Calling c++ method from QML.

Ahti

Hi
I am trying to call a c++ method from a qml but I am not able to do so because of the error: undefined reference to 'vtable for Example'.

My Code:

example.h

class Example: public QObject
{
    Q_OBJECT
    public:

        explicit Example(QObject *parent = 0);      
        Q_INVOKABLE bool example_method(int );
}

example.cpp

Example::Example(QObject *parent) : QObject(parent) {}
bool Example::example_method() { ... }

main.cpp

int main() {
    ...
    Example adjust;
    engine.rootContext()->setContextProperty("example", &example);
    ...
}

main.qml

Slider {
       ...
       onValueChanged: {
             example.example_method(value)
      }
}

Please help how to fix this problem ?

Nifiro

class Example : public QObject
{
    Q_OBJECT
    public:
        explicit Example(QObject *parent = 0);      
        Q_INVOKABLE bool example_method(int );
        virtual ~Example() override {}
}

Ahti

@Nifiro Still the same error.

KroMignon

@Ahti Do you have tried to call qmake and rebuild the project?

Ahti

@KroMignon How to do it ? both ? I am a newbie to qt

mrjj

@Ahti
alt text

or to really clean it,
alt text
and delete the build folder

Ahti

@mrjj Thanks I simple deleted the built and hit re-built and it worked thanks again :)