+ /**
+ * Indicates when a view item is being hovered over.
+ * @param item The item that is being hovered over, or @c nullptr
+ * if no view item is being hovered over.
+ * @remarks the default implementation does nothing.
+ */
+ virtual void item_hover(const shared_ptr<ViewItem> &item);
+
+ /**
+ * Indicates the event an a view item has been clicked.
+ * @param item the view item that has been clicked.
+ * @remarks the default implementation does nothing.
+ */
+ virtual void item_clicked(const shared_ptr<ViewItem> &item);
+
+ /**
+ * Returns true if the selection of row items allows dragging.
+ * @return Returns true if the drag is acceptable.
+ */
+ bool accept_drag() const;
+
+ /**
+ * Returns true if the mouse button is down.
+ */
+ bool mouse_down() const;
+
+ /**
+ * Drag the dragging items by the delta offset.
+ * @param delta the drag offset in pixels.
+ */
+ void drag_items(const QPoint &delta);
+
+ /**
+ * Sets this item into the dragged state.
+ */
+ virtual void drag();
+
+ /**
+ * Drag the background by the delta offset.
+ * @param delta the drag offset in pixels.
+ * @remarks The default implementation does nothing.
+ */
+ virtual void drag_by(const QPoint &delta);
+
+ /**
+ * Sets this item into the un-dragged state.
+ */
+ virtual void drag_release();
+
+ /**
+ * Gets the items in the view widget.
+ */
+ virtual vector< shared_ptr<ViewItem> > items() = 0;
+
+ /**
+ * Gets the first view item which has a hit-box that contains @c pt .
+ * @param pt the point to search with.
+ * @return the view item that has been found, or and empty
+ * @c shared_ptr if no item was found.
+ */
+ virtual shared_ptr<ViewItem> get_mouse_over_item(const QPoint &pt) = 0;
+
+ /**
+ * Handles left mouse button press events.
+ * @param event the mouse event that triggered this handler.
+ */
+ void mouse_left_press_event(QMouseEvent *event);
+
+ /**
+ * Handles left mouse button release events.
+ * @param event the mouse event that triggered this handler.
+ */
+ void mouse_left_release_event(QMouseEvent *event);
+
+ /**
+ * Handles touch begin update and end events.
+ * @param e the event that triggered this handler.
+ */
+ virtual bool touch_event(QTouchEvent *event);
+
+protected:
+ bool event(QEvent *event);
+
+ void mousePressEvent(QMouseEvent *event);
+ void mouseReleaseEvent(QMouseEvent *event);
+ void mouseMoveEvent(QMouseEvent *event);
+
+ void leaveEvent(QEvent *event);
+
+public Q_SLOTS:
+ void clear_selection();
+
+Q_SIGNALS:
+ void selection_changed();
+