ListView: Change anchor onCurrentIndexChanged

[didu]

hello,

I wanna change the anchor of my ListView for a specifique Index value.
But when "anchors.top" is change the currentIndex is "reset" to the last value.

For exemple:

        onCurrentIndexChanged: {
            console.log("currentIndex : " + currentIndex);
            if (currentIndex == 0)
                anchors.top = banner.bottom
            else
                anchors.top = image.bottom
        }

Runtime output:

//current currentIndex = 2
//set currentIndex = 0 from qml
currentIndex :  0
currentIndex :  2

it look like anchor.top reset the currentIndex ?
Is there any better way to change the anchor when index is changed ?

Thanks in advance