宏定义：

Q_GLOBAL_STATIC(NotifyManager,theInstance)

函数定义：

class NotifyManager  : public QObject
{
	Q_OBJECT

public:
	NotifyManager(QObject *parent = nullptr);
	~NotifyManager();

	static NotifyManager*getInstance();  //单例模式
}

源代码：

NotifyManager * NotifyManager::getInstance() {
	return theInstance();
}