Communication between C++ and QML

Question

This page shows how to call C++ functions from within QML.

What I want to do is change the image on a Button via a C++ function (trigger a state-change or however it

Answer 1

So, you could set your C++ object as a context property on the QDeclarativeView in C++, like so:

QDeclarativeView canvas;
ImageChanger i; // this is the class containing the function which should change the image
canvas.rootContext()->setContextProperty("imgChanger", &i);

In your ImageChanger class, declare a signal like:

void updateImage(QVariant imgSrc);

Then when you want to change the image, call emit updateImage(imgSrc);.

Now in your QML, listen for this signal as follows:

Image {
    id: imgToUpdate;
}

Connections {
    target: imgChanger;
    onUpdateImage: {
        imgToUpdate.source = imgSrc;
    }
}

Hope this helps.