Flutter建议提供者插件suggestion_providers的使用

SuggestionProvider 是一个在 Flutter 中用于提供建议（如自动完成、搜索建议等）的插件或模式。虽然 Flutter 官方并没有直接提供名为 SuggestionProvider 的插件，但你可以通过自定义实现或使用现有的插件来实现类似的功能。

1. 自定义 SuggestionProvider

你可以通过自定义一个 SuggestionProvider 类来提供建议。以下是一个简单的示例：

import 'package:flutter/material.dart';

class SuggestionProvider with ChangeNotifier {
  List<String> _suggestions = [];
  List<String> get suggestions => _suggestions;

  void updateSuggestions(String query) {
    // 这里可以根据查询条件更新建议列表
    _suggestions = _generateSuggestions(query);
    notifyListeners();
  }

  List<String> _generateSuggestions(String query) {
    // 这里是一个简单的示例，根据查询生成建议
    List<String> allSuggestions = [
      "Apple",
      "Banana",
      "Cherry",
      "Date",
      "Elderberry",
      "Fig",
      "Grape",
      "Honeydew"
    ];

    return allSuggestions
        .where((suggestion) => suggestion.toLowerCase().startsWith(query.toLowerCase()))
        .toList();
  }
}

2. 在 UI 中使用 SuggestionProvider

你可以在 UI 中使用 ChangeNotifierProvider 或 Provider 来提供 SuggestionProvider 的实例，并在 UI 中监听建议的变化。

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

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (context) => SuggestionProvider(),
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Suggestion Provider Example')),
        body: SuggestionWidget(),
      ),
    );
  }
}

class SuggestionWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final suggestionProvider = Provider.of<SuggestionProvider>(context);

    return Column(
      children: [
        TextField(
          decoration: InputDecoration(
            labelText: 'Search',
          ),
          onChanged: (value) {
            suggestionProvider.updateSuggestions(value);
          },
        ),
        Expanded(
          child: ListView.builder(
            itemCount: suggestionProvider.suggestions.length,
            itemBuilder: (context, index) {
              return ListTile(
                title: Text(suggestionProvider.suggestions[index]),
              );
            },
          ),
        ),
      ],
    );
  }
}

3. 使用现有的插件

如果你不想自己实现，可以使用一些现有的 Flutter 插件来实现自动完成或搜索建议功能，例如：

• flutter_typeahead: 这个插件提供了一个强大的自动完成功能，支持从本地或远程数据源获取建议。

  dependencies:
    flutter_typeahead: ^4.1.0
  

  使用示例：

  import 'package:flutter/material.dart';
  import 'package:flutter_typeahead/flutter_typeahead.dart';
  
  void main() {
    runApp(MyApp());
  }
  
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        home: Scaffold(
          appBar: AppBar(title: Text('Flutter TypeAhead Example')),
          body: TypeAheadExample(),
        ),
      );
    }
  }
  
  class TypeAheadExample extends StatelessWidget {
    final List<String> suggestions = [
      "Apple",
      "Banana",
      "Cherry",
      "Date",
      "Elderberry",
      "Fig",
      "Grape",
      "Honeydew"
    ];
  
    @override
    Widget build(BuildContext context) {
      return Padding(
        padding: const EdgeInsets.all(16.0),
        child: TypeAheadField<String>(
          textFieldConfiguration: TextFieldConfiguration(
            decoration: InputDecoration(
              labelText: 'Search',
            ),
          ),
          suggestionsCallback: (pattern) {
            return suggestions
                .where((suggestion) => suggestion.toLowerCase().startsWith(pattern.toLowerCase()))
                .toList();
          },
          itemBuilder: (context, suggestion) {
            return ListTile(
              title: Text(suggestion),
            );
          },
          onSuggestionSelected: (suggestion) {
            print("Selected: $suggestion");
          },
        ),
      );
    }
  }