如何在Flutter中找到Stack小部件树的高度？

import 'package:flutter/widgets.dart';

Widget build(BuildContext context) {
  return LayoutBuilder(
    builder: (BuildContext context, BoxConstraints constraints) {
      return Stack(
        children: [
          // 子部件
        ],
      );
    },
  );
}

Widget build(BuildContext context) {
  return LayoutBuilder(
    builder: (BuildContext context, BoxConstraints constraints) {
      double stackHeight = constraints.maxHeight; // 获取Stack的高度
      double stackWidth = constraints.maxWidth; // 获取Stack的宽度

      return Stack(
        children: [
          // 子部件
        ],
      );
    },
  );
}