Add a PathView.onPath property to help deal with unrequested items.

2 files changed, 66 insertions, 15 deletions

diff --git a/src/declarative/graphicsitems/qmlgraphicspathview.cpp b/src/declarative/graphicsitems/qmlgraphicspathview.cpp
index 112eda2..85e87eb 100644
--- a/src/declarative/graphicsitems/qmlgraphicspathview.cpp
+++ b/src/declarative/graphicsitems/qmlgraphicspathview.cpp
@@ -71,9 +71,11 @@ inline qreal qmlMod(qreal x, qreal y)
 class QmlGraphicsPathViewAttached : public QObject
 {
     Q_OBJECT
+
+    Q_PROPERTY(bool onPath READ isOnPath NOTIFY onPathChanged)
 public:
     QmlGraphicsPathViewAttached(QObject *parent)
-    : QObject(parent), mo(new QmlOpenMetaObject(this))
+    : QObject(parent), mo(new QmlOpenMetaObject(this)), onPath(false)
     {
     }
 
@@ -91,10 +93,49 @@ public:
         mo->setValue(name, val);
     }
 
+    bool isOnPath() const { return onPath; }
+    void setOnPath(bool on) {
+        if (on != onPath) {
+            onPath = on;
+            emit onPathChanged();
+        }
+    }
+
+Q_SIGNALS:
+    void onPathChanged();
+
 private:
     QmlOpenMetaObject *mo;
+    bool onPath;
 };
 
+
+QmlGraphicsItem *QmlGraphicsPathViewPrivate::getItem(int modelIndex)
+{
+    Q_Q(QmlGraphicsPathView);
+    requestedIndex = modelIndex;
+    QmlGraphicsItem *item = model->item(modelIndex);
+    if (item) {
+        if (QObject *obj = QmlGraphicsPathView::qmlAttachedProperties(item))
+            static_cast<QmlGraphicsPathViewAttached *>(obj)->setOnPath(true);
+        item->setParentItem(q);
+    }
+    requestedIndex = -1;
+    return item;
+}
+
+void QmlGraphicsPathViewPrivate::releaseItem(QmlGraphicsItem *item)
+{
+    if (!item || !model)
+        return;
+    if (QObject *obj = QmlGraphicsPathView::qmlAttachedProperties(item))
+        static_cast<QmlGraphicsPathViewAttached *>(obj)->setOnPath(false);
+    if (model->release(item) == 0) {
+        if (QObject *obj = QmlGraphicsPathView::qmlAttachedProperties(item))
+            static_cast<QmlGraphicsPathViewAttached *>(obj)->setOnPath(false);
+    }
+}
+
 /*!
     \qmlclass PathView QmlGraphicsPathView
     \brief The PathView element lays out model-provided items on a path.
@@ -126,6 +167,26 @@ QmlGraphicsPathView::~QmlGraphicsPathView()
 }
 
 /*!
+    \qmlattachedproperty bool PathView::onPath
+    This attached property holds whether the item is currently on the path.
+
+    If a pathItemCount has been set, it is possible that some items may
+    be instantiated, but not considered to be currently on the path.
+    Usually, these items would be set invisible, for example:
+
+    \code
+    Component {
+        Rectangle {
+            visible: PathView.onPath
+            ...
+        }
+    }
+    \endcode
+
+    It is attached to each instance of the delegate.
+*/
+
+/*!
     \qmlproperty model PathView::model
     This property holds the model providing data for the view.
 
diff --git a/src/declarative/graphicsitems/qmlgraphicspathview_p_p.h b/src/declarative/graphicsitems/qmlgraphicspathview_p_p.h
index 7ffe6ac..18cb205 100644
--- a/src/declarative/graphicsitems/qmlgraphicspathview_p_p.h
+++ b/src/declarative/graphicsitems/qmlgraphicspathview_p_p.h
@@ -79,7 +79,7 @@ public:
       : path(0), currentIndex(0), startPc(0), lastDist(0)
         , lastElapsed(0), stealMouse(false), ownModel(false), activeItem(0)
         , snapPos(0), dragMargin(0), moveOffset(this, &QmlGraphicsPathViewPrivate::setOffset)
-        , firstIndex(0), pathItems(-1), pathOffset(0), requestedIndex(-1), model(0)
+        , firstIndex(0), pathItems(-1), pathOffset(0), requestedIndex(-1)
         , moveReason(Other)
     {
         fixupOffsetEvent = QmlTimeLineEvent::timeLineEvent<QmlGraphicsPathViewPrivate, &QmlGraphicsPathViewPrivate::fixOffset>(&moveOffset, this);
@@ -95,18 +95,8 @@ public:
         q->connect(&tl, SIGNAL(updated()), q, SLOT(ticked()));
     }
 
-    QmlGraphicsItem *getItem(int modelIndex) {
-        Q_Q(QmlGraphicsPathView);
-        requestedIndex = modelIndex;
-        QmlGraphicsItem *item = model->item(modelIndex);
-        if (item)
-            item->setParentItem(q);
-        requestedIndex = -1;
-        return item;
-    }
-    void releaseItem(QmlGraphicsItem *item) {
-        model->release(item);
-    }
+    QmlGraphicsItem *getItem(int modelIndex);
+    void releaseItem(QmlGraphicsItem *item);
 
     bool isValid() const {
         return model && model->count() > 0 && model->isValid() && path;
@@ -143,7 +133,7 @@ public:
     int pathOffset;
     int requestedIndex;
     QList<QmlGraphicsItem *> items;
-    QmlGraphicsVisualModel *model;
+    QGuard<QmlGraphicsVisualModel> model;
     QVariant modelVariant;
     enum MovementReason { Other, Key, Mouse };
     MovementReason moveReason;