Problem with ListView dynamic height

[vivekmalik2466]

I am having a ListView and have applied a scroll bar on it. The scrollbar is working fine if each row is of same height. But when the heights of rows vary then scrollbar starts behaving unexpectedly. I found out that the ListView redraws its elements while flicking. So the contentHeight changes it's value in case of different row heights while scolling. I am using Qt 4.7 and QtQuick 1.0 versions of Qt and QML respectively.

@Item {
id: myItem
property variant items

ListView {
id: list
anchors.fill: parent
clip: true
model: items
delegate: trackDelegate
focus: true
boundsBehavior: Flickable.StopAtBounds
}
}

ScrollBar {
id: verticalScrollBar
target: list
clip: true
}
}

And scroll bar code is
// import QtQuick 1.0 // to target S60 5th Edition or Maemo 5
import Qt 4.7
Item {
property variant target
width: 8
anchors.top: target.top
anchors.bottom: target.bottom
anchors.margins: 1
anchors.rightMargin: 2
anchors.bottomMargin: 2
anchors.right: target.right
visible: (track.height == slider.height) ? false : true
Image {
id: scrollPath
width: 2
anchors.top: parent.top
anchors.bottom: parent.bottom
anchors.horizontalCenter: parent.horizontalCenter
source: "qrc:/resources/buttons/slider2.png"
}
Item {
anchors.fill: parent
Timer {
property int scrollAmount
id: timer
repeat: true
interval: 20
onTriggered: {
target.contentY = Math.max(0, Math.min(target.contentY + scrollAmount,
target.contentHeight - target.height));
}
}
Item {
id: track
anchors.top: parent.top
anchors.topMargin: 1
anchors.bottom: parent.bottom
width: parent.width
MouseArea {
anchors.fill: parent
onPressed: {
timer.scrollAmount = target.height * (mouseY < slider.y ? -1 : 1)
timer.running = true;
}
onReleased: {
timer.running = false;
}
}
Image {
id:slider
anchors.horizontalCenter: parent.horizontalCenter
source: "qrc:/resources/buttons/slider.png"
width: parent.width
height: Math.min(target.height / target.contentHeight * track.height, track.height) < 20 ? 20 : Math.min(target.height / target.contentHeight * track.height, track.height)
y: target.visibleArea.yPosition * track.height
MouseArea {
anchors.fill: parent
drag.target: parent
drag.axis: Drag.YAxis
drag.minimumY: 0
drag.maximumY: track.height - height
onPositionChanged: {
if (pressedButtons == Qt.LeftButton) {
target.contentY = slider.y * target.contentHeight / track.height;
}
}
}
}
}
}
}

@