I have the following issue: Scrolling with inertia, initiated by a ScrollGesture, stops after a while in a ListView.
The reason for this is the following: the javadoc for ScrollEvent has this: The event is delivered to the top-most node picked on the gesture coordinates in time of the gesture start - the whole gesture is delivered to the same node even if the coordinates change during the gesture. Looking into the code, this is indeed what happens: when a SCROLL_STARTED is received, the targetNode is picked, and this is then used as the first one in the dispatchchain for the remainder of the scroll event (even after SCROLL_FINISHED occurred). But the inertia scrolling causes new SCROLL events to be generated after the SCROLL_FINISHED, and it will cause the ListView to scroll its items. The initially selected cell might be reclaimed (or its contents are not shown in the ListTile anymore, as this is re-used for other content). In that case, the dispatch chain is broken, as the targetNode.getParent() will return null, and the scroll event is never passed to the ListView. There are a number of potentials solutions to this problem. Re-calculating the pickedTarget on every SCROLL event seems not a good solution to me (what are the pick coordinates after the touchpoint has been released? It will slow down performance as well). Rather, it would be better if somehow the pickedTarget for these events is the ListView itself, and not one of its cells. We can already do this by setting the ListCell and its content to mouseTransparent, but that will make them unavailable for mouseClick events as well. So it seems to me we need something like "gestureTransparent", by which we can indicate a Node not to be interested in handling gestures. The code for picking the target Node currently ignores the Node if it has the mouseTransparent set. I would propose to add a gestureTransparent property on Node, and to add the following check: if we need to find the pickedTarget for a gestureEvent, it should never return a node with gestureTransparent set to true. This would require a change in Scene.ScenePeerListener.scrollEvent() where the ScrollEvent is created, and where the pickTarget is computed by pick(x,y) which only ignores mouseTransparent nodes at the moment. Should I file an issue for this? - Johan
