import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: LayoutBuilder(
          builder: (BuildContext context, BoxConstraints constraints) {
            return Stack(
              children: <Widget>[
                // 你的子组件
                Container(color: Colors.blue),
                Positioned.fill(
                  child: Align(
                    alignment: Alignment.center,
                    child: Text('半屏高度的Stack'),
                  ),
                ),
              ],
              // 设置高度为屏幕高度的一半
              alignment: Alignment.center,
              clipBehavior: Clip.none,
            );
          },
        ),
      ),
    );
  }
}

Stack(
  children: [
    // 你的内容
  ],
).constrained(
  constraints: BoxConstraints(
    maxHeight: MediaQuery.of(context).size.height / 2,
  ),
)

import React from 'react';
import { View, Dimensions } from 'react-native';

const HalfScreenStack = () => {
  const screenHeight = Dimensions.get('window').height;
  
  return (
    <View style={{ height: screenHeight / 2, position: 'relative' }}>
      {/* 你的子组件 */}
      <View style={{ position: 'absolute', top: 0, left: 0, right: 0, bottom: 0 }}>
        {/* 内容 */}
      </View>
    </View>
  );
};

export default HalfScreenStack;

<div class="half-screen-stack">
  <div class="stack-item">内容1</div>
  <div class="stack-item">内容2</div>
</div>

<style>
  .half-screen-stack {
    position: relative;
    height: 50vh; /* 使用视口高度单位 */
    width: 100%;
  }
  
  .stack-item {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }
</style>

val displayMetrics = DisplayMetrics()
windowManager.defaultDisplay.getMetrics(displayMetrics)
val screenHeight = displayMetrics.heightPixels

val stackLayout = FrameLayout(context).apply {
    layoutParams = FrameLayout.LayoutParams(
        FrameLayout.LayoutParams.MATCH_PARENT,
        screenHeight / 2
    )
}

// 添加子视图
stackLayout.addView(childView1)
stackLayout.addView(childView2)