QML : How to read a QList from C++

[Craig27]

I'm trying to pass QList of integer from QML to C++ code, but somehow my approach is not working.

Any inputs to solve the problem is highly appreciated.

Below is my code snippet

@_Header file_

Q_PROPERTY(QDeclarativeListProperty<int> enableKey READ enableKey) 

QDeclarativeListProperty<int> enableKey(); //function declaration
QList<int> m_enableKeys;

cpp file

QDeclarativeListProperty<int> KeyboardContainer::enableKey()
{
return QDeclarativeListProperty<int>(this, 0, &KeyboardContainer::append_list);
}

void KeyboardContainer::append_list(QDeclarativeListProperty<int> *list, int *key)
{
int *ptrKey = qobject_cast<int *>(list->object);
if (ptrKey) {
key->setParentItem(ptrKey);
ptrKey->m_enableKeys.append(key);
}
}@

[chrisadams]

QDeclarativeListProperty is not what you think it is. Don't use it.

If you were using QtQuick2, you could simply use QList<int> but in QtQuick1 you're basically out of luck. One terrible hack is to use a QVariantMap and insert(index, value). But it will be exposed in JS as an object, not an array.

Cheers,
Chris.

[Craig27]

Thanks for the reply :)

[416365416c]

For your specific case a better work around could be to just expose an append(int) function to QML directly and iterate over the JS array contents in QML.

[quote author="chrisadams" date="1355987161"]QDeclarativeListProperty is not what you think it is. Don't use it.
[/quote]

To be a little more helpful, QDeclarativeListProperty is only for lists of QObject* or pointers to QObject derived types. Not for primitive types.

Also QList<int> works fine for exporting lists from C++ to QML, better than QVariantMap. But it won't work as you'd expect for assigning to it in QML.

[Craig27]

The discussion really gave me better insight to the concepts :)