Not understanding QtScript

[zephod]

I'm trying to learn about QT script and I'm clearly not understanding something basic.
Consider the following code:



#include <iostream>

#include <QApplication>
#include <QtScript>
#include <QObject>

using namespace std;

class MyClass : public QObject
{
public:
int x;
};

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

MyClass mc;
mc.x = 0;

QScriptEngine eng;
QScriptValue scriptClass = eng.newQObject(&mc);
QScriptValue global = eng.globalObject();
global.setProperty("myClass", scriptClass);

QScriptValue res = eng.evaluate("myClass.x == 0");
if (res.isBoolean())
{
cout << "res is 0 = " << res.toBoolean() << endl;
}
else
{
cout << "res is not boolean!!!" << endl;
}
return 0;
}


This prints "res is 0 = 0" when run. It seems that the script engine does know about myClass but the value of myClass.x is not set.
Can someone enlighten me?

Thanks,
Steve

[wysota]

"x" needs to be a regular Qt property for this to work.

[zephod]

Thanks wysota!

Changed MyClass to



class MyClass : puble QObject
{
Q_PROPERTY(int x);
};


and


mc.x = 0;

to


mc.setProperty("x", 0);


and now its working.

[wysota]

That's not entirely correct. Should be:


class MyClass : public QObject
Q_OBJECT
Q_PROPERTY(int x READ x WRITE setX)
public:
MyClass(QObject *parent = 0) : QObject(parent) { m_x = 0; }
int x() const { return m_x; }
public slots:
void setX(int _x) { m_x = _x; }
private:
int m_x;
};

mc.setX(0);

[zephod]

It seems that what I did caused some dynamic properties to be created so that my program gave the answers I expected without actually being correct.
See my other post on Q_PROPERTY and Q_OBJECT.

[wysota]

I know, thus if you use my code above, it will work as expected.