ListView Item Manual Positioning Animations QML

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Manual ListView Item Positioning

Introduction

Let's say for instance instead of wanting a plain ListView with its items laid out horizontally and linearly, you instead want a list to respond so that when one item is selected, that item animates towards a different position (lower y value). This item is singled out and when a different item is selected, they swap places. This was useful for my case of KDE's login manager theme, where the items were user face images.

Implementation

Here we create a ListView, a simple array just as filler for what your model will actually be, a delegate with an image and text item, and then we manually set the y and x position of them.

QML Code

import QtQuick 1.0

Item {
 width: 600
 height: 600
 property int itemWidth: 50

ListView {
 id: view
 model: new Array(1,2,3,4,5,6,7,8)
 delegate: item
 anchors {
 top: parent.top;
 topMargin: 10;
 horizontalCenter:
 parent.horizontalCenter;
 bottom:
 parent.bottom;
 }
 width: model.length * itemWidth + (model.length - 1) * spacing
 spacing: 2
 orientation: Qt.Horizontal
 snapMode: ListView.SnapOneItem
 highlightRangeMode: ListView.ApplyRange
 interactive: false
 Component.onCompleted: currentIndex = -1;
 }


 Component {
 id: item

 Rectangle {
 width: itemWidth
 height: 50
 color: "red"
 x: {
 if (ListView.isCurrentItem) {
 if (view.flickingHorizontally) {
 (view.width/2)- (width/2)
 } else {
 (view.width/2)-(width/2)
 }
 } else {
 if ( view.currentIndex==-1) {
 index * (width + view.spacing)
 } else {
 if ( index < view.currentIndex) {
 index * (width + view.spacing) + (width/2)
 } else {
 index * (width + view.spacing)- (width/2)
 }
 }
 }
 }
 y: ListView.isCurrentItem ? 200 : 0
 Behavior on x { SpringAnimation { spring: 4; damping: 0.4 } }
 Behavior on y { SpringAnimation { spring: 4; damping: 0.4 } }

Text {
 text: model.index
 }

MouseArea {
 anchors.fill: parent
 onClicked: {
 if (!ListView.isCurrentItem)
 view.currentIndex = index;
 else
 view.currentIndex = –1;
 }
 }
 }
 }
}