handleEvent method

Implementation

@override
void handleEvent(PointerEvent event) {
  assert(_state != _DragState.ready);
  if (!event.synthesized
      && (event is PointerDownEvent || event is PointerMoveEvent)) {
    final VelocityTracker tracker = _velocityTrackers[event.pointer];
    assert(tracker != null);
    tracker.addPosition(event.timeStamp, event.position);
  }

  if (event is PointerMoveEvent) {
    final Offset delta = event.delta;
    if (_state == _DragState.accepted) {
      if (onUpdate != null) {
        invokeCallback<void>('onUpdate', () => onUpdate(DragUpdateDetails(
          sourceTimeStamp: event.timeStamp,
          delta: _getDeltaForDetails(delta),
          primaryDelta: _getPrimaryValueFromOffset(delta),
          globalPosition: event.position,
        )));
      }
    } else {
      _pendingDragOffset += delta;
      _lastPendingEventTimestamp = event.timeStamp;
      if (_hasSufficientPendingDragDeltaToAccept)
        resolve(GestureDisposition.accepted);
    }
  }
  stopTrackingIfPointerNoLongerDown(event);
}