QtQUick and Raspberry, how to use the main loop

DarkPatate

Hello,
I'm used to code with classic Qt, but I just started with QML and Qt Quick.

My aim is to use my app on a Rpi with a LCD screen. But I don't see how to integrate the RPi part in the program. I want to add some actions in the main loop of the application (getting some information from I2C).

Here is my main.cpp (without includes)

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QGuiApplication app(argc, argv);

    StrategiesModel::declareQML();
    Communication::declareQML();
    QQuickStyle::setStyle("Material");

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

I created the Communication class to that purpose, but I'm not sure if it's the right way.

With classic Qt, I would use the Windows Object and add some signals and slots. But how can I achieve that with QML (keeping interactions beetween QML interface and C++ program)?

Thanks in advance.

mrjj

Hi
did you read this ?
http://doc.qt.io/qt-5/qtqml-cppintegration-topic.html
QML also have signals and slots
http://doc.qt.io/qt-5/qtqml-syntax-signals.html

DarkPatate

@mrjj I found many docs but not your links, thanks!
For the first one, I did the same, so I now it's the right way now.

For the second one, it'll be really helpfull, thanks again!

One more question: I now how to access to property signal of my class in QML with Q_PROPERTY(State state READ state WRITE setState NOTIFY stateChanged). But how can I access to signals/slots not linked to a property? I have to use Q_INVOKABLE?

Thanks in advance.

mrjj

@DarkPatate said in QtQUick and Raspberry, how to use the main loop:

Q_INVOKABLE

Hi
Yes that can work.
https://stackoverflow.com/questions/9341005/connecting-c-with-qml-using-q-invokable?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa