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# variantdelegate.cpp Example File

tools/settingseditor/variantdelegate.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of The Qt Company Ltd nor the names of its
     **     contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
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     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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     #include <QtGui>

     #include "variantdelegate.h"

     VariantDelegate::VariantDelegate(QObject *parent)
         : QItemDelegate(parent)
     {
         boolExp.setPattern("true|false");
         boolExp.setCaseSensitivity(Qt::CaseInsensitive);

         byteArrayExp.setPattern("[\\x00-\\xff]*");
         charExp.setPattern(".");
         colorExp.setPattern("\\(([0-9]*),([0-9]*),([0-9]*),([0-9]*)\\)");
         doubleExp.setPattern("");
         pointExp.setPattern("\\((-?[0-9]*),(-?[0-9]*)\\)");
         rectExp.setPattern("\\((-?[0-9]*),(-?[0-9]*),(-?[0-9]*),(-?[0-9]*)\\)");
         signedIntegerExp.setPattern("-?[0-9]*");
         sizeExp = pointExp;
         unsignedIntegerExp.setPattern("[0-9]*");

         dateExp.setPattern("([0-9]{,4})-([0-9]{,2})-([0-9]{,2})");
         timeExp.setPattern("([0-9]{,2}):([0-9]{,2}):([0-9]{,2})");
         dateTimeExp.setPattern(dateExp.pattern() + "T" + timeExp.pattern());
     }

     void VariantDelegate::paint(QPainter *painter,
                                 const QStyleOptionViewItem &option,
                                 const QModelIndex &index) const
     {
         if (index.column() == 2) {
             QVariant value = index.model()->data(index, Qt::UserRole);
             if (!isSupportedType(value.type())) {
                 QStyleOptionViewItem myOption = option;
                 myOption.state &= ~QStyle::State_Enabled;
                 QItemDelegate::paint(painter, myOption, index);
                 return;
             }
         }

         QItemDelegate::paint(painter, option, index);
     }

     QWidget *VariantDelegate::createEditor(QWidget *parent,
             const QStyleOptionViewItem & /* option */,
             const QModelIndex &index) const
     {
         if (index.column() != 2)
             return 0;

         QVariant originalValue = index.model()->data(index, Qt::UserRole);
         if (!isSupportedType(originalValue.type()))
             return 0;

         QLineEdit *lineEdit = new QLineEdit(parent);
         lineEdit->setFrame(false);

         QRegExp regExp;

         switch (originalValue.type()) {
         case QVariant::Bool:
             regExp = boolExp;
             break;
         case QVariant::ByteArray:
             regExp = byteArrayExp;
             break;
         case QVariant::Char:
             regExp = charExp;
             break;
         case QVariant::Color:
             regExp = colorExp;
             break;
         case QVariant::Date:
             regExp = dateExp;
             break;
         case QVariant::DateTime:
             regExp = dateTimeExp;
             break;
         case QVariant::Double:
             regExp = doubleExp;
             break;
         case QVariant::Int:
         case QVariant::LongLong:
             regExp = signedIntegerExp;
             break;
         case QVariant::Point:
             regExp = pointExp;
             break;
         case QVariant::Rect:
             regExp = rectExp;
             break;
         case QVariant::Size:
             regExp = sizeExp;
             break;
         case QVariant::Time:
             regExp = timeExp;
             break;
         case QVariant::UInt:
         case QVariant::ULongLong:
             regExp = unsignedIntegerExp;
             break;
         default:
             ;
         }

         if (!regExp.isEmpty()) {
             QValidator *validator = new QRegExpValidator(regExp, lineEdit);
             lineEdit->setValidator(validator);
         }

         return lineEdit;
     }

     void VariantDelegate::setEditorData(QWidget *editor,
                                         const QModelIndex &index) const
     {
         QVariant value = index.model()->data(index, Qt::UserRole);
         if (QLineEdit *lineEdit = qobject_cast<QLineEdit *>(editor))
             lineEdit->setText(displayText(value));
     }

     void VariantDelegate::setModelData(QWidget *editor, QAbstractItemModel *model,
                                        const QModelIndex &index) const
     {
         QLineEdit *lineEdit = qobject_cast<QLineEdit *>(editor);
         if (!lineEdit->isModified())
             return;

         QString text = lineEdit->text();
         const QValidator *validator = lineEdit->validator();
         if (validator) {
             int pos;
             if (validator->validate(text, pos) != QValidator::Acceptable)
                 return;
         }

         QVariant originalValue = index.model()->data(index, Qt::UserRole);
         QVariant value;

         switch (originalValue.type()) {
         case QVariant::Char:
             value = text.at(0);
             break;
         case QVariant::Color:
             colorExp.exactMatch(text);
             value = QColor(qMin(colorExp.cap(1).toInt(), 255),
                            qMin(colorExp.cap(2).toInt(), 255),
                            qMin(colorExp.cap(3).toInt(), 255),
                            qMin(colorExp.cap(4).toInt(), 255));
             break;
         case QVariant::Date:
             {
                 QDate date = QDate::fromString(text, Qt::ISODate);
                 if (!date.isValid())
                     return;
                 value = date;
             }
             break;
         case QVariant::DateTime:
             {
                 QDateTime dateTime = QDateTime::fromString(text, Qt::ISODate);
                 if (!dateTime.isValid())
                     return;
                 value = dateTime;
             }
             break;
         case QVariant::Point:
             pointExp.exactMatch(text);
             value = QPoint(pointExp.cap(1).toInt(), pointExp.cap(2).toInt());
             break;
         case QVariant::Rect:
             rectExp.exactMatch(text);
             value = QRect(rectExp.cap(1).toInt(), rectExp.cap(2).toInt(),
                           rectExp.cap(3).toInt(), rectExp.cap(4).toInt());
             break;
         case QVariant::Size:
             sizeExp.exactMatch(text);
             value = QSize(sizeExp.cap(1).toInt(), sizeExp.cap(2).toInt());
             break;
         case QVariant::StringList:
             value = text.split(",");
             break;
         case QVariant::Time:
             {
                 QTime time = QTime::fromString(text, Qt::ISODate);
                 if (!time.isValid())
                     return;
                 value = time;
             }
             break;
         default:
             value = text;
             value.convert(originalValue.type());
         }

         model->setData(index, displayText(value), Qt::DisplayRole);
         model->setData(index, value, Qt::UserRole);
     }

     bool VariantDelegate::isSupportedType(QVariant::Type type)
     {
         switch (type) {
         case QVariant::Bool:
         case QVariant::ByteArray:
         case QVariant::Char:
         case QVariant::Color:
         case QVariant::Date:
         case QVariant::DateTime:
         case QVariant::Double:
         case QVariant::Int:
         case QVariant::LongLong:
         case QVariant::Point:
         case QVariant::Rect:
         case QVariant::Size:
         case QVariant::String:
         case QVariant::StringList:
         case QVariant::Time:
         case QVariant::UInt:
         case QVariant::ULongLong:
             return true;
         default:
             return false;
         }
     }

     QString VariantDelegate::displayText(const QVariant &value)
     {
         switch (value.type()) {
         case QVariant::Bool:
         case QVariant::ByteArray:
         case QVariant::Char:
         case QVariant::Double:
         case QVariant::Int:
         case QVariant::LongLong:
         case QVariant::String:
         case QVariant::UInt:
         case QVariant::ULongLong:
             return value.toString();
         case QVariant::Color:
             {
                 QColor color = qvariant_cast<QColor>(value);
                 return QString("(%1,%2,%3,%4)")
                        .arg(color.red()).arg(color.green())
                        .arg(color.blue()).arg(color.alpha());
             }
         case QVariant::Date:
             return value.toDate().toString(Qt::ISODate);
         case QVariant::DateTime:
             return value.toDateTime().toString(Qt::ISODate);
         case QVariant::Invalid:
             return "<Invalid>";
         case QVariant::Point:
             {
                 QPoint point = value.toPoint();
                 return QString("(%1,%2)").arg(point.x()).arg(point.y());
             }
         case QVariant::Rect:
             {
                 QRect rect = value.toRect();
                 return QString("(%1,%2,%3,%4)")
                        .arg(rect.x()).arg(rect.y())
                        .arg(rect.width()).arg(rect.height());
             }
         case QVariant::Size:
             {
                 QSize size = value.toSize();
                 return QString("(%1,%2)").arg(size.width()).arg(size.height());
             }
         case QVariant::StringList:
             return value.toStringList().join(",");
         case QVariant::Time:
             return value.toTime().toString(Qt::ISODate);
         default:
             break;
         }
         return QString("<%1>").arg(value.typeName());
     }