showBy method

@override void showBy(Widget widget, ContextGetter contextGetter)

showBy基本都show菜单等，所以暂时不提供返回值

Implementation

@override
void showBy(Widget widget, ContextGetter contextGetter) {
  final RenderBox assigner = contextGetter.context.findRenderObject()! as RenderBox;
  final RenderBox overlay = context.findRenderObject()! as RenderBox;
  var size = assigner.size;
  var parentSize = overlay.size;
  var leftTop = assigner.localToGlobal(Offset.zero, ancestor: overlay);
  double? left;
  double? top;
  double? bottom;
  double? right;
  if (leftTop.dx + size.width / 2 > parentSize.width / 2) {
    right = parentSize.width - (leftTop.dx + size.width);
  } else {
    left = leftTop.dx;
  }
  if (leftTop.dy + size.height / 2 > parentSize.height / 2) {
    bottom = parentSize.height - leftTop.dy;
  } else {
    top = leftTop.dy + size.height;
  }
  var background = GestureDetector(
    behavior: HitTestBehavior.opaque,
    onTap: () {
      removeWidget(widget);
    },
    child: const SizedBox.expand(),
  );
  showWidget(widget, background: background, top: top, left: left, bottom: bottom, right: right, level: 1);
  // childMap[widget] = [widget, background];
}