Get SpinBox value from qml into C++

[Ahti]

I want to read a value of SpinBox inside c++ code how would I do it ?

main.cpp:

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;    
    return app.exec();
}

main.qml:

SpinBox {
          id: new_slider
          editable: true
          value: 60
          from: 1
          to: 60
          textFromValue: function(value){ return value + " min"; }
}

[sierdzio]

Here are some docs on this subject:

• integrating C++ and QML
• engine context properties

[Pradeep P N]

Hi @Ahti

You can even use public slots: in QML, below is example.

• main.cpp

    MySpinBoxValue cppClass;
    engine.rootContext()->setContextProperty("cppObject", &cppClass);

• MySpinBoxValue.h

    public slots:
        void spinBoxQmlValue(int value);

• MySpinBoxValue.cpp

    void MySpinBoxValue::spinBoxQmlValue(int value)
    {
       qDebug() << Q_FUNC_INFO << value << endl;
    }

• QML

    SpinBox {
        id: new_slider
        editable: true
        value: 60
        from: 1
        to: 60

        // This is to update value when ever there is change
        onValueChanged: {
            console.log("SP_BOX_VAL FROM QML :: ", value)
            cppObject.spinBoxQmlValue(value);
        }
        
        // This is to send initial Value to QML on APP Launch.
        Component.onCompleted: {
            cppObject.spinBoxQmlValue(value);            
        }
    }

Output :

QML debugging is enabled. Only use this in a safe environment.
void MySpinBoxValue::spinBoxQmlValue(int) 60 

qml: SP_BOX_VAL FROM QML ::  59
void MySpinBoxValue::spinBoxQmlValue(int) 59 

qml: SP_BOX_VAL FROM QML ::  58
void MySpinBoxValue::spinBoxQmlValue(int) 58 

qml: SP_BOX_VAL FROM QML ::  57
void MySpinBoxValue::spinBoxQmlValue(int) 57 

qml: SP_BOX_VAL FROM QML ::  58
void MySpinBoxValue::spinBoxQmlValue(int) 58 

qml: SP_BOX_VAL FROM QML ::  59
void MySpinBoxValue::spinBoxQmlValue(int) 59 

All the best.