How can serveral same qml objects references to one C++ object?

[jackmack]

Hi together,

I have a question about instantiating several qml objects but only references to one C++ object.
I have written a C++ object for displaying a webcam using openCV. I have successfully registered the C++ object and I'm able to embed it in qml.

My C++ application (using QDeclativeView) uses QML as it's UI. The UI is a flickable one and you can switch between several pages. Some pages embeds the C++ object.

The problem: Every embedded C++ object has its own C++ instance!

I want to have that every embedded C++ object references only to one C++ instance.

Example:

test.qml:

Row {
spacing: 5

MyCamera {
id: camera1
with: 100
height: 100
number: 0
}

MyCamera {
id: camera2
with: 100
height: 100
number: 0
}
}

Result:
The constructor of the C++ class is called twice.

What I want:
Camera1 and Camera2 references to one C++ instance.

Why?
My "logical layer" which instantiates the C++ object "paints" something into the one and only camera widget. And "Camera1" and "Camera2" should be displaying it.

Thx
jackmack

[z.emb]

You create two MyCamera items. The qml engine instantiates the items. So there are two C++ instances of your QQuickItem subclass.

You can add your "logical layer" to the qml context through the qml view so the qml items can interact with its properties.

[sierdzio]

This is how QML works. Every component you declare is a separate instance.

You could experiment with transforming your class into a singleton, or you can instantiate the component in C++ and passing instances to GUI, or maybe a clever use of Loader could help:
@
MyCamera {
id: globalCamObject
}

Loader {
id: camera1
sourceComponent: globalCamObject
}

Loader {
id: camera2
sourceComponent: globalCamObject
}
@