使用ChangeNotifier + Provider的SearchDelegate

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

class SearchModel extends ChangeNotifier {
  String keyword = '';

  void updateKeyword(String newKeyword) {
    keyword = newKeyword;
    notifyListeners();
  }
}

class SearchPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final searchModel = Provider.of<SearchModel>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text('Search'),
      ),
      body: Column(
        children: [
          TextField(
            onChanged: (value) => searchModel.updateKeyword(value),
          ),
          SizedBox(height: 16),
          Text('Search keyword: ${searchModel.keyword}'),
          SizedBox(height: 16),
          // Display search results here
        ],
      ),
    );
  }
}

class CustomSearchDelegate extends SearchDelegate<String> {
  @override
  List<Widget> buildActions(BuildContext context) {
    return [
      IconButton(
        icon: Icon(Icons.clear),
        onPressed: () {
          query = '';
        },
      ),
    ];
  }

  @override
  Widget buildLeading(BuildContext context) {
    return IconButton(
      icon: Icon(Icons.arrow_back),
      onPressed: () {
        close(context, '');
      },
    );
  }

  @override
  Widget buildResults(BuildContext context) {
    final searchModel = Provider.of<SearchModel>(context);

    // Perform search based on query and display results
    // ...

    return Container();
  }

  @override
  Widget buildSuggestions(BuildContext context) {
    final searchModel = Provider.of<SearchModel>(context);

    // Display suggestions based on query
    // ...

    return Container();
  }
}

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (context) => SearchModel(),
      child: MaterialApp(
        home: SearchPage(),
      ),
    ),
  );
}