Detailed Description

When you put a signal as a member of a class that derives from Qul::Object or Qul::Singleton, the qmlinterfacegenerator tool will generate a signal that can be connected from the QML code using the onXxxx:{...} syntax.

The template argument of the Signal shall be a function signature, including the parameters names which are used by qmlinterfacegenerator to expose them to qml.

Example:

class MySingleton : public Qul::Singleton<MySingleton> {
public:
    Qul::Signal<void()> changed; // signal without arguments
    Qul::Signal<void(int key, qreal value)> newValue; // signal with arguments
};

This can be used from QML like so:

MySingleton.onNewValue: console.log("Got a new value for key", key, ": ", value);

In order to emit the signal from the C++ code, you can use the operator().

MySingleton::instance().newValue(1, 3.141592);

If signal member is called exactly as the QML signal handler it will be treated as signal named without on prefix and starting with lower case letter.

Example:

class MyObject : public Qul::Object {
public:
    Qul::Signal<void()> onFoo; // signal named as QML signal handler
};

This can be used from QML like so:

Item {
    MyObject {
        id: myObject
        onFoo: console.log("Foo signal invoked.")
    }

    MouseArea: {
        onClicked: myObject.foo();
    }
}