Make some row/col can only accept hex-style input for QTableWidget ;

hex_item_delegate.hpp

#include <QLineEdit>
#include <QStyledItemDelegate>

/* 
// Sample
auto delegate = new HexItemDelegate;
ui->tableInfo->setItemDelegateForColumn(1, delegate);
ui->tableInfo->setItemDelegateForRow(1, delegate);
ui->tableInfo->setItemDelegate(delegate);
*/

class HexItemDelegate : public QStyledItemDelegate
{
public:
    QWidget* createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const override
    {
        QLineEdit* editor = new QLineEdit(parent);
        QRegExpValidator* validator = new QRegExpValidator(
                    QRegExp("[0-9A-Fa-f]+$"), editor);
        editor->setValidator(validator);
        return editor;
    }

    QString displayText(const QVariant& value, const QLocale& locale) const override
    {
        QString text = value.toString();

        text.remove('-');
        if (text.length() % 2 != 0)
        {
            text.prepend("0");
        }

        // Insert "-" separators every two characters
        int insertPos = 2;
        while (insertPos < text.length())
        {
            text.insert(insertPos, '-');
            insertPos += 3;
        }

        return text.toUpper();
    }

    void setEditorData(QWidget* editor, const QModelIndex& index) const override
    {
        QLineEdit* lineEdit = qobject_cast<QLineEdit*>(editor);
        if (lineEdit)
        {
            //QString text = lineEdit->displayText(); // now it's empty
            //QString text = lineEdit->text(); // now it's empty
            QString text = index.model()->data(index, Qt::EditRole).toString();
            lineEdit->setText(text);
        }
        else
        {
            QStyledItemDelegate::setEditorData(editor, index);
        }
    }

    void setModelData(QWidget* editor, QAbstractItemModel* model, const QModelIndex& index) const override
    {
        QLineEdit* lineEdit = qobject_cast<QLineEdit*>(editor);
        if (lineEdit)
        {
            QString text = lineEdit->text();
            text.remove('-');
            model->setData(index, text, Qt::EditRole);
        }
        else
        {
            QStyledItemDelegate::setModelData(editor, model, index);
        }
    }
};