Call a qml function from C++.

mrdebug

I normally use this line of code to invoke a qml function from c++ and all works well.
@QMetaObject::invokeMethod((QObject*)(this->rootObjects().first()), "CallOk");@
But my situation in a bit different. From the main qml file, by clicking on a button, I load a second qml file.
How can I call its functions from c++?
This line of code does not work.
#QMetaObject::invokeMethod((QObject*)(this->rootObjects().first()), "CallOk");#
I have tried
@this->rootObjects().first()->findChild<QObject*>("aaa");@
using the name of the object but does not work.
Can you suggest me the right way?

Babalas

Use slots or Q_INVOKABLE.
c++
@class Blah {
....
public slots:
void iveBeenClicked()
};@

Pass class to qml
@
Blah foo;
view->rootContext()->setContextProperty("myblah", &blah);
@

Qml
@
Button {
onClicked: myblah.iveBeenClicked()
}

Button {
id: lateButton
}

Component.onCompleted: lateButton.clicked.connect(myblah.iveBeenClicked())
@

mrdebug

Sorry but it isn't my situation.
I need to call a qml function from c++.
This line of code
@QMetaObject::invokeMethod((QObject*)(this->rootObjects().first()), "CallOk");@
works only with a function in the main qml file.
If you load a second qml file, the functions in it are not accesible from C++.

Gennon

Why not emit a signal from C++ that the QML file catches and then runs your function?

mrdebug

It's a nice idea but I haven't find an example on how to connect a qml function to a c++ signal.
Connect function seems to not be available in qml.

Gennon

You just make a C++ object that emits a signal the normal way, then make use of "Connections":http://qt-project.org/doc/qt-5/qml-qtqml-connections.html in QML. You need to have the "class available to QML":http://qt-project.org/doc/qt-5/qtqml-cppintegration-contextproperties.html.

So if you have a signal runFunction in your C++ class you can then just connect to it in your QML file like this:

@
Connections {
target: myCppClass
onRunFunction: myQMLFuntion();
}
@

Hope it helps!

p3c0

[quote author="mrdebug" date="1405861088"]

I normally use this line of code to invoke a qml function from c++ and all works well.
@QMetaObject::invokeMethod((QObject*)(this->rootObjects().first()), "CallOk");@
But my situation in a bit different. From the main qml file, by clicking on a button, I load a second qml file.
How can I call its functions from c++?
This line of code does not work.
#QMetaObject::invokeMethod((QObject*)(this->rootObjects().first()), "CallOk");#
I have tried
@this->rootObjects().first()->findChild<QObject*>("aaa");@
using the name of the object but does not work.
Can you suggest me the right way?[/quote]

Try this,
@
QMetaObject::invokeMethod((QObject*)(engine.rootObjects().at(0)->findChild<QQuickItem*>("myObject")), "callMyMethod");
@

Provided you have given an objectName to the Item (here myObject)

mrdebug

@
Connections {
target: myCppClass
onRunFunction: myQMLFuntion();
}
@

Works perfectly!