How to control onClicked in qml with C ++ code ?

[LeeK]

i want to control onClicked in qml with c++ code, without touch the display.
but, i don't know how.
please tell me....

ex)
int main() {
...
callclick();
...
}

if i do this, call onClick in QML code.

[J.Hilk]

hi @LeeK and welcome

first of, you do not provide enough information, for any good help.

Let me ask this, do you know how to send signals from a c++ class to your qml file?
If not, you may want to read through this first.
https://doc.qt.io/qt-5/qtqml-cppintegration-interactqmlfromcpp.html

[LeeK]

hi @J-Hilk .
First, thanks for the answers.
I will provide additional information.

my sample qml code :

Rectangle {
     id: rectsampleid
     height: 500
     width: 500
     visible: true

    function myQmlFunction(msg) {
        console.log("Got message:", msg)
        return "some return value"
    }

    MouseArea {
        anchors.fill: parent
        onClicked: {
            Qt.quit();
        }
    }

    Text {
        text: qsTr("Hello World")
        anchors.centerIn: parent
    }
}

and my sample main.cpp :

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlComponent>
#include <QDebug>
#define QARG(object,returnedValue, msg) QMetaObject::invokeMethod(object, "myQmlFunction", Q_RETURN_ARG(QVariant, returnedValue), Q_ARG(QVariant, msg))

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    QQmlComponent component(&engine, QUrl(QLatin1String("qrc:/main.qml")));
    //engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    QObject *mainPage = component.create();
    QObject* item = mainPage->findChild<QObject *>("buttonTest");

    QVariant returnedValue;
    QVariant msg = "Hello from C++";
    QARG(mainPage, returnedValue, msg);
    qDebug() << "QML function returned:" << returnedValue.toString();

    return app.exec();
}

The code is roughly the sample code.
i want to execute the onClicked in the MouseArea in the QML without touch to display.

I want to do any method call that gave the signal.
Otherwise, i want to control the Qt sublayer to achieve the desired result.
but, i don't know how.....
And i have already seen the tutorial website you provided, but I couldn't get the information I needed.

I keep searching and studying, but I can't think of any way.
Please help me...

[J.Hilk]

@LeeK said in How to control onClicked in qml with C ++ code ?:

hi @J-Hilk .
First, thanks for the answers.
I will provide additional information.

thanks

And i have already seen the tutorial website you provided, but I couldn't get the information I needed.

I doubt that, there is exactly an example of what you need:
https://doc.qt.io/qt-5/qtqml-cppintegration-interactqmlfromcpp.html#invoking-qml-methods

and here's a working program for you:

//main.cpp
#include <QApplication>
#include <QQmlApplicationEngine>

#include <QDebug>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QQmlApplicationEngine engine;

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

    QObject *rootElement = engine.rootObjects().first();
    QVariant returnedValue;
    QVariant msg = "Hello from C++";
    QMetaObject::invokeMethod(rootElement, "myQmlFunction",
            Q_RETURN_ARG(QVariant, returnedValue),
            Q_ARG(QVariant, msg));

    qDebug() << "QML function returned:" << returnedValue.toString();

    return app.exec();
}

//main.qml
import QtQuick 2.11
import QtQuick.Window 2.2

Window
{
    id:rootWindow
    width: 400
    height: 250

    visible:  true

    function myQmlFunction(msg) {
            console.log("Got message:", msg)
            return "some return value"
        }
}

[LeeK]

okay, i know.
The tutorial you provided is what I saw in the past, and I wrote the sample code through it.
However, what I want to ask is whether i can control "onClicked" in qml with C ++ code based on that sample code, not that the sample code is wrong.

[J.Hilk]

@LeeK ah, I got you now ;-)

The answer is yes and no

you can't directly access the onClicked function, but you could create a standalone function that is called/executed by onClicked and can also be called from c++

Or you could potentially emit the clicked signal manually, I'm unsure about that as I haven' tried that one yet.

[LeeK]

@J-Hilk okay.
"you can't directly access the onClicked function."
maybe, this is answer for my questions.
thanks for the replies.