Example Flutter code to build a ChatBot using google_generative_ai package.

main.dart

// Import necessary packages
import 'package:flutter/material.dart';
import 'package:google_generative_ai/google_generative_ai.dart';

// Replace with your actual API key
const apiKey = 'YOUR_API_KEY';

// Main app widget
class MyChatApp extends StatefulWidget {
  @override
  _MyChatAppState createState() => _MyChatAppState();
}

class _MyChatAppState extends State<MyChatApp> {
  final TextEditingController textController = TextEditingController();

  List<String> messages = []; // Stores chat history

  bool isGenerating = false;

  void sendMessage(String text) async {
    setState(() => isGenerating = true);
    // Create GenerativeModel instance
    final model = GenerativeModel(model: 'gemini-pro', apiKey: apiKey);

    // Prepare request content
    final content = [Content.text(text)];

    // Generate response
    final response = await model.generateContent(content);

    print("response $response");

    print("text ${response.text}");

    // Add messages to chat history
    setState(() {
      messages.add(response.text!);
      isGenerating = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Chatbot')),
        body: Column(
          children: [
            // Chat history display
            Expanded(
              child: ListView.builder(
                itemCount: messages.length,
                itemBuilder: (context, index) {
                  return Text(messages[index]);
                },
              ),
            ),
            isGenerating == true
                ? Center(child: CircularProgressIndicator())
                : Container(),
            // User input field
            Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: textController,
                    onSubmitted: (text) => sendMessage(text),
                  ),
                ),
                IconButton(
                  icon: Icon(Icons.send),
                  onPressed: () {
                    sendMessage(textController.text);

                    setState(() {
                      messages.add(textController.text);
                    });

                    textController.clear();
                  }, // Get text from field
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}