PathView items were not correctly updated when rootIndex changed.

PathView got confused because it queried the model when removing
items due to the rootIndex change. This caused new items to be added
since the model->count() was not zero (it was the count for the new
rootIndex).  Calculate the PathView modelCount similarly to the other
views (rather than querying the model) and correctly handle the
modelCount being set to zero.

Change-Id: I9e4fb27c14aa8c77ad37ff01d95c123f909db20d
Task-number: QTBUG-16366
Reviewed-by: Bea Lam

3 files changed, 95 insertions, 16 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativepathview.cpp b/src/declarative/graphicsitems/qdeclarativepathview.cpp
index 050a9ca..269d3b7 100644
--- a/src/declarative/graphicsitems/qdeclarativepathview.cpp
+++ b/src/declarative/graphicsitems/qdeclarativepathview.cpp
@@ -1455,17 +1455,18 @@ void QDeclarativePathView::itemsInserted(int modelIndex, int count)
     if (!d->isValid() || !isComponentComplete())
         return;
 
-    d->itemCache += d->items;
-    d->items.clear();
-    if (modelIndex <= d->currentIndex) {
-        d->currentIndex += count;
-        emit currentIndexChanged();
-    } else if (d->offset != 0) {
-        d->offset += count;
-        d->offsetAdj += count;
+    if (d->modelCount) {
+        d->itemCache += d->items;
+        d->items.clear();
+        if (modelIndex <= d->currentIndex) {
+            d->currentIndex += count;
+            emit currentIndexChanged();
+        } else if (d->offset != 0) {
+            d->offset += count;
+            d->offsetAdj += count;
+        }
     }
-
-    d->modelCount = d->model->count();
+    d->modelCount += count;
     if (d->flicking || d->moving) {
         d->regenerate();
         d->updateCurrent();
@@ -1502,18 +1503,29 @@ void QDeclarativePathView::itemsRemoved(int modelIndex, int count)
     d->itemCache += d->items;
     d->items.clear();
 
+    bool changedOffset = false;
     if (modelIndex > d->currentIndex) {
         if (d->offset >= count) {
+            changedOffset = true;
             d->offset -= count;
             d->offsetAdj -= count;
         }
     }
 
-    d->modelCount = d->model->count();
-    d->regenerate();
-    d->updateCurrent();
-    if (!d->modelCount)
+    d->modelCount -= count;
+    if (!d->modelCount) {
+        while (d->itemCache.count())
+            d->releaseItem(d->itemCache.takeLast());
+        d->offset = 0;
+        changedOffset = true;
+        d->tl.reset(d->moveOffset);
         update();
+    } else {
+        d->regenerate();
+        d->updateCurrent();
+    }
+    if (changedOffset)
+        emit offsetChanged();
     if (currentChanged)
         emit currentIndexChanged();
     emit countChanged();
@@ -1601,7 +1613,7 @@ void QDeclarativePathView::movementEnding()
 int QDeclarativePathViewPrivate::calcCurrentIndex()
 {
     int current = -1;
-    if (model && items.count()) {
+    if (modelCount && model && items.count()) {
         offset = qmlMod(offset, modelCount);
         if (offset < 0)
             offset += modelCount;
@@ -1617,7 +1629,7 @@ void QDeclarativePathViewPrivate::updateCurrent()
     Q_Q(QDeclarativePathView);
     if (moveReason != Mouse)
         return;
-    if (!haveHighlightRange || highlightRangeMode != QDeclarativePathView::StrictlyEnforceRange)
+    if (!modelCount || !haveHighlightRange || highlightRangeMode != QDeclarativePathView::StrictlyEnforceRange)
         return;
 
     int idx = calcCurrentIndex();
diff --git a/tests/auto/declarative/qdeclarativepathview/data/treemodel.qml b/tests/auto/declarative/qdeclarativepathview/data/treemodel.qml
new file mode 100644
index 0000000..56f7ae4
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativepathview/data/treemodel.qml
@@ -0,0 +1,19 @@
+import QtQuick 1.0
+
+PathView {
+    width: 320
+    height: 240
+    function setRoot(index) {
+        vdm.rootIndex = vdm.modelIndex(index);
+    }
+    model: VisualDataModel {
+        id: vdm
+        model: myModel
+        delegate: Text { objectName: "wrapper"; text: display }
+    }
+
+    path: Path {
+        startX: 0; startY: 120
+        PathLine { x: 320; y: 120 }
+    }
+}
diff --git a/tests/auto/declarative/qdeclarativepathview/tst_qdeclarativepathview.cpp b/tests/auto/declarative/qdeclarativepathview/tst_qdeclarativepathview.cpp
index f39e4b9..ebb5f98 100644
--- a/tests/auto/declarative/qdeclarativepathview/tst_qdeclarativepathview.cpp
+++ b/tests/auto/declarative/qdeclarativepathview/tst_qdeclarativepathview.cpp
@@ -53,6 +53,7 @@
 #include <QtDeclarative/private/qdeclarativevaluetype_p.h>
 #include <QAbstractListModel>
 #include <QStringListModel>
+#include <QStandardItemModel>
 #include <QFile>
 
 #include "../../../shared/util.h"
@@ -62,6 +63,25 @@
 #define SRCDIR "."
 #endif
 
+static void initStandardTreeModel(QStandardItemModel *model)
+{
+    QStandardItem *item;
+    item = new QStandardItem(QLatin1String("Row 1 Item"));
+    model->insertRow(0, item);
+
+    item = new QStandardItem(QLatin1String("Row 2 Item"));
+    item->setCheckable(true);
+    model->insertRow(1, item);
+
+    QStandardItem *childItem = new QStandardItem(QLatin1String("Row 2 Child Item"));
+    item->setChild(0, childItem);
+
+    item = new QStandardItem(QLatin1String("Row 3 Item"));
+    item->setIcon(QIcon());
+    model->insertRow(2, item);
+}
+
+
 class tst_QDeclarativePathView : public QObject
 {
     Q_OBJECT
@@ -90,6 +110,7 @@ private slots:
     void visualDataModel();
     void undefinedPath();
     void mouseDrag();
+    void treeModel();
 
 private:
     QDeclarativeView *createView();
@@ -900,6 +921,33 @@ void tst_QDeclarativePathView::mouseDrag()
     delete canvas;
 }
 
+void tst_QDeclarativePathView::treeModel()
+{
+    QDeclarativeView *canvas = createView();
+
+    QStandardItemModel model;
+    initStandardTreeModel(&model);
+    canvas->engine()->rootContext()->setContextProperty("myModel", &model);
+
+    canvas->setSource(QUrl::fromLocalFile(SRCDIR "/data/treemodel.qml"));
+
+    QDeclarativePathView *pathview = qobject_cast<QDeclarativePathView*>(canvas->rootObject());
+    QVERIFY(pathview != 0);
+    QCOMPARE(pathview->count(), 3);
+
+    QDeclarativeText *item = findItem<QDeclarativeText>(pathview, "wrapper", 0);
+    QVERIFY(item);
+    QCOMPARE(item->text(), QLatin1String("Row 1 Item"));
+
+    QVERIFY(QMetaObject::invokeMethod(pathview, "setRoot", Q_ARG(QVariant, 1)));
+    QCOMPARE(pathview->count(), 1);
+
+    QTRY_VERIFY(item = findItem<QDeclarativeText>(pathview, "wrapper", 0));
+    QTRY_COMPARE(item->text(), QLatin1String("Row 2 Child Item"));
+
+    delete canvas;
+}
+
 QDeclarativeView *tst_QDeclarativePathView::createView()
 {
     QDeclarativeView *canvas = new QDeclarativeView(0);