gemini_nano_android 0.1.0

A Flutter plugin to access on-device Gemini Nano models via Android AI Core. Enables offline inference and privacy-first text generation.

example/lib/main.dart

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

import 'package:flutter/services.dart';
import 'package:gemini_nano_android/gemini_nano_android.dart';

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

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _modelVersion = 'Unknown';
  bool? _isAvailable;
  List<String> _generatedResults = [];
  double? _executionTime;
  bool _isGenerating = false;
  final _promptController = TextEditingController();
  final _geminiNanoAndroidPlugin = GeminiNanoAndroid();

  // Configuration parameters
  double? _temperature;
  final _seedController = TextEditingController();
  final _topKController = TextEditingController();
  final _candidateCountController = TextEditingController();
  final _maxOutputTokensController = TextEditingController();

  @override
  void initState() {
    super.initState();
    initPlatformState();
  }

  @override
  void dispose() {
    _promptController.dispose();
    _seedController.dispose();
    _topKController.dispose();
    _candidateCountController.dispose();
    _maxOutputTokensController.dispose();
    super.dispose();
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> initPlatformState() async {
    String modelVersion;
    bool? isAvailable;
    // Platform messages may fail, so we use a try/catch PlatformException.
    // We also handle the message potentially returning null.
    try {
      modelVersion =
          await _geminiNanoAndroidPlugin.getModelVersion() ??
          'Unknown model version';
    } on PlatformException {
      modelVersion = 'Failed to get model version.';
    }

    try {
      isAvailable = await _geminiNanoAndroidPlugin.isAvailable();
    } on PlatformException {
      isAvailable = false;
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      _modelVersion = modelVersion;
      _isAvailable = isAvailable;
    });
  }

  Future<void> _generateText() async {
    if (_promptController.text.isEmpty) return;

    setState(() {
      _executionTime = null;
      _isGenerating = true;
      _generatedResults = [];
    });

    final stopwatch = Stopwatch()..start();

    try {
      final result = await _geminiNanoAndroidPlugin.generate(
        prompt: _promptController.text,
        temperature: _temperature,
        seed: int.tryParse(_seedController.text),
        topK: int.tryParse(_topKController.text),
        candidateCount: int.tryParse(_candidateCountController.text),
        maxOutputTokens: int.tryParse(_maxOutputTokensController.text),
      );
      stopwatch.stop();
      if (!mounted) return;
      setState(() {
        _generatedResults = result;
        _executionTime = stopwatch.elapsedMilliseconds / 1000.0;
        _isGenerating = false;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _generatedResults = ['Error: $e'];
        _executionTime = null;
        _isGenerating = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: const Text('Gemini Nano Example')),
        body: SafeArea(
          child: Padding(
            padding: const EdgeInsets.all(16.0),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.start,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              spacing: 16,
              children: [
                Expanded(
                  child: SingleChildScrollView(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.stretch,
                      spacing: 16,
                      children: [
                        Text('Model version: $_modelVersion'),
                        Text.rich(
                          TextSpan(
                            text: 'Gemini Nano Available: ',
                            style: const TextStyle(fontWeight: FontWeight.bold),
                            children: [
                              TextSpan(
                                text: _isAvailable == true
                                    ? 'AVAILABLE'
                                    : 'UNAVAILABLE',
                                style: TextStyle(
                                  color: _isAvailable == true
                                      ? Colors.green
                                      : Colors.red,
                                ),
                              ),
                            ],
                          ),
                        ),
                        TextField(
                          controller: _promptController,
                          decoration: const InputDecoration(
                            labelText: 'Enter prompt',
                            border: OutlineInputBorder(),
                          ),
                          maxLines: 4,
                        ),
                        ExpansionTile(
                          title: const Text('Advanced Settings'),
                          shape: const Border(),
                          collapsedShape: const Border(),
                          children: [
                            Padding(
                              padding: const EdgeInsets.symmetric(
                                horizontal: 16.0,
                              ),
                              child: Column(
                                spacing: 16,
                                children: [
                                  Row(
                                    children: [
                                      const Text('Temperature: '),
                                      Expanded(
                                        child: Slider(
                                          value: _temperature ?? 0.5,
                                          min: 0.0,
                                          max: 1.0,
                                          divisions: 10,
                                          label: (_temperature ?? 0.5)
                                              .toString(),
                                          onChanged: _isGenerating
                                              ? null
                                              : (value) {
                                                  setState(() {
                                                    _temperature = value;
                                                  });
                                                },
                                        ),
                                      ),
                                      Text(
                                        (_temperature ?? 0.5).toStringAsFixed(
                                          1,
                                        ),
                                      ),
                                    ],
                                  ),
                                  Row(
                                    spacing: 16,
                                    children: [
                                      Expanded(
                                        child: TextField(
                                          controller: _seedController,
                                          enabled: !_isGenerating,
                                          decoration: const InputDecoration(
                                            labelText: 'Seed (Optional)',
                                            hintText: 'Enter integer seed',
                                            border: OutlineInputBorder(),
                                          ),
                                          keyboardType: TextInputType.number,
                                        ),
                                      ),
                                      Expanded(
                                        child: TextField(
                                          controller: _topKController,
                                          enabled: !_isGenerating,
                                          decoration: const InputDecoration(
                                            labelText: 'Top K (Optional)',
                                            hintText: 'Enter integer Top K',
                                            border: OutlineInputBorder(),
                                          ),
                                          keyboardType: TextInputType.number,
                                        ),
                                      ),
                                    ],
                                  ),
                                  Row(
                                    spacing: 16,
                                    children: [
                                      Expanded(
                                        child: TextField(
                                          controller: _candidateCountController,
                                          enabled: !_isGenerating,
                                          decoration: const InputDecoration(
                                            labelText:
                                                'Candidate Count (Optional)',
                                            hintText: 'Enter integer',
                                            border: OutlineInputBorder(),
                                          ),
                                          keyboardType: TextInputType.number,
                                        ),
                                      ),
                                      Expanded(
                                        child: TextField(
                                          controller:
                                              _maxOutputTokensController,
                                          enabled: !_isGenerating,
                                          decoration: const InputDecoration(
                                            labelText:
                                                'Max Output Tokens (Optional)',
                                            hintText: 'Enter integer',
                                            border: OutlineInputBorder(),
                                          ),
                                          keyboardType: TextInputType.number,
                                        ),
                                      ),
                                    ],
                                  ),
                                ],
                              ),
                            ),
                          ],
                        ),
                        ElevatedButton(
                          onPressed: _isAvailable == true && !_isGenerating
                              ? _generateText
                              : null,
                          child: Text(
                            _isGenerating ? 'Generating...' : 'Generate',
                          ),
                        ),
                        if (_executionTime != null) ...[
                          Text(
                            'Execution time: ${_executionTime!.toStringAsFixed(2)}s',
                            style: const TextStyle(fontWeight: FontWeight.bold),
                          ),
                        ],
                        if (_generatedResults.isNotEmpty && !_isGenerating) ...[
                          const Text(
                            'GENERATED RESULTS',
                            style: TextStyle(fontWeight: FontWeight.bold),
                            textAlign: TextAlign.center,
                          ),
                          ..._generatedResults.asMap().entries.map((entry) {
                            return Card(
                              child: Padding(
                                padding: const EdgeInsets.all(8.0),
                                child: Column(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    if (_generatedResults.length > 1)
                                      Text(
                                        'Candidate ${entry.key + 1}:',
                                        style: const TextStyle(
                                          fontWeight: FontWeight.bold,
                                          color: Colors.grey,
                                        ),
                                      ),
                                    Text(entry.value),
                                  ],
                                ),
                              ),
                            );
                          }),
                        ],
                      ],
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}