Ensure ListView contentHeight is set to a valid size.

If the view height is 0 no items will be created so the contentHeight
can not be estimated.  The currentItem is usually created,
so it is possible to use that to estimate.

Task-number: QTBUG-16037
Reviewed-by: Bea Lam

3 files changed, 63 insertions, 0 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativelistview.cpp b/src/declarative/graphicsitems/qdeclarativelistview.cpp
index d008f91..2a7f508 100644
--- a/src/declarative/graphicsitems/qdeclarativelistview.cpp
+++ b/src/declarative/graphicsitems/qdeclarativelistview.cpp
@@ -265,6 +265,8 @@ public:
                 }
             }
             pos = (*(--visibleItems.constEnd()))->endPosition() + invisibleCount * (averageSize + spacing);
+        } else if (model && model->count()) {
+            pos = model->count() * averageSize + (model->count()-1) * spacing;
         }
         return pos;
     }
@@ -1050,6 +1052,8 @@ void QDeclarativeListViewPrivate::updateCurrent(int modelIndex)
         // This is slightly sub-optimal, but section heading caching minimizes the impact.
         if (currentItem->section)
             currentItem->section->setVisible(false);
+        if (visibleItems.isEmpty())
+            averageSize = currentItem->size();
     }
     updateHighlight();
     emit q->currentIndexChanged();
@@ -1576,6 +1580,7 @@ void QDeclarativeListView::setModel(const QVariant &model)
                     d->updateTrackedItem();
                 }
             }
+            d->updateViewport();
         }
         connect(d->model, SIGNAL(itemsInserted(int,int)), this, SLOT(itemsInserted(int,int)));
         connect(d->model, SIGNAL(itemsRemoved(int,int)), this, SLOT(itemsRemoved(int,int)));
@@ -1647,6 +1652,7 @@ void QDeclarativeListView::setDelegate(QDeclarativeComponent *delegate)
                     d->highlight->setPosition(d->currentItem->position());
                 d->updateTrackedItem();
             }
+            d->updateViewport();
         }
     }
     emit delegateChanged();
diff --git a/tests/auto/declarative/qdeclarativelistview/data/qtbug16037.qml b/tests/auto/declarative/qdeclarativelistview/data/qtbug16037.qml
new file mode 100644
index 0000000..0756618
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativelistview/data/qtbug16037.qml
@@ -0,0 +1,37 @@
+import QtQuick 1.0
+
+Item {
+    width: 640
+    height: 480
+
+    function setModel() {
+        listView.model = listModel1
+    }
+
+    ListModel {
+        id: listModel1
+        ListElement { text: "Apple" }
+        ListElement { text: "Banana" }
+        ListElement { text: "Orange" }
+        ListElement { text: "Coconut" }
+    }
+
+    Rectangle {
+        width: 200
+        height: listView.contentHeight
+        color: "yellow"
+        anchors.centerIn: parent
+
+        ListView {
+            id: listView
+            objectName: "listview"
+            anchors.fill: parent
+
+            delegate: Item {
+                width: 200
+                height: 20
+                Text { text: model.text; anchors.centerIn: parent }
+            }
+        }
+    }
+}
diff --git a/tests/auto/declarative/qdeclarativelistview/tst_qdeclarativelistview.cpp b/tests/auto/declarative/qdeclarativelistview/tst_qdeclarativelistview.cpp
index ff90d32..b834d46 100644
--- a/tests/auto/declarative/qdeclarativelistview/tst_qdeclarativelistview.cpp
+++ b/tests/auto/declarative/qdeclarativelistview/tst_qdeclarativelistview.cpp
@@ -104,6 +104,7 @@ private slots:
     void sizeLessThan1();
     void QTBUG_14821();
     void resizeDelegate();
+    void QTBUG_16037();
 
 private:
     template <class T> void items();
@@ -1944,6 +1945,25 @@ void tst_QDeclarativeListView::resizeDelegate()
     delete canvas;
 }
 
+void tst_QDeclarativeListView::QTBUG_16037()
+{
+    QDeclarativeView *canvas = createView();
+
+    canvas->setSource(QUrl::fromLocalFile(SRCDIR "/data/qtbug16037.qml"));
+    qApp->processEvents();
+
+    QDeclarativeListView *listview = findItem<QDeclarativeListView>(canvas->rootObject(), "listview");
+    QTRY_VERIFY(listview != 0);
+
+    QVERIFY(listview->contentHeight() <= 0.0);
+
+    QMetaObject::invokeMethod(canvas->rootObject(), "setModel");
+
+    QTRY_COMPARE(listview->contentHeight(), 80.0);
+
+    delete canvas;
+}
+
 void tst_QDeclarativeListView::qListModelInterface_items()
 {
     items<TestModel>();