Implement functionality to ensure that the current item is always visible. Needs testing.

8 files changed, 80 insertions, 72 deletions

diff --git a/src/qgraphicslistview.cpp b/src/qgraphicslistview.cpp
index 169db3e..5f10627 100644
--- a/src/qgraphicslistview.cpp
+++ b/src/qgraphicslistview.cpp
@@ -1154,69 +1154,40 @@ int QtGraphicsListView::firstIndex() const
 }
 
 /*!
-  Sets the offset to ensure that the item represented
-  by the given \a index is visible in the view.
-  Note that this function is potentially slow.
-
-  \sa setOffset()
+  Returns an offset value that will ensure that the given \a index
+  is visible in the view.
  */
-void QtGraphicsListView::setOffsetToEnsureIndexIsVisible(int index)
+qreal QtGraphicsListView::offsetToEnsureIndexIsVisible(int index) const
 {
-    Q_D(QtGraphicsListView);
+    Q_D(const QtGraphicsListView);
     const QRectF item = itemGeometry(index); // potentially slow
     const QRectF view = geometry();
-    if (!view.contains(item)) {
-        if (orientation() == Qt::Vertical) {
-            if (item.top() < view.top())
-                setOffset(d->offset + item.top());
-            else if (item.bottom() > view.bottom())
-                setOffset(d->offset + item.bottom() - view.height());
-        } else {
-            if (item.left() < view.left())
-                setOffset(d->offset + item.x());
-            else if (item.right() > view.right())
-                setOffset(d->offset + item.right() - view.width());
-        }
+    if (orientation() == Qt::Vertical) {
+        if (item.bottom() < view.top())
+            return d->offset + item.top();
+        else if (item.top() > view.bottom())
+            return d->offset + item.bottom() - view.height();
+    } else {
+        if (item.right() < view.left())
+            return d->offset + item.x();
+        else if (item.left() > view.right())
+            return d->offset + item.right() - view.width();
     }
+    return d->offset;
 }
 
 /*!
+  Returns an first index value that will ensure that the given \a index
+  is visible in the view.
  */
-void QtGraphicsListView::setFirstIndexToEnsureIndexIsVisible(int index)
+int QtGraphicsListView::firstIndexToEnsureIndexIsVisible(int index) const
 {
-    // ### this breaks views with a different layout
-#if 0
-    Q_D(QtGraphicsListView);
-    // ### cache
-    if (index > d->firstIndex) {
-        const QSizeF constraint = (d->orientation == Qt::Horizontal
-                                   ? QSizeF(-1, size().height())
-                                   : QSizeF(size().width(), -1));
-        QStyleOptionViewItemV4 option;
-        initStyleOption(&option);
-        if (orientation() == Qt::Vertical) {
-            qreal height = size().height() + d->offset;
-            for (; index >= 0; --index) {
-                initStyleOption(&option, index);
-                height -= d->itemSizeHint(&option, index, constraint).height();
-                if (height < 0)
-                    break;
-            }
-        } else {
-            qreal width = size().width() + d->offset;
-            for (; index >= 0; --index) {
-                initStyleOption(&option, index);
-                width -= d->itemSizeHint(&option, index, constraint).width();
-                if (width < 0)
-                    break;
-            }
-        }
-    }
-    if (index > -1)
-        setFirstIndex(index);
-#else
-    Q_UNUSED(index);
-#endif
+    Q_D(const QtGraphicsListView);
+    if (index < d->firstIndex)
+        return index;
+    else if (index >= (d->firstIndex + d->items.count()))
+        return qBound(0, index - d->items.count() + 1, maximumFirstIndex()); // slow
+    return d->firstIndex;
 }
 
 /*!
diff --git a/src/qgraphicslistview.h b/src/qgraphicslistview.h
index bbca758..17829c6 100644
--- a/src/qgraphicslistview.h
+++ b/src/qgraphicslistview.h
@@ -146,11 +146,12 @@ public:
 
     QGraphicsObject *itemForIndex(int index) const;
 
+    qreal offsetToEnsureIndexIsVisible(int index) const;
+    int firstIndexToEnsureIndexIsVisible(int index) const;
+
 public Q_SLOTS:
     void setFirstIndex(int index);
     void setOffset(qreal offset);
-    void setOffsetToEnsureIndexIsVisible(int index);
-    void setFirstIndexToEnsureIndexIsVisible(int index);
     void updateLayout();
 
 Q_SIGNALS:
diff --git a/src/qlistcontroller.cpp b/src/qlistcontroller.cpp
index f1dbd9e..27bcd7c 100644
--- a/src/qlistcontroller.cpp
+++ b/src/qlistcontroller.cpp
@@ -105,6 +105,21 @@ void QtListControllerPrivate::_q_offsetChanged(qreal offset)
 }
 
 /*!
+  \internal
+ */
+void QtListControllerPrivate::_q_currentChanged(int current, int previous)
+{
+    Q_UNUSED(previous);
+    if (!view || !model)
+        return;
+    // ensure current is visible
+    if (scrollPerItem)
+        view->setFirstIndex(view->firstIndexToEnsureIndexIsVisible(current));
+    else
+        view->setOffset(view->offsetToEnsureIndexIsVisible(current));
+}
+
+/*!
  \internal
 */
 void QtListControllerPrivate::_q_animationFinished()
@@ -164,6 +179,11 @@ void QtListControllerPrivate::animateFirstIndex(int index)
 */
 
 /*!
+    \enum SelectionBehavior
+    \brief controls how selection is done in the list
+*/
+
+/*!
     Constructs a list controller with the given \a parent.
 */
 QtListController::QtListController(QObject *parent)
@@ -250,16 +270,18 @@ void QtListController::setSelectionManager(QtListSelectionManager *selectionMana
     Q_D(QtListController);
     if (d->selectionManager == selectionManager)
         return;
-    if (d->selectionManager)
+    if (d->selectionManager) {
         disconnect(d->selectionManager, SIGNAL(destroyed()), this, SLOT(_q_selectionsDestroyed()));
+        disconnect(d->selectionManager, SIGNAL(currentChanged(int,int)), this, SLOT(_q_currentChanged(int,int)));
+    }
 
     QtListSelectionManager *old = d->selectionManager;
-
     d->selectionManager = selectionManager;
 
     if (d->selectionManager) {
         d->selectionManager->setModel(d->model);
         connect(d->selectionManager, SIGNAL(destroyed()), this, SLOT(_q_selectionsDestroyed()));
+        connect(d->selectionManager, SIGNAL(currentChanged(int,int)), this, SLOT(_q_currentChanged(int,int)));
     }
 
     if (d->view)
@@ -382,11 +404,18 @@ void QtListController::setScrollValue(qreal value)
     Q_D(QtListController);
     if (!d->view)
         return;
-    if (d->scrollPerItem)
-        //d->animateFirstIndex(value);
-        d->view->setFirstIndex(static_cast<int>(value));
-    else
+    if (d->scrollPerItem) {
+        int index = static_cast<int>(value);
+        if (d->view->firstIndex() == index)
+            return;
+        //d->animateFirstIndex(index);
+        d->view->setFirstIndex(index);
+    } else {
+        if (d->view->offset() == value)
+            return;
         d->view->setOffset(value);
+    }
+    emit scrollValueChanged(value);
 }
 
 /*!
@@ -516,7 +545,7 @@ bool QtListController::keyPressEvent(QKeyEvent *event)
                         return true;
                 }
             } else { // no modifier
-                //d->selectionManager->endAnchoredSelection();
+                d->selectionManager->endAnchoredSelection();
                 d->selectionManager->clearSelections();
                 d->selectionManager->setCurrentItem(index);
                 switch (d->behavior) {
diff --git a/src/qlistcontroller.h b/src/qlistcontroller.h
index 889efef..aea8664 100644
--- a/src/qlistcontroller.h
+++ b/src/qlistcontroller.h
@@ -131,8 +131,9 @@ private:
     Q_PRIVATE_SLOT(d_func(), void _q_modelDestroyed())
     Q_PRIVATE_SLOT(d_func(), void _q_viewDestroyed())
     Q_PRIVATE_SLOT(d_func(), void _q_selectionsDestroyed())
-    Q_PRIVATE_SLOT(d_func(), void _q_firstIndexChanged(int index))
-    Q_PRIVATE_SLOT(d_func(), void _q_offsetChanged(qreal offset))
+    Q_PRIVATE_SLOT(d_func(), void _q_firstIndexChanged(int))
+    Q_PRIVATE_SLOT(d_func(), void _q_offsetChanged(qreal))
+    Q_PRIVATE_SLOT(d_func(), void _q_currentChanged(int,int))
     Q_PRIVATE_SLOT(d_func(), void _q_animationFinished())
 };
 
diff --git a/src/qlistcontroller_p.h b/src/qlistcontroller_p.h
index 80c8990..a58b0f6 100644
--- a/src/qlistcontroller_p.h
+++ b/src/qlistcontroller_p.h
@@ -58,6 +58,7 @@ public:
     void _q_selectionsDestroyed();
     void _q_firstIndexChanged(int index);
     void _q_offsetChanged(qreal offset);
+    void _q_currentChanged(int current, int previous);
     void _q_animationFinished();
 
     void animateFirstIndex(int index);
diff --git a/src/qlistwidgetng.cpp b/src/qlistwidgetng.cpp
index 1a70187..8ef2c6b 100644
--- a/src/qlistwidgetng.cpp
+++ b/src/qlistwidgetng.cpp
@@ -141,14 +141,8 @@ void QtListWidgetNGPrivate::_q_modelChanged(QtListModelInterface *current, QtLis
 
 void QtListWidgetNGPrivate::_q_selectionManagerChanged(QtListSelectionManager *current, QtListSelectionManager *previous)
 {
-    if (previous) {
-        QObject::disconnect(previous, SIGNAL(currentChanged(int,int)),
-                            controller->view(), SLOT(setFirstIndexToEnsureIndexIsVisible(int)));
-    }
-    if (current) {
-        QObject::connect(current, SIGNAL(currentChanged(int,int)),
-                         controller->view(), SLOT(setFirstIndexToEnsureIndexIsVisible(int)));
-    }
+    Q_UNUSED(current);
+    Q_UNUSED(previous);
 }
 
 void QtListWidgetNGPrivate::_q_viewChanged(QtGraphicsListView *current, QtGraphicsListView *previous)
@@ -156,15 +150,24 @@ void QtListWidgetNGPrivate::_q_viewChanged(QtGraphicsListView *current, QtGraphi
     Q_Q(QtListWidgetNG);
     if (previous) {
         q->scene()->removeItem(previous);
+        QObject::disconnect(previous, SIGNAL(firstIndexChanged(int)), q, SLOT(_q_firstIndexChanged(int)));
     }
     if (current) {
         q->scene()->addItem(current);
         q->scene()->setActiveWindow(current);
         current->grabKeyboard();
+        QObject::connect(current, SIGNAL(firstIndexChanged(int)), q, SLOT(_q_firstIndexChanged(int)));
     }
     //_q_updateGeometries();
 }
 
+void QtListWidgetNGPrivate::_q_firstIndexChanged(int index)
+{
+    Q_Q(QtListWidgetNG);
+    if (q->verticalScrollBar()->value() != index)
+        q->verticalScrollBar()->setValue(index);
+}
+
 void QtListWidgetNGPrivate::_q_updateGeometries()
 {
     Q_Q(QtListWidgetNG);
diff --git a/src/qlistwidgetng.h b/src/qlistwidgetng.h
index 5167992..eca1912 100644
--- a/src/qlistwidgetng.h
+++ b/src/qlistwidgetng.h
@@ -71,6 +71,7 @@ private:
     Q_PRIVATE_SLOT(d_func(), void _q_modelChanged(QtListModelInterface *current, QtListModelInterface *previous))
     Q_PRIVATE_SLOT(d_func(), void _q_selectionManagerChanged(QtListSelectionManager *current, QtListSelectionManager *previous))
     Q_PRIVATE_SLOT(d_func(), void _q_viewChanged(QtGraphicsListView *current, QtGraphicsListView *previous))
+    Q_PRIVATE_SLOT(d_func(), void _q_firstIndexChanged(int index))
 };
 
 QT_END_NAMESPACE
diff --git a/src/qlistwidgetng_p.h b/src/qlistwidgetng_p.h
index 294deb1..38ffd41 100644
--- a/src/qlistwidgetng_p.h
+++ b/src/qlistwidgetng_p.h
@@ -59,6 +59,7 @@ public:
     void _q_modelChanged(QtListModelInterface *current, QtListModelInterface *previous);
     void _q_selectionManagerChanged(QtListSelectionManager *current, QtListSelectionManager *previous);
     void _q_viewChanged(QtGraphicsListView *current, QtGraphicsListView *previous);
+    void _q_firstIndexChanged(int index);
     void _q_updateGeometries();
 
     void initialize();