to clipboard, switch view to plain text mode 

CustomRoles::SelectedItemRole represents the currently selected item, or -1 if it's free text
CustomRoles::ValueRole represents all the items of the combo box