Qt动态重生类厂

class QConstructHelper

{

public:

    virtual void * create() = 0;

};

template<typename T>

class QMetaTypeConstructHelper : public QConstructHelper

{

public:

    QMetaTypeConstructHelper(){}

    void * create(){return new T;}

};

template<typename T>

int qRegisterConstructHelper(const char *name)

{

    return qRegisterMetaType< QMetaTypeConstructHelper<T> >(name);

}

void * qConstructHelper(const char* name);

QObject * qObjectConstructHelper( const char* name );

//关键函数的实现

void * qConstructHelper(const char* name)
{
    int id = QMetaType::type( name );
    if (id != QMetaType::UnknownType)
    {
        QConstructHelper * creator = static_cast<QConstructHelper*>(QMetaType::create( id ));
        if(creator)
        {
            void * p = creator->create();
            QMetaType::destroy(id,creator);
            return p;
        }
    }
    return NULL;
}

QObject * qObjectConstructHelper( const char* name )
{
    return  static_cast<QObject*>(qConstructHelper(name));
}

用法示例：

    qRegisterConstructHelper<Data>("myData");

    qRegisterConstructHelper<Widget>("widget");

    Widget * w = qobject_cast<Widget*>(qObjectConstructHelper("widget"));

    if(w)

    {

        w->show();

        return a.exec();

    }

另外这个函数可以创建Qt的原生对象（除窗体对象已外的）

void * qMetaTypeCreate(const char *name)

{

    int id = QMetaType::type( name );

    if (id != QMetaType::UnknownType)

    {

        return QMetaType::create( id );

    }

    return NULL;

}