QQmlListProperty constructor doesn't accept my arguments

[themts]

TestItemClass:

class TestItem : public NChartRenderItem
{
    Q_OBJECT    
private:
    QOpenGLBuffer *m_vertexBuffer = NULL;

public:
    TestItem();
    ~TestItem();

    // NChartRenderItem interface
public:
    bool createVertexBuffer(int bufferSize);
    bool renderItem();
};

NChartRenderItem-Class:

class NChartRenderItem : public QObject
{
    Q_OBJECT
public:
    explicit NChartRenderItem(QObject *parent = 0);
    ~NChartRenderItem();

    virtual bool createVertexBuffer(int bufferSize) = 0;
    virtual bool renderItem() = 0;

signals:

public slots:
};

[A Former User]

Hmm can u show me the constructor implementation?

[themts]

At this moment the constructors are just empty.

TestItem::TestItem()
{
}

[A Former User]

@themts said:

QQmlListProperty<TestItem> TestClass::lstTestItems() const
{
return QQmlListProperty<TestItem>(this, 0, &TestClass::count_lstTestItems, &TestClass::at_lstTestItems);
}

Why this?

In my impelentation it looks diffrent.

<pre><code>
//implementation of the getter
QQmlListProperty<Object> YourClass::fields() {
return QQmlListProperty<Object>(this, this->m_fields);
}
</code></pre>

[themts]

QQmlListProperty has 3 constructor. I'm using this one:
http://doc.qt.io/qt-5/qqmllistproperty.html#QQmlListProperty-4

That way I can use it as a "virtual" list.
Anyway, even if I use it your way - which is not recommended - it shows the same error.
"Generally this constructor should not be used in production code, as a writable QList violates QML's memory management rules. However, this constructor can be very useful while prototyping."

QList<TestItem*> m_lstTestItems;

return QQmlListProperty<TestItem>(this, this->m_lstTestItems);

[A Former User]

OK, thanks for your hints. I will definitely change this. I saw this in different sample codes. But my c++ and QT knowledge is very nooby :) Sorry that i can't help u. Not really an idea.

[A Former User]

Can u show me the constructor implementation of your NChartRenderItem class?

[themts]

I really don't understand why it's not working.
I even tried to use Q_PROPERTY(QQmlListProperty<QObject> ... -> same result

I don't get it. The error-message (C2665) seems to be wrong as well: it says 5 overloads.
Actually there are only 4.

Does anyone has an idea?
Btw. I want to use QQmlListProperty as a datamodel for a listview.

[swegmann]

Can you show us the full error message of the compiler for the case where you give it the count and at functions? I think there might be some helpfull information about this issue.

[themts]

solved :-)
no one saw it ;-)

public:
    QQmlListProperty<TestItem> lstTestItems() const;

this can't be const. Thats it.