Signal from QML to C++ slot, cannot find the QML signal

Question

I got a signal in QML and I want to connect to a slot defined in C++. However my code is failing and I'm receiving the error:

QObject::connect: No such signal QDeclarativeContext::sent() in ../qt_cpp/mainwindow.cpp:66

Here is a c++ code snippet:

message_reading test;
QDeclarativeView tempview;
tempview.setSource(QUrl("qrc:/qml/media_screen.qml"));
QObject *item = tempview.rootContext();
QObject::connect(item, SIGNAL(sent()),
&test, SLOT(readMediaJSONDatabase(QString&)));

And here is a QML code snippet:

Image {
    id: bluetooth
    source: "images_mediahub/footer_icons/bluetooth_normal.png"
    signal sent(string msg)
    MouseArea {
        anchors.fill:  parent
        onClicked: {
            bluetooth.sent(Test.medialibrarydb.toString())
            info_load.source="./bluetooth.qml"
        }
    }
}

Gustavo Niemeyer · Accepted Answer · 2013-08-28 14:11:49Z

1

The SIGNAL macro call in the connect line must inform the parameter explicitly, with SIGNAL(sent(QString)).

In addition, the signal is being emitted by the created object, but code snippet you provided is trying to connect it in the context object instead. You'll need something along the lines of:

QObject *tempitem = tempview.rootObject();

There's a complete example covering that in the documentation.

edited Aug 28, 2013 at 14:11

answered Aug 28, 2013 at 4:10

Gustavo Niemeyer

23.2k5 gold badges59 silver badges46 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

zero Over a year ago

No, I tried to add type SIGNAL(sent(QString)) there, and it not working. report same error message BTW, compile success, but when open the application window, then return this error message.

Gustavo Niemeyer Over a year ago

Ah, sorry, now I notice you're also trying to attach it to the context, which isn't what you want. Will update the answer.

zero Over a year ago

thank you anyway. I got some new update... but still learning this .

Gustavo Niemeyer Over a year ago

Your update actually asks a different question. I believe the two points in the answer actually solve your original one.

Collectives™ on Stack Overflow

Signal from QML to C++ slot, cannot find the QML signal

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related