Use signals or Q_PROPERTY to update QML objects

Question

I'm very frequently receiving data from a server. This data is mainly composed of numbers. Each of them is corresponding to a QML object that would need to be updated.

What would be the best course of action between Q_PROPERTY and signals in order to update the QML objects from the C++ files?

Yes. See [Qt Binding documentation](http://doc.qt.io/qt-4.8/qtbinding.html) — Grégoire Borel, Feb 04 '16 at 15:01

score 4 · Accepted Answer · answered Feb 05 '16 at 12:44

Quite nice way is to use binding to C++ object from QML.

F.ex. You have data class that should be shown to user as some qml object.

You have C++ class with data and appropriate properties:

class MyData
{
    Q_OBJECT
    Q_PROPERTY(qreal number READ number NOTIFY numberChanged)
    ....
    //here you implement setter function that emits numberChanged() signal

};

You expose your data to qml via some helper classes or directly:

view->rootContext()->setContextProperty("myData", myDataObject);

Than you use binding to object in your qml:

Text 
{
    text: myData.number 
}

And now you can change the data in object of MyData class and your qml updates automatically.

Use signals or Q_PROPERTY to update QML objects

1 Answers1