[Qt-qml] Extending with C++, basic QML list type question

[bea.lam at nokia.com]

On 22/11/2011, at 6:15 PM, ext Harri Pasanen wrote:
> [snip]
> I reproduced my problem with the PieChart example.  The modified app.qml is as follows:
> 
> // --------------------------------------------
> import Charts 1.0
> import QtQuick 1.0
> 
> Item {
>    width: 300; height: 200
> 
>    PieChart {
>        id: pie
>        anchors.centerIn: parent
>        width: 100; height: 100
> 
>        slices: [
>            PieSlice {
>                anchors.fill: parent
>                color: "red"
>                fromAngle: 0; angleSpan: 110
>            },
>            PieSlice {
>                anchors.fill: parent
>                color: "black"
>                fromAngle: 110; angleSpan: 50
>            },
>            PieSlice {
>                anchors.fill: parent
>                color: "blue"
>                fromAngle: 160; angleSpan: 100
>            }
>        ]
>    }
> 
>    Component.onCompleted:  {
>      console.log("completed")
>      console.log(pie.slices)
>      console.log(pie.slices[1].color)
>    }
> }
> 
> 
> When I run chapter5-listproperties project with this, it spits out
> 
> TypeError: Result of expression 'pie.slices[1]' [undefined] is not an object.
> 


Ah, I see - in this case, the PieChart class needs to pass an AtFunction as well as a AppendFunction to the QDeclarativeListProperty constructor. The AtFunction will provide index-based access to objects within the list. In the BirthdayParty example, this functionality was added automatically, since the example used the convenience constructor of QDeclarativeListProperty.

cheers,

Bea