Yeah I get that, but I loose all the generic implementation from the interface
I could have done and I have to rewrite them. I did make some abstract methods
and header only template declaration that the abstract class can call, it's
just that I was looking at a way to have some concrete method along the
interface. That would save me many lines of useless code, the example with get
set are simple but I'm having methods that have to do a lot more.
But I guess it's the best we can do with abstract signals, is only to make them
exist but never call them until the class is abstract and a QObject. So at that
point the abstract signal is pretty much pointless since it serve no purpose,
you better check meta object and check for a signal name and signature to
call/connect it.
So it leave us with a few choices I see so far:
* inline template header function that will you do the function in all
abstract call
* create Macro that will generate the code into all the abstract class
I usually mix both to make this work and avoid code cluttering.
I wish I could create those easily and assemble my QObject by features
compositions (interfaces here that would have properties, methods, signals,
slots). Since we can only inherit a single QObject, making a composition is not
so easy, I feel I have to rewrite the same features over and over again to
different Object type just because they do not inherit the same base QObject
class but they just need the same features.
Thanks anyway,
Jerome
________________________________
From: Interest <interest-boun...@qt-project.org> on behalf of Stan Morris
<pixelgre...@gmail.com>
Sent: Monday, February 18, 2019 9:43 PM
To: interest@qt-project.org
Subject: Re: [Interest] [External] Interface with signals and slots (Jérôme
Godbout)
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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