Biometric authentication has become a popular and secure way to verify the identity of users in mobile applications. Flutter, Google's UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase, provides excellent support for implementing biometric authentication. In this article, we will explore how to integrate biometric authentication into a Flutter app using the `local_auth` package.
Before we dive into the implementation, make sure you have Flutter installed on your machine. Create a new Flutter project using the following command:
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flutter create biometric_auth_demo cd biometric_auth_demo |
Now, open the `pubspec.yaml` file and add the `local_auth` package:
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dependencies: flutter: sdk: flutter local_auth: ^2.0.1 |
Run `flutter pub get` to fetch and install the dependencies.
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import 'package:flutter/material.dart'; import 'package:local_auth/local_auth.dart'; |
2. Create a `LocalAuthentication` instance: Create an instance of `LocalAuthentication` to interact with the biometric authentication services:
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final LocalAuthentication _localAuthentication = LocalAuthentication(); |
3. Check for Biometric Support: Before attempting to authenticate, check if the device supports biometric authentication:
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Future<void> checkBiometric() async { bool canCheckBiometrics = await _localAuthentication.canCheckBiometrics; print('Biometrics supported: $canCheckBiometrics'); } |
4. Retrieve Available Biometrics: You can also retrieve the types of biometrics available on the device:
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Future<void> getAvailableBiometrics() async { List<BiometricType> availableBiometrics = await _localAuthentication.getAvailableBiometrics(); print('Available biometrics: $availableBiometrics'); } |
5. Authenticate with Biometrics: Now, let's implement the biometric authentication:
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Future<void> authenticate() async { bool isAuthenticated = false; try { isAuthenticated = await _localAuthentication.authenticate( localizedReason: 'Authenticate to access the app', biometricOnly: true, useErrorDialogs: true, stickyAuth: true, ); } catch (e) { print('Error during biometric authentication: $e'); } if (isAuthenticated) { print('Biometric authentication successful'); } else { print('Biometric authentication failed'); } } |
6. UI Integration: Create a simple UI to trigger biometric authentication:
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void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( home: Scaffold( appBar: AppBar( title: Text('Biometric Auth Demo'), ), body: Center( child: ElevatedButton( onPressed: () async { await checkBiometric(); await getAvailableBiometrics(); await authenticate(); }, child: Text('Authenticate with Biometrics'), ), ), ), ); } } |
We explored how to integrate biometric authentication into a Flutter app using the `local_auth` package. By following the steps outlined above, you can enhance the security of your Flutter applications while providing a seamless and user-friendly authentication experience. Remember to handle errors appropriately and customize the authentication flow to meet the specific requirements of your app.
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