Color Editor Factory Example

Window Class Implementation

In the Window class, we create the item editor creator base for our color editor and add it to the default factory. We also create a QTableWidget in which our editor can be tested. It is filled with some data and displayed in a window.

We take a closer look at the constructor:

 Window::Window()
 {
     QItemEditorFactory *factory = new QItemEditorFactory;

     QItemEditorCreatorBase *colorListCreator =
         new QStandardItemEditorCreator<ColorListEditor>();

     factory->registerEditor(QVariant::Color, colorListCreator);

     QItemEditorFactory::setDefaultFactory(factory);

     createGUI();
 }

The QStandardItemEditorCreator is a convenience class that inherits QItemEditorCreatorBase. Its constructor takes a template class, of which instances are returned from createWidget(). The creator uses a constructor that takes a QWidget as its only parameter; the template class must provide this. This way, there is no need to subclass QStandardItemEditorCreator.

After the new factory has been set, all standard item delegates will use it (i.e, also delegates that were created before the new default factory was set).

The createGUI() function sets up the table and fills it with data.

 class ColorListEditor : public QComboBox
 {
     Q_OBJECT
     Q_PROPERTY(QColor color READ color WRITE setColor USER true)

 public:
     ColorListEditor(QWidget *widget = 0);

 public:
     QColor color() const;
     void setColor(QColor c);

 private:
     void populateList();
 };

 QColor ColorListEditor::color() const
 {
     return qVariantValue<QColor>(itemData(currentIndex(), Qt::DecorationRole));
 }

 void ColorListEditor::setColor(QColor color)
 {
     setCurrentIndex(findData(color, int(Qt::DecorationRole)));
 }

 void ColorListEditor::populateList()
 {
     QStringList colorNames = QColor::colorNames();

     for (int i = 0; i < colorNames.size(); ++i) {
         QColor color(colorNames[i]);

         insertItem(i, colorNames[i]);
         setItemData(i, color, Qt::DecorationRole);
     }
 }