Biometric Authorization

A Flutter plugin that provides easy-to-use biometric authentication for both Android and iOS platforms. This plugin allows your app to securely authenticate users using biometric features such as fingerprint, face recognition, and other available biometric methods.

Features

Check if biometric authentication is available on the device
Verify if biometric credentials are enrolled
Get a list of available biometric types (fingerprint, face recognition.)
Authenticate users with biometric verification
Support for both default system UI and custom UI for authentication
Platform-specific implementations for Android and iOS

Screenshots

iOS Authentication

Touch ID - System UI	Touch ID - Custom UI	Face ID - Custom UI

Android Authentication

Default UI	Custom UI (Sheet)	Custom UI (Dialog)

Platform Support

Android	iOS
Fingerprint, Face recognition	Face ID, Touch ID
API 21+	iOS 11.0+

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  biometric_authorization: ^0.1.0

Then run:

flutter pub get

Android Setup

Add the following permission to your AndroidManifest.xml file:

<uses-permission android:name="android.permission.USE_BIOMETRIC" />

Important: You must use FlutterFragmentActivity instead of FlutterActivity in your Android project. In your MainActivity.kt file:

import io.flutter.embedding.android.FlutterFragmentActivity

class MainActivity: FlutterFragmentActivity() {
    // ...
}

iOS Setup

Add the following to your Info.plist file:

<key>NSFaceIDUsageDescription</key>
<string>Your app needs to authenticate using your biometric data for secure access</string>

Usage

Import the package:

import 'package:biometric_authorization/biometric_authorization.dart';
import 'package:biometric_authorization/biometric_type.dart';

Check Biometric Availability

final biometricAuth = BiometricAuthorization();

// Check if biometric authentication is available
bool isAvailable = await biometricAuth.isBiometricAvailable();

// Check if biometric credentials are enrolled
bool isEnrolled = await biometricAuth.isBiometricEnrolled();

// Get available biometric types
List<BiometricType> types = await biometricAuth.getAvailableBiometricTypes();

Authenticate with Biometrics

Using Default System UI

try {
  bool authenticated = await biometricAuth.authenticate(
    reason: 'Please authenticate to access your account',
    title: 'Biometric Authentication',
    confirmText: 'Verify',
  );

  if (authenticated) {
    // User authenticated successfully
    print('Authentication successful');
  } else {
    // Authentication failed or was cancelled
    print('Authentication failed');
  }
} catch (e) {
  print('Error during authentication: $e');
}

Using Custom UI

bool authenticated = await biometricAuth.authenticate(
  reason: 'Please authenticate to access your account',
  title: 'Biometric Authentication',
  confirmText: 'Verify',
  useCustomUI: true,
);

Using Dialog UI (Available in Android)

bool authenticated = await biometricAuth.authenticate(
  reason: 'Please authenticate to access your account',
  title: 'Biometric Authentication',
  confirmText: 'Verify',
  useDialog: true
);

Platform-Specific Parameters

The authenticate method has some parameters that behave differently depending on the platform:

biometricType: This parameter is required on iOS to specify which biometric method to use (face or fingerprint). On Android, it's optional as Android will automatically use available methods.
```
// Example for iOS - must specify biometricType
await biometricAuth.authenticate(
  biometricType: BiometricType.face, // Use Face ID
  reason: 'Authenticate to continue',
);
```
cancelText: This parameter is only effective on Android. It specifies the text for the cancel button in the authentication dialog. On iOS, this parameter is ignored.
```
// Example for Android - can specify cancelText
await biometricAuth.authenticate(
  reason: 'Authenticate to continue',
  cancelText: 'Not now',
);
```

API Reference

BiometricAuthorization

Main class providing biometric authentication functionality.

Methods

Future<bool> isBiometricAvailable() - Checks if biometric authentication is available on the device.
Future<bool> isBiometricEnrolled() - Checks if biometric credentials are enrolled on the device.
Future<List<BiometricType>> getAvailableBiometricTypes() - Gets available biometric types on the device.
Future<bool> authenticate({...}) - Authenticates the user with biometrics.

BiometricType

Enum representing different biometric authentication types:

BiometricType.face - Face recognition (Face ID on iOS, face authentication on Android)
BiometricType.fingerprint - Fingerprint recognition (Touch ID on iOS, fingerprint on Android)
BiometricType.none - No biometric type available

Platform-Specific Features

Android

Support for both fingerprint and face recognition
Custom UI option with bottom sheet design
Support for predictive back gesture navigation on Android 13+
Handles biometric lockout scenarios gracefully
Requires FlutterFragmentActivity instead of FlutterActivity
The cancelText parameter can be used to customize the cancel button text

iOS

Native support for Face ID and Touch ID
Seamless integration with Apple's security framework
Proper handling of authentication cancelation and errors
The biometricType parameter is required to specify which biometric method to use

Example

A full example app is available in the example directory.

Contributing

Contributions are welcome! If you find a bug or want a feature, please open an issue or submit a PR.

License

This project is licensed under the MIT License - see the LICENSE file for details.