[Qt-interest] How to create object instance knowing only its class name in a QString?

[frares at gmail.com]

On , Mandeep Sandhu <mandeepsandhu.chd at gmail.com> wrote:
> On Mon, Jan 30, 2012 at 6:27 PM, frares at gmail.com> wrote:
> > Hi, all.
> >
> > How do I instantiate an object knowing its class name in a QString and  
> that
> > all similar classes are derived from a "facade" super class?
> >

> You can use the factory pattern here. The QMetaObject class is your
> friend in such cases.
> Eg: You can keep a map of class names to their corresponding static
> meta-objects and then invoke QMetaObject::newInstance() to create an
> object of that class.

> Here's some sample code:

> class ObjectFactory
> {
> public:
> template
> void registerClass(const QString &className)
> {
> m_factoryObjects.insert(className, &(T::staticMetaObject));
> }

> template
> T* createObject(const QString &className, QObject *parent = 0)
> {
> const QMetaObject *meta = m_factoryObjects.value(className);

> return (meta ?
> qobject_cast(meta->newInstance(Q_ARG(QObject *, parent)))
> : 0);
> }

> private:
> QHash m_factoryObjects;
> };

> HTH,
> -mandeep


Thank you.

Thanks for the QHash idea, also.

Francisco
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