如何修改SliverAppbar小部件以获得以下布局/将TextInputField searchBar集成到SliverAppbar中

import 'package:flutter/material.dart';

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            expandedHeight: 200, // 设置AppBar展开的高度
            flexibleSpace: FlexibleSpaceBar(
              title: Text('My App'), // 设置AppBar标题
              background: Image.asset(
                'assets/images/header_image.jpg', // 设置AppBar背景图片
                fit: BoxFit.cover,
              ),
            ),
            floating: true, // 设置AppBar是否浮动
            pinned: true, // 设置AppBar是否固定
            snap: false, // 设置AppBar是否自动展开/收起
            // 添加搜索框
            actions: <Widget>[
              IconButton(
                icon: Icon(Icons.search),
                onPressed: () {
                  // 在这里处理搜索框点击事件
                },
              ),
            ],
          ),
          // 添加其他Sliver部件
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (BuildContext context, int index) {
                return ListTile(
                  title: Text('Item $index'),
                );
              },
              childCount: 20,
            ),
          ),
        ],
      ),
    );
  }
}

void main() {
  runApp(MyApp());
}