[Interest] How to create QObject-derived class instance from class name

[André Somers]

Op 02/03/2016 om 11:51 schreef Sina Dogru:
>
>     >For now there is a design choice which I feel weak myself, to do
>     factory or to use QMetaType for creating instances.
>
>     Depends on the use case I suppose. If you know the types at
>     compile time, as is usually the case I'd go with the simple
>     solution to make a factory. I recently, however, had a case where
>     the deserialization routine couldn't know at compile time the
>     exact type (i.e. for a library), so I had to put a (gadget) base
>     class and use the runtime type ids.
>
>
> Since I'm trying to recover states of the QObject-derived class 
> instances from a file, it is not possible to know the types at compile 
> time. But is not that factory was also for creating objects that type 
> is known at run-time? Or am I missing something? Because I thought 
> both factory and metaobject system provide run-time object creation?
You are right. If you know the type you need at compile time, just 
construct the instance directly.
Factories are useful for the creation of objects who's types you do 
_not_ know at compile time. And indeed, as demonstrated above, the 
metaobject system together with the metatype system can also be abused 
to do the same thing.

André

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