How to pass a list, vector or array as argument in invokeMethod function

Question

Here is the documentation for the invokeMethod function.

So if I pass a string or QString type as argument, then it works. But is it possible to pass a list, vector or array of QString as argument?

P.S: The argument has to be a type of QGenericArgument and I have to use the Q_ARG macro to create the QGenericArgument object.

Simon Kraemer · Accepted Answer · 2016-03-02 14:56:20Z

3

Yes. You must register the type so that Qt can handle it correctly.

On how to register a type see qRegisterMetaType and Q_DECLARE_METATYPE

Qt types are already registered. So passing e.g. a QStringlist via Q_ARG shouldn't be a problem at all.

QString retVal;
QStringList values = QStringList() << "aaa" << "bb" << "cccc";
QMetaObject::invokeMethod(obj, "findLongest", Qt::DirectConnection,
                      Q_RETURN_ARG(QString, retVal),
                      Q_ARG(QStringList , values));

answered Mar 2, 2016 at 14:56

Simon Kraemer

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2 Comments

OnurA Over a year ago

Thanks invokeMethod function worked! And how do I process the QStringList values in the findLongest function? How can I let the function know, that it is a type of QStringList (in QML)?

Simon Kraemer Over a year ago

@OnurA I haven't worked with QML yet. Usually the invoked method is invokable or a slot. In this example it would most probably look somehow like this: QString findLongest(QStringList list);

OnurA · Accepted Answer · 2016-03-02 15:15:08Z

2

I found the following documentation. You can pass a QVariantList and then read the list in your QML file.

C++

QVariantList list;
list << 10 << QColor(Qt::green) << "bottles";


QMetaObject::invokeMethod(view.rootObject(), "readValues",
        Q_ARG(QVariant, QVariant::fromValue(list)));

QML:

 function readValues(anArray) {
    for (var i=0; i<anArray.length; i++)
        console.log("Array item:", anArray[i])
}

answered Mar 2, 2016 at 15:15

OnurA

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