How to Pass the object from QML to CPP file?

Mathan M

Hi,
I am developing an app.
Query:
How to pass the object from QML to CPP file, what will be object type in QT?

Code:
Login.QML
function metPassObject()
{

var myCar = new Object();
myCar.make = "Ford";
myCar.model = "Mustang"
myCar.year = 1969;

objQtCPPSearchVOne.metPassObject(myCar);

}

.H file:
Q_INVOKABLE void metPassObject (type parameter)- what will be the parameter type?

.CPP file:
void metPassObject(type parameter)
{
//How to access the object?
}

I am an .Net/C# guy, So my approach is based on that. Am I doing right code or If I am wrong, Pls correct me with concept.

Thanks is Advance.

medyakovvit

@Mathan-M I think, there are different ways for that, some of them:

#1
use QVariantMap on C++ side:
Qml:

function metPassObject()
{
    var myCar = {make: "Ford"; model: "Mustang"; year: 1969};
    objQtCPPSearchVOne.metPassObject(myCar);
}

C++:

Q_INVOKABLE void metPassObject (QVariantMap carMap){
    qDebug() << varMap.value("make").toString();
    qDebug() << varMap.value("model").toString();
    qDebug() << varMap.value("year").toInt();
}

#2
Create C++ class derived from QObject with Q_PROPERTY. And register it to qml with qmlRegisterType():

Car class:

class Car : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString make READ make WRITE setMake NOTIFY makeChanged)
    Q_PROPERTY(QString model READ model WRITE setModel NOTIFY modelChanged)
    Q_PROPERTY(int year READ year WRITE setYear NOTIFY yearChanged)

//...
// defining of setters, getters, signals, and data members for properies
//...
}

Then, maybe somewhere in main.cpp:

qmlRegisterType<Car>("my.car", 1, 0, "Car");

Create car dynamically on qml side:

function metPassObject()
{
   var aCar = Qt.createQmlObject('import my.car1.0; Car{make: "Ford"; model:"Mustang"; year: 1969}', repeaterModel, "");
     objQtCPPSearchVOne.metPassObject(myCar);
}

and in C++ side:

Q_INVOKABLE void metPassObject (Car* aCar){
    qDebug() << "Make: " << aCar->make();
    qDebug() << "Model: " << aCar->model();
    qDebug() << "year: " << aCar->year();
}

#3
Send simpl types like string and int to C++ from Qml:

Qml:

function metPassObject()
{
     objQtCPPSearchVOne.metPassObject("Ford", "Mustang", 1969);
}

And C++:

Q_INVOKABLE void metPassObject (QString aMake, QString aModel, int aYear){
    Car* myCar = new Car(aMake, aModel, aYear);
    //...do smthg
}

Mathan M

Hi @medyakovvit ,

Now I can pass the objects.

Thanks a Lot and really appreciate your efforts.

Mathan