handleThumbPressEnd method

Implementation

@protected
@mustCallSuper
void handleThumbPressEnd(Offset localPosition, Velocity velocity) {
  assert(_debugCheckHasValidScrollPosition());
  final Axis? direction = getScrollbarDirection();
  if (direction == null) {
    return;
  }
  _maybeStartFadeoutTimer();
  _cachedController = null;
  _lastDragUpdateOffset = null;

  // _thumbDrag might be null if the drag activity ended and called _disposeThumbDrag.
  assert(_thumbHold == null || _thumbDrag == null);
  if (_thumbDrag == null) {
    return;
  }

  // On mobile platforms flinging the scrollbar thumb causes a ballistic
  // scroll, just like it does via a touch drag. Likewise for desktops when
  // dragging on the trackpad or with a stylus.
  final TargetPlatform platform = ScrollConfiguration.of(context).getPlatform(context);
  final Velocity adjustedVelocity = switch (platform) {
    TargetPlatform.iOS || TargetPlatform.android => -velocity,
    _ => Velocity.zero,
  };
  final RenderBox renderBox = _scrollbarPainterKey.currentContext!.findRenderObject()! as RenderBox;
  final DragEndDetails details = DragEndDetails(
    localPosition: localPosition,
    globalPosition: renderBox.localToGlobal(localPosition),
    velocity: adjustedVelocity,
    primaryVelocity: switch (direction) {
      Axis.horizontal => adjustedVelocity.pixelsPerSecond.dx,
      Axis.vertical => adjustedVelocity.pixelsPerSecond.dy,
    },
  );

  _thumbDrag?.end(details);
  assert(_thumbDrag == null);

  _startDragScrollbarAxisOffset = null;
  _lastDragUpdateOffset = null;
  _startDragThumbOffset = null;
  _cachedController = null;
}