Displaced items were moving unnecessarily

They should only move if they actually change from the last set
position, and not if they are simply changing from their current item
position, as that is wrong during an animation.

This also cleans up some code for resetting the transition data.

Task-number: QTBUG-24586
Change-Id: I0a6635903975ebc40d5cf8398b943a9de92d4493
Reviewed-by: Martin Jones <martin.jones@nokia.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicklistview/data/multipleDisplaced.qml b/tests/auto/quick/qquicklistview/data/multipleDisplaced.qml
new file mode 100644
index 0000000000..e315270360
--- /dev/null
+++ b/tests/auto/quick/qquicklistview/data/multipleDisplaced.qml
@@ -0,0 +1,78 @@
+import QtQuick 2.0
+
+Rectangle {
+    id: root
+    width: 500
+    height: 600
+
+    property int duration: 10
+    property int count: list.count
+
+    Component {
+        id: myDelegate
+        Rectangle {
+            id: wrapper
+
+            property string nameData: name
+
+            objectName: "wrapper"
+            height: 20
+            width: 240
+            Text { text: index }
+            Text {
+                x: 30
+                id: textName
+                objectName: "textName"
+                text: name
+            }
+            Text {
+                x: 200
+                text: wrapper.y
+            }
+            color: ListView.isCurrentItem ? "lightsteelblue" : "white"
+        }
+    }
+
+    ListView {
+        id: list
+
+        property var displaceTransitionsStarted: new Object()
+        property bool displaceTransitionsDone: false
+
+        objectName: "list"
+        focus: true
+        anchors.centerIn: parent
+        width: 240
+        height: 320
+        model: testModel
+        delegate: myDelegate
+
+        displaced: Transition {
+            id: transition
+            SequentialAnimation {
+                ScriptAction {
+                    script: {
+                        var name = transition.ViewTransition.item.nameData
+                        if (list.displaceTransitionsStarted[name] == undefined)
+                            list.displaceTransitionsStarted[name] = 0
+                        list.displaceTransitionsStarted[name] += 1
+                    }
+                }
+                NumberAnimation {
+                    properties: "x,y"
+                    duration: root.duration
+                    easing.type: Easing.OutBounce
+                    easing.amplitude: 10.0      // longer-lasting bounce to trigger bug
+                }
+                PropertyAction { target: list; property: "displaceTransitionsDone"; value: true }
+            }
+        }
+    }
+
+    Rectangle {
+        anchors.fill: list
+        color: "lightsteelblue"
+        opacity: 0.2
+    }
+}
+