[Interest] [External] Interface with signals and slots (Jérôme Godbout)

[Stan Morris]

Re: [External]  Interface with signals and slots
      (Jérôme Godbout)

Your sample code declares an abstract IMyInterface rather than a class
interface; there are concrete method declarations. If you make them pure
virtual methods, your code compiles. You must implement the interface
functions in the subclass... that's just the way it is. You can inherit
multiple interfaces by implementing the getter/setters in the subclass.

Here are code changes that work:

class IMyInterface

{

public:

    explicit IMyInterface() {};

    virtual ~IMyInterface() {};


    virtual bool val() const = 0;

    virtual void setVal(const bool v) = 0;


signals:

    virtual void valChanged() const = 0;

};


class MyClass : public QObject, public IMyInterface

{

    Q_OBJECT

    Q_PROPERTY(bool val READ val WRITE setVal NOTIFY valChanged)

    Q_INTERFACES(IMyInterface)

public:

    MyClass() : m_val() {}

    bool val() const override { return m_val; }

    void setVal(const bool v) override

    {

        if (v != m_val) {

            m_val = v;

            emit valChanged();

        }

    }

signals:

    virtual void valChanged() const override;

private:

    bool m_val;

};


- Stan
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