QtQuick, QML and C integration: how to make public variables definied inside .h file visible in QM-CodePudding

After integration C and QML using the way described here:

I have noticed only .h methods are visible outside class (from QML level), I have no access for public variables. After research I found that:

void QQmlContext::setContextProperty(const QString &name, const QVariant &value)

Is this way proper?

If not, how can I get access to my class public variables from QML level ?

Supposedly I can create functions for this purpose, but I don't like this way. It looks for me like way around...

CodePudding user response：

In the following example, I wanted to expose the C qVersion() from QtGlobal to QML as System.qtVersion.

//System.h
#ifndef System_H
#define System_H
#include <QObject>
class System : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QString qtVersion READ qtVersion CONSTANT)
public:
    System(QObject* parent = nullptr);
    QString qtVersion() const;
};
#endif

//System.cpp
#include "System.h"
System::System(QObject * parent) :
    QObject(parent)
{
}
QString System::qtVersion() const
{
    return qVersion();
}
#endif

```c  
//main.cpp
    //...
    qmlRegisterSingletonType<System>("qmlonline", 1, 0, "System", [](QQmlEngine*,QJSEngine*) -> QObject* { return new System(); } );

I can access the above in QML with the following snippet:

import QtQuick
import QtQuick.Controls
import qmlonline
Page {
    Text {
        text: System.qtVersion
    }
}

You can try the QML portion online

For other examples of C wrappings to QML checkout my GitHub projects: