功能整合

dart

class ChatPage extends StatelessWidget {
 const ChatPage({super.key});
​
 @override
 Widget build(BuildContext context) => Scaffold(
       appBar: AppBar(title: const Text(App.title)),
       body: LlmChatView(
         welcomeMessage: 'Hello and welcome to the Flutter AI Toolkit!',
         provider: FirebaseProvider(
          model: FirebaseAI.geminiAI().generativeModel(
             model: 'gemini-2.5-flash',
           ),
         ),
       ),
     );
}

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dart

class ChatPage extends StatelessWidget {
 const ChatPage({super.key});
​
 @override
 Widget build(BuildContext context) => Scaffold(
       appBar: AppBar(title: const Text(App.title)),
       body: LlmChatView(
         suggestions: [
           'I\'m a Star Wars fan. What should I wear for Halloween?',
           'I\'m allergic to peanuts. What candy should I avoid at Halloween?',
           'What\'s the difference between a pumpkin and a squash?',
         ],
         provider: FirebaseProvider(
          model: FirebaseAI.geminiAI().generativeModel(
             model: 'gemini-2.5-flash',
           ),
         ),
       ),
     );
}

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dart

class _HomePageState extends State<HomePage> {
  ...
  // create a new provider with the given history and the current settings
  LlmProvider _createProvider([List<ChatMessage>? history]) => FirebaseProvider(
      history: history,
        ...,
        model: FirebaseAI.geminiAI().generativeModel(
          model: 'gemini-2.5-flash',
          ...,
          systemInstruction: Content.system('''
You are a helpful assistant that generates recipes based on the ingredients and
instructions provided as well as my food preferences, which are as follows:
${Settings.foodPreferences.isEmpty ? 'I don\'t have any food preferences' : Settings.foodPreferences}
​
You should keep things casual and friendly. You may generate multiple recipes in a single response, but only if asked. ...
''',
          ),
        ),
      );
  ...
}

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dart

class _HomePageState extends State<HomePage> {
  ...
  void _onSettingsSave() => setState(() {
        // move the history over from the old provider to the new one
        final history = _provider.history.toList();
        _provider = _createProvider(history);
      });
}

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dart

class ChatPage extends StatelessWidget {
  const ChatPage({super.key});
​
  @override
  Widget build(BuildContext context) {
    // ...
​
    return Scaffold(
      appBar: AppBar(title: const Text('Restricted Chat')),
      body: LlmChatView(
        // ...
        enableAttachments: false,
        enableVoiceNotes: false,
      ),
    );
  }
}

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dart

LlmChatView(
  // ...
  speechToText: MyCustomSpeechToText(),
)

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dart

class ChatPage extends StatelessWidget {
  // ...
​
  void _onCancel(BuildContext context) {
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(const SnackBar(content: Text('Chat cancelled')));
  }
​
  @override
  Widget build(BuildContext context) => Scaffold(
    appBar: AppBar(title: const Text(App.title)),
    body: LlmChatView(
      // ...
      onCancelCallback: _onCancel,
      cancelMessage: 'Request cancelled',
    ),
  );
}

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dart

abstract class LlmProvider implements Listenable {
  Stream<String> generateStream(
    String prompt, {
    Iterable<Attachment> attachments,
  });
​
  Stream<String> sendMessageStream(
    String prompt, {
    Iterable<Attachment> attachments,
  });
​
  Iterable<ChatMessage> get history;
  set history(Iterable<ChatMessage> history);
}

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dart

void _clearHistory() => _provider.history = [];

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dart

class _HomePageState extends State<HomePage> {
  ...
  void _onSettingsSave() => setState(() {
        // move the history over from the old provider to the new one
        final history = _provider.history.toList();
        _provider = _createProvider(history);
      });
}

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dart

class _HomePageState extends State<HomePage> {
  ...
  // create a new provider with the given history and the current settings
  LlmProvider _createProvider([List<ChatMessage>? history]) =>
    FirebaseProvider(
      history: history,
      ...
    );
  ...
}

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dart

Future<void> _saveHistory() async {
  // get the latest history
  final history = _provider.history.toList();
​
  // write the new messages
  for (var i = 0; i != history.length; ++i) {
    // skip if the file already exists
    final file = await _messageFile(i);
    if (file.existsSync()) continue;
​
    // write the new message to disk
    final map = history[i].toJson();
    final json = JsonEncoder.withIndent('  ').convert(map);
    await file.writeAsString(json);
  }
}

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dart

Future<void> _loadHistory() async {
  // read the history from disk
  final history = <ChatMessage>[];
  for (var i = 0;; ++i) {
    final file = await _messageFile(i);
    if (!file.existsSync()) break;
​
    final map = jsonDecode(await file.readAsString());
    history.add(ChatMessage.fromJson(map));
  }
​
  // set the history on the controller
  _provider.history = history;
}

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dart

LlmChatView(
  provider: _provider,
  welcomeMessage: _welcomeMessage,
  responseBuilder: (context, response) => RecipeResponseView(
    response,
  ),
),

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dart

class RecipeResponseView extends StatelessWidget {
  const RecipeResponseView(this.response, {super.key});
  final String response;
​
  @override
  Widget build(BuildContext context) {
    final children = <Widget>[];
    String? finalText;
​
    // created with the response from the LLM as the response streams in, so
    // many not be a complete response yet
    try {
      final map = jsonDecode(response);
      final recipesWithText = map['recipes'] as List<dynamic>;
      finalText = map['text'] as String?;
​
      for (final recipeWithText in recipesWithText) {
        // extract the text before the recipe
        final text = recipeWithText['text'] as String?;
        if (text != null && text.isNotEmpty) {
          children.add(MarkdownBody(data: text));
        }
​
        // extract the recipe
        final json = recipeWithText['recipe'] as Map<String, dynamic>;
        final recipe = Recipe.fromJson(json);
        children.add(const Gap(16));
        children.add(Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(recipe.title, style: Theme.of(context).textTheme.titleLarge),
            Text(recipe.description),
            RecipeContentView(recipe: recipe),
          ],
        ));
​
        // add a button to add the recipe to the list
        children.add(const Gap(16));
        children.add(OutlinedButton(
          onPressed: () => RecipeRepository.addNewRecipe(recipe),
          child: const Text('Add Recipe'),
        ));
        children.add(const Gap(16));
      }
    } catch (e) {
      debugPrint('Error parsing response: $e');
    }
​
    ...
​
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: children,
    );
  }
}

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dart

class _HomePageState extends State<HomePage> {
  ...
​
  // create a new provider with the given history and the current settings
  LlmProvider _createProvider([List<ChatMessage>? history]) => FirebaseProvider(
        ...
        model: FirebaseAI.geminiAI().generativeModel(
          ...
          generationConfig: GenerationConfig(
            responseMimeType: 'application/json',
            responseSchema: Schema(...),
          systemInstruction: Content.system('''
...
Generate each response in JSON format
with the following schema, including one or more "text" and "recipe" pairs as
well as any trailing text commentary you care to provide:
​
{
  "recipes": [
    {
      "text": "Any commentary you care to provide about the recipe.",
      "recipe":
      {
        "title": "Recipe Title",
        "description": "Recipe Description",
        "ingredients": ["Ingredient 1", "Ingredient 2", "Ingredient 3"],
        "instructions": ["Instruction 1", "Instruction 2", "Instruction 3"]
      }
    }
  ],
  "text": "any final commentary you care to provide",
}
''',
          ),
        ),
      );
  ...
}

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dart

LlmChatView(
  provider: FirebaseProvider(...),
  style: LlmChatViewStyle(...),
),

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dart

class _EditRecipePageState extends State<EditRecipePage> {
  ...
  final _provider = FirebaseProvider(...);
  ...
  Future<void> _onMagic() async {
    final stream = _provider.sendMessageStream(
      'Generate a modified version of this recipe based on my food preferences: '
      '${_ingredientsController.text}\n\n${_instructionsController.text}',
    );
    var response = await stream.join();
    final json = jsonDecode(response);
​
    try {
      final modifications = json['modifications'];
      final recipe = Recipe.fromJson(json['recipe']);
​
      if (!context.mounted) return;
      final accept = await showDialog<bool>(
        context: context,
        builder: (context) => AlertDialog(
          title: Text(recipe.title),
          content: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const Text('Modifications:'),
              const Gap(16),
              Text(_wrapText(modifications)),
            ],
          ),
          actions: [
            TextButton(
              onPressed: () => context.pop(true),
              child: const Text('Accept'),
            ),
            TextButton(
              onPressed: () => context.pop(false),
              child: const Text('Reject'),
            ),
          ],
        ),
      );
      ...
    } catch (ex) {
      ...
      }
    }
  }
}

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dart

class ChatPage extends StatelessWidget {
  final _provider = FirebaseProvider(...);
​
  @override
  Widget build(BuildContext context) => Scaffold(
      appBar: AppBar(title: const Text(App.title)),
      body: LlmChatView(
        provider: _provider,
        messageSender: _logMessage,
      ),
    );
​
  Stream<String> _logMessage(
    String prompt, {
    required Iterable<Attachment> attachments,
  }) async* {
    // log the message and attachments
    debugPrint('# Sending Message');
    debugPrint('## Prompt\n$prompt');
    debugPrint('## Attachments\n${attachments.map((a) => a.toString())}');
​
    // forward the message on to the provider
    final response = _provider.sendMessageStream(
      prompt,
      attachments: attachments,
    );
​
    // log the response
    final text = await response.join();
    debugPrint('## Response\n$text');
​
    // return it
    yield text;
  }
}

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