参数类型SearchBar不能赋值给flutter中的参数类型Widget

import 'package:flutter/material.dart';

class SearchBar extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      // SearchBar的样式和布局
      child: Row(
        children: [
          Expanded(
            child: TextField(
              // 输入框的样式和属性
              decoration: InputDecoration(
                hintText: 'Search',
              ),
            ),
          ),
          IconButton(
            icon: Icon(Icons.search),
            onPressed: () {
              // 点击搜索按钮的操作
            },
          ),
        ],
      ),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'My App',
      home: Scaffold(
        appBar: AppBar(
          title: Text('Search Bar Demo'),
        ),
        body: Container(
          padding: EdgeInsets.all(16.0),
          child: Column(
            children: [
              SearchBar(), // 使用SearchBar
              // 其他Widget
            ],
          ),
        ),
      ),
    );
  }
}

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