Setting context property for multiple qml files - qt

Question

I have a main.qml and inside that i have two banners(titlebanner and bottombanner) as shown in below.
Window {
id: main
visible: true
Image {
source: "qrc:/banner.png"
anchors.fill: parent
}
TitleBanner {
x:0
y:10
}
BottomBanner {
x:0
y:420
}
}
In TitleBanner.qml, i have below code
Item {
Rectangle {
id : id_title_banner
property real value : titlebanner.title
Image {
source: "qrc:/banner_title.png";
}
//todo:: some animation stuffs on 'value' later
}
}
In BottomBanner.qml, i have below code
Item {
Rectangle {
id : id_bottom_banner
property real value : bottombanner.title
Image {
source: "qrc:/banner_bottom.png";
}
//todo:: some animation stuffs on 'value' later
}
}
In C++ side, I am keeping two separate objects(for later flexibility) for both title banner and bottom banner. I set the root context property to expose the title banner objects from C++ to qml as below
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
//create title banner object
CTitleBanner *objTitleBanner = new CTitleBanner();
//create bottom banner object
CBottomBanner *objBottomBanner = new CBottomBanner();
QQmlApplicationEngine engine;
engine.rootContext()->setContextProperty("titlebanner", objTitleBanner);
engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
return app.exec();
}
My question is, how can we set context property for both titlebanner and bottombanner qml files separately instead of setting it to root context ? My concern is at later point if more banner comes, I set it to rootContext. Is it a proper way of doing ? How can we create seperate context for each banner ?

Answer 1

Your assumption:
it replaces above context property.
is wrong:
// in main.cpp
QObject* obj1 = new QObject();
QObject* obj2 = new QObject();
engine.rootContext()->setContextProperty("obj1", obj1);
engine.rootContext()->setContextProperty("obj2", obj2);
qDebug() << "obj1" << obj1 << engine.rootContext()->contextProperty("obj1").value<QObject*>();
qDebug() << "obj2" << obj2 << engine.rootContext()->contextProperty("obj2").value<QObject*>();
// in main.qml
Component.onCompleted: console.log(obj1, obj2)
// output:
obj1 QObject(0x22d8c768) QObject(0x22d8c768)
obj2 QObject(0x22d8c778) QObject(0x22d8c778)
qml: QObject(0x22d8c768) QObject(0x22d8c778)
Both objects are there, with the right identifier.
Personally I don't like contextProperties since they are easily to be shadowed e.t.c. - I rather register my CPP models as singletons so I can import them at the places where I really want to have access to them. Though there are downsides of those singletons. (e.g. qmlscene will fail to import them)