4-5 Control GPIO using C++ Class in Qt Project

Qt - GPIO Button

Please reference to the Repository :

The most important concept in this project is how to link QML to our C++ class. All of our GPIO control functions through Linux driver are all inside the C++ class.

The below are some important concepts in the above programs.

Register a C++ class to use from QML

If you need to register a C++ class to use from QML, you can declaring your QQmlApplicationEngine and assign it as the parent of your object.

Reference :

qmlRegisterType

Once this is registered, the type can be used in QML.

tip

The above reference about QQmlApplicationEngine might not appicable to Qt563.
However, the source code below has been verified on Qt563, please use them directly.

in main.cpp

#include <rzgpio.h>
...
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;   

RzGPIO* rzgpio = new RzGPIO(&engine);
QQmlContext* context = engine.rootContext();
context->setContextProperty("RzGPIO", rzgpio);

engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

return app.exec();
}

main.qml :

Button {
x:70
y:200
...
onClicked : {
        if (thismain.led2 === 0) {
            RzGPIO.Write(2, 1);
            thismain.led2=2;
            }
            else {
                RzGPIO.Write(2, 0);
                thismain.led2=0;
                }

            }

QTimer :

Reference to Qt "Analog Clock" under Examples/gui/analogclock/, we can add timer in Qt Control.

  Timer {
        interval: 100; running: true; repeat: true;
        onTriggered: clock.timeChanged()
    }