+ /**
+ * @brief Query the flick speed factor of the layout while swipping.
+ *
+ * This factor is used by the layout to customise its scroll speed while swiping.
+ * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
+ * and the layout position of the actors in ItemView will be moved by this result.
+ * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
+ * position of actors will be moved by 1.
+ * Therefore, the bigger the factor is, the faster the flick speed will be.
+ *
+ * @return The scroll speed factor of the layout.
+ */
+ virtual float GetFlickSpeedFactor() const;
+