Reflection on Qt

[tchoninho]

Hi everybody, I would use Reflection on Qt, but I do not know how I can do that. In Java, any object can be instantiated and be called even if unknown. In Qt, I can only do this when I know that this object. Has anyone used Reflection in Qt?

My Object:

class Obj : public QObject
{
    Q_OBJECT
 
public:
    Q_INVOKABLE Obj(QObject *parent = 0);
    Q_INVOKABLE virtual ~Obj();
 
    Q_INVOKABLE virtual QVariant execute (QList<QVariant> &);
    Q_INVOKABLE uint getKey();
};

class Obj : public QObject
{
    Q_OBJECT

public:
    Q_INVOKABLE Obj(QObject *parent = 0);
    Q_INVOKABLE virtual ~Obj();

    Q_INVOKABLE virtual QVariant execute (QList<QVariant> &);
    Q_INVOKABLE uint getKey();
};

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[squidge]

QMetaObject provides this functionality, you can use it to browse properties and methods of Qt Objects.

http://doc.qt.nokia.com/latest/qmetaobject.html

[scieck]

In Java, any object can be instantiated and be called even if unknown. In Qt, I can only do this when I know that this object

QMetaObject provides this functionality, you can use it to browse properties and methods of Qt Objects.

http://doc.qt.nokia.com/latest/qmetaobject.html

Does QMetaObject provide the functionality of creating and object?

If there is a class called MyClass that extends QObject, is it possible to instantiate it from a QString?
What I mean is, having a QString className("MyClass"); is it possible to instantiate an object of type MyClass?

If an object does not inherit from QObject, then via:

int type = qRegisterMetaType<AClass>();
and
Q_DECLARE_METATYPE(AClass);

int type = qRegisterMetaType<AClass>();
and
Q_DECLARE_METATYPE(AClass);

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Is possible to instantiate an object knowing its int type returned from qRegisterMetaType, but then is there a way to use introspection to query the object about its methods and parameters?

For example in Java is possible to do the following:

Class myclass = Class.forName("MyClass");
Method[] methods = myclass.getMethods();
for (int i = 0; i < methods.length; i++) 
{
    // methods can also be invoked
    System.out.println(methods[i].getName());
}

Class myclass = Class.forName("MyClass");
Method[] methods = myclass.getMethods();
for (int i = 0; i < methods.length; i++) 
{
    // methods can also be invoked
    System.out.println(methods[i].getName());
}

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Is it possible to do something similar using Qt?

---

Added after 45 minutes:

Ah found it, for anyone interested:

Having the following class:

class MyClass : public QObject
{
Q_OBJECT
public:
    Q_INVOKABLE MyClass(QObject *parent = 0);
 
public:
    Q_INVOKABLE void myMethod();
};

class MyClass : public QObject
{
Q_OBJECT
public:
    Q_INVOKABLE MyClass(QObject *parent = 0);

public:
    Q_INVOKABLE void myMethod();
};

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Then the following code will print the above class methods:

MyClass *obj = static_cast<MyClass*>(MyClass::staticMetaObject.newInstance());
for (int i = 0; i < obj->metaObject()->methodCount(); i++)
{
    QMetaMethod method = obj->metaObject()->method(i);
    qDebug() << method.signature();
}

MyClass *obj = static_cast<MyClass*>(MyClass::staticMetaObject.newInstance());
for (int i = 0; i < obj->metaObject()->methodCount(); i++)
{
    QMetaMethod method = obj->metaObject()->method(i);
    qDebug() << method.signature();
}

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the above will print something like:

destroyed(QObject*) 
destroyed() 
deleteLater() 
_q_reregisterTimers(void*) 
myMethod()

destroyed(QObject*) 
destroyed() 
deleteLater() 
_q_reregisterTimers(void*) 
myMethod()

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