Can not get parameters from connected signal

Cyrille de Brebisson

Hello,

I have a C++ object, dutifully registered as a singleton with the qml system.
This object has a newDevice signal with 2 parameters (the second one being a Qml registered enum):

class obj : public QObject {
Q_OBJECT
Q_SIGNALS:
void newDevice(int linkId, enumType type);

in my main qml code, I connect a function to the onNewDevice signal like so:

    Component.onCompleted: {
        HPACModel.onNewDevice.connect(function(linkId, type) { console.log("new device id:", linkId, "type:", type);  }
}

However, it does not seem to do what I want. When I emit a newDevice(1,1) for example, my function is called, but it displays in the console:
qml: new device id: undefined type: undefined

Can you tell me what I am doing wrong?

Thanks

sierdzio

Try with Connections:

Connections {
  target: HPACModel

  onNewDevice: {
    console.log("new device id:", linkId, "type:", type)
  }
}

Cyrille de Brebisson

Hello,

Nope, sorry, but I still get the same result :-(

Strangely enough, if I change the type from my current enumType to an int, then both my and your versions do work... So it looks like it has something to do with the enum... Any ideas?

Cyrille

J.Hilk

@Cyrille-de-Brebisson
did you register your enum via qmlRegisterUncreatableType ?

sierdzio

I that enum registered with Q_ENUM, too?

Cyrille de Brebisson

Hello,

Here is the "real" code...
The enum with the Q_ENUM

class HPACDevices : public QObject {
Q_OBJECT
public:
HPACDevices(QObject *parent=nullptr): QObject(parent) {}
enum HPACDeviceTypes
{
Unknown= 0,
Pinky,
Brain,
Kazar
};
Q_ENUMS(HPACDeviceTypes)
};

The registration of the class in main.cpp reads as follow...
qmlRegisterType<HPACDevices>("HPACDevices", 1, 0, "HPACDevices");

I do not have any calls to qmlRegisterUncreatableType. Where should that go and what parameters should it have?

Thanks

sierdzio

@Cyrille-de-Brebisson said in Can not get parameters from connected signal:

Q_ENUMS(HPACDeviceTypes)

Q_ENUM, not Q_ENUMS. The difference is small but very important.

Cyrille de Brebisson

Hello,

changing from Q_ENUMS to Q_ENUM did change some things (some of the other displays that I had changed from 2 to HPACDeviceTypes(Brain)), however my core issue, the fact that I can not read the parameters in my Qml signal handler still persists :-(

(Ps: I have switch to the "connection" scheme)...

Cyrille

J.Hilk

@Cyrille-de-Brebisson said in Can not get parameters from connected signal:

I do not have any calls to qmlRegisterUncreatableType. Where should that go and what parameters should it have?

Thanks

something along this

qmlRegisterUncreatableType<myClass>("CppEnums",1,0,"Enums","Enum is not a type");

inside your qml file you'll have to import CppEnums to have access to the enums

import CppEnums 1.0

...
Enums.EnumName

also you Enums need to start with a capital letter to work in qml

Cyrille de Brebisson

Hello,

Nope, using qmlRegisterUncreatableType does not help. The symptoms are the same with the parameters being undef.
Note, with the qmlRegisterType I have no issues accessing the enum in Qml. The problem is that the arguements that are passed to my signal handler are undefined (as per Qml) if/when the C++ side of the signal handler defines them as my enum type. However, they are "ok" if they are integers.

Is a signal not able to use anything else than "basic types"?

Cyrille