How connect a signal from C++ to QML function with parameter

Question

I want to connect a signal which is created by a C++ QObject to a function in a QML item. The signal is the "activated" signal from a QSystemTrayIcon and its argument is ActivationReason (an enum value).

Unfortunately it seems I can't connect a signal with this signature to a slot which seems to only be able to receive QVariant.

In the QML file

function trayIconClicked(reason) { ... }

In the C++ code

QObject::connect(trayIcon, SIGNAL(activated(QSystemTrayIcon::ActivationReason)), rootObject, SLOT(trayIconClicked(QVariant)));

And this is what I get

QObject::connect: Incompatible sender/receiver arguments
        QSystemTrayIcon::activated(QSystemTrayIcon::ActivationReason) --> ApplicationWindow_QMLTYPE_11_QML_60::trayIconClicked(QVariant)

If I completely drop the argument on the slot side, the event calls the function. But then I have no idea what ActivationReason triggred it.

A full working version of the code above is here, except that I can't hand in the reason parameter https://github.com/sturmf/qt_samples/tree/master/trayicon

Answer 1

I now subclassed the QSystemTrayicon and added a slot which emits another signal without the parameter.

#ifndef TRAYICON_H
#define TRAYICON_H
#include <iostream>
#include <QObject>
#include <QSystemTrayIcon>

class TrayIcon : public QSystemTrayIcon
{
    Q_OBJECT
public:
    explicit TrayIcon(QObject *parent = 0) : QSystemTrayIcon(parent){}

signals:
    void triggered();

public slots:
    void trayIconActivated(QSystemTrayIcon::ActivationReason reason) {
        std::cout << "activated" << std::endl;
        if (reason == QSystemTrayIcon::Trigger) {
            std::cout << "tiggered" << std::endl;
            emit triggered();
        }
    }
};

#endif // TRAYICON_H

Answer 2

In Qt5 you can connect to an anonymous function, by the way.

QObject::connect(trayIcon
    , SIGNAL(activated(QSystemTrayIcon::ActivationReason))
    , [=](QSystemTrayIcon::ActivationReason r){
              rootObject->trayIconClicked(r);
          });