We can also use various other property types. QML has built-in support for the types listed in the QML Basic Types documentation, which includes the following:
- bool, unsigned int, int, float, double, qreal
- QString, QUrl, QColor
- QDate, QTime, QDateTime
- QPoint, QPointF, QSize, QSizeF, QRect, QRectF
- QVariant
If we want to create a property whose type is not supported by QML by default, we need to register the type with QML.
要点：
改为PieSlice 画图，PieChart不可视。
Like PieChart, this new PieSlice type inherits from QDeclarativeItem and declares its properties with Q_PROPERTY():
Q_PROPERTY(PieSlice* pieSlice READ pieSlice WRITE setPieSlice)
//![0]
void PieChart::setPieSlice(PieSlice *pieSlice)
{
m_pieSlice = pieSlice;
pieSlice->setParentItem(this);
}
//![0]