QJSEngine: Q_INVOKABLE method that returns pointer to subclass of QObject

dimonomid

Suppose I have some class that derives from QObject:

class MyTest : public QObject {
Q_OBJECT
   // ... 
};

And I want to return pointer to this class from some Q_INVOKABLE method, like this:

   Q_INVOKABLE MyTest *createMyTest(){
      return new MyTest();
   }

However, when I try to invoke this method from the script in QJSEngine, I get the following error:

Error: Unknown method return type: MyTest*

If I make createMyTest() to return QObject* instead of MyTest*, it works. But of course this would force me to use casts, which I'd like to avoid. So, how to make it work with MyTest*?
Just by chance, I tried to declare metatype, as follows:

Q_DECLARE_METATYPE(MyTest*)

But this didn't help.
Thanks in advance.

Leonardo

You need to register your subclass to have it available in qml.

qmlRegisterType<MyTest>();

dimonomid

@Leonardo, thank you, that works.

I'm still confused by the QML and QJSEngine interrelation. Like, how large part of QML should I learn in order just to use QJSEngine.

And, for example, how to use qml's import in JavaScript (not QML) code? Say, if I register instantiable type like this:

qmlRegisterType<MyTest>("com.mycompany.myclasses", 1, 0, "MyTest");

Does that mean that I should import com.mycompany.myclasses somehow, in order for things to work correctly? QJSEngine documentation doesn't contain things related to this.

Leonardo

Hi. I'm not sure I understand what you mean, but take a look here:

http://doc.qt.io/qt-5/qtqml-javascript-imports.html#imports-within-javascript-resources

It might help.