error: C2039: “staticMetaObject”: 不是“QgsAnnotationMarkerItem”的成员

#include <QObject>
class mySvgItem:public QObject,QgsAnnotationMarkerItem//QObject一定要写前面
{
    Q_OBJECT//加上这个宏
public:
    mySvgItem(const QgsPoint &point);
    QgsRectangle 	boundingBox () const override;

};