PointerSignalResolver class

Mediates disputes over which listener should handle pointer signal events when multiple listeners wish to handle those events.

Pointer signals (such as PointerScrollEvent) are immediate, so unlike events that participate in the gesture arena, pointer signals always resolve at the end of event dispatch. Yet if objects interested in handling these signal events were to handle them directly, it would cause issues such as multiple Scrollable widgets in the widget hierarchy responding to the same mouse wheel event. Using this class, these events will only be dispatched to the first registered handler, which will in turn correspond to the widget that's deepest in the widget hierarchy.

To use this class, objects should register their event handler like so:

void handleSignalEvent(PointerSignalEvent event) {
  GestureBinding.instance.pointerSignalResolver.register(event, (PointerSignalEvent event) {
    // handle the event...
  });
}