[CLOSED]Event handling from C++ to QML

[sam_dev]

Hello Everyone,

Please provide your suggestion for below scenario:

An external module sends an event to C++ thread to update an image in QML.

I can handle this event in C++ as

@
void myHandler(int eventId) {
switch(eventId)
{
case IMAGE_UPDATE:
{
setImage(); //Sets a varaible defined via Q_PROPERTY
. . .
}
break;
}
}@

How to send a signal to QML from C++ when an event is received to dynamically update the content of QML.

Edit: fixed layout issues. Please at least surround code sections with @ tags; Andre

[onek24]

You could use QMetaObject::invokeMethod to invoke a QML method.
For example: if you got QQuickView as your QMLProvider, you have to get the rootObject of it.
@QQuickView *view = new QQuickView();
QObject object = (QObject)view->rootObject();@

To invoke the method you have to do:

@QMetaObject::invokeMethod(object, "nameOfYourQmlFunction")@

If you want to give parameters you'll have to do something like that:

@QMetaObject::invokeMethod(object, "nameOfYourQmlFunction", Q_ARG(QVariant, "valueToSend"))@

You can replace the String with booleans or integers, QML transforms them to it's required format. If you want to have some values returned you'll need a Q_RETURN_ARG instead of the Q_ARG.

Function in the Documentation:
@bool QMetaObject::invokeMethod(QObject * obj, const char * member, Qt::ConnectionType type, QGenericReturnArgument ret, QGenericArgument val0 = QGenericArgument( 0 ), QGenericArgument val1 = QGenericArgument(), QGenericArgument val2 = QGenericArgument(), QGenericArgument val3 = QGenericArgument(), QGenericArgument val4 = QGenericArgument(), QGenericArgument val5 = QGenericArgument(), QGenericArgument val6 = QGenericArgument(), QGenericArgument val7 = QGenericArgument(), QGenericArgument val8 = QGenericArgument(), QGenericArgument val9 = QGenericArgument())[static]@

For further information please read:
"Calling Functions":http://qt-project.org/doc/qt-4.8/qtbinding.html#calling-functions
"Receiving Signals":http://qt-project.org/doc/qt-4.8/qtbinding.html#receiving-signals
"Supportet Datatypes":http://qt-project.org/doc/qt-4.8/qtbinding.html#supported-data-types

[sam_dev]

Thanks onek24...

I understood your point.

[onek24]

Sorry, i didn't see that it's a thread from more than 1 month ago. I hope that i could still help you and/or someone else who didn't understand how to invoke QML methods.