1.一定要将public QObject放在public QGraphicsItem的前面,并且在该类的定义中添加Q_OBJECT宏.
class XXGraphicsItem : public QObject, public QGraphicsItem
编译时出现警告 Warning: Class Node implements the interface QGraphicsItem but does not list it in Q_INTERFACES. qobject_cast to QGraphicsItem will not work!
在类的声明(Q_OBJECT下面)中添加:Q_INTERFACES(QGraphicsItem)可解决该问题.
class XXGraphicsItem : public QObject, public QGraphicsItem
{
Q_OBJECT
Q_INTERFACES(QGraphicsItem)