How to set lower precision only for "view"

[lain]

Hi, thank you very much for reply.

I am using a custom delegate which uses QLineEdit as an editor.
I set the rounded data to the editor as below, but it does not seem to work.
The data are still shown as they are.
I may be misunderstanding the role of delegate...

LineEditDelegate::LineEditDelegate(QWidget *parent)
  : QStyledItemDelegate(parent), validator(new QDoubleValidator(this))
{
}
 
QWidget *LineEditDelegate::createEditor(QWidget *parent,
					const QStyleOptionViewItem &option,
					const QModelIndex &index) const
{
  QLineEdit *editor = new QLineEdit(parent);
  editor->setValidator(validator); 
  return editor;
}
 
void LineEditDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
  QLineEdit *e = qobject_cast<QLineEdit *>(editor);
  e->setText(QString::number(index.data(Qt::EditRole).toDouble(), 'f', 2));
}
 
void LineEditDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
				    const QModelIndex &index) const
{
  QLineEdit *e = qobject_cast<QLineEdit *>(editor);
  model->setData(index, e->text(), Qt::EditRole);
}

LineEditDelegate::LineEditDelegate(QWidget *parent)
  : QStyledItemDelegate(parent), validator(new QDoubleValidator(this))
{
}

QWidget *LineEditDelegate::createEditor(QWidget *parent,
					const QStyleOptionViewItem &option,
					const QModelIndex &index) const
{
  QLineEdit *editor = new QLineEdit(parent);
  editor->setValidator(validator); 
  return editor;
}

void LineEditDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
  QLineEdit *e = qobject_cast<QLineEdit *>(editor);
  e->setText(QString::number(index.data(Qt::EditRole).toDouble(), 'f', 2));
}
 
void LineEditDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
				    const QModelIndex &index) const
{
  QLineEdit *e = qobject_cast<QLineEdit *>(editor);
  model->setData(index, e->text(), Qt::EditRole);
}

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You could just use a custom delegate that would reduce precision for Qt:isplayRole.

But as far as DisplayRole and EditRole are not actually distinguished,
won't it overwrite the original with the rounded data?