Secure App Lock #

A Flutter package that provides secure app lock functionality with PIN code and biometric authentication support. This package allows you to easily add app-level security to your Flutter applications by requiring users to authenticate when the app comes back from the background.

Features #

• PIN Code Authentication: Set up a 4-digit PIN code for app access
• Biometric Authentication: Support for fingerprint, face recognition, and other biometric methods
• Automatic Locking: Automatically locks the app when it goes to background
• Lifecycle Management: Handles app lifecycle states to trigger authentication
• Secure Storage: Uses Flutter Secure Storage to securely store PIN codes and settings
• Customizable UI: Provides default PIN entry screen with option to use custom lock screens

Getting started #

Add this package to your pubspec.yaml:

dependencies:
  secure_app_lock: ^1.0.0

Then run:

flutter pub get

Platform Setup #

Android

Add the following permissions to your android/app/src/main/AndroidManifest.xml:

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

iOS

Add the following to your ios/Runner/Info.plist:

<key>NSFaceIDUsageDescription</key>
<string>This app uses Face ID for secure authentication</string>

Usage #

Basic Setup #

1. Wrap your main app with AppLockLifecycleWatcher:

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

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

class MyApp extends StatelessWidget {
  final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      navigatorKey: navigatorKey,
      home: AppLockLifecycleWatcher(
        navigatorKey: navigatorKey,
        child: HomePage(),
      ),
    );
  }
}

Managing App Lock #

import 'package:secure_app_lock/secure_app_lock.dart';

class SettingsPage extends StatelessWidget {
  final lockController = SecureLock.lockController;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Security Settings')),
      body: Column(
        children: [
          // Enable/Disable app lock
          ListenableBuilder(
            listenable: lockController,
            builder: (context, child) {
              return SwitchListTile(
                title: Text('App Lock'),
                value: lockController.enabled,
                onChanged: (value) {
                  if (value) {
                    // Navigate to PIN setup
                    Navigator.push(
                      context,
                      MaterialPageRoute(
                        builder: (context) => PinCodePage(),
                      ),
                    );
                  } else {
                    lockController.disable();
                  }
                },
              );
            },
          ),
          
          // Biometrics toggle
          ListenableBuilder(
            listenable: lockController,
            builder: (context, child) {
              return SwitchListTile(
                title: Text('Biometric Authentication'),
                value: lockController.biometricsEnabled,
                onChanged: lockController.enabled 
                  ? (value) => lockController.toggleBiometrics()
                  : null,
              );
            },
          ),
        ],
      ),
    );
  }
}

Custom Lock Screen #

You can provide your own custom lock screen:

AppLockLifecycleWatcher(
  navigatorKey: navigatorKey,
  lockScreen: CustomLockScreen(), // Your custom widget
  child: HomePage(),
)

Manual Authentication #

// Check if biometric authentication is available and authenticate
bool success = await SecureLock.lockController.tryBiometricUnlock();

// Manually lock the app
SecureLock.lockController.lock();

// Manually unlock the app
SecureLock.lockController.unlock();

API Reference #

SecureLock #

Main entry point for accessing the app lock controller.

static final AppLockController lockController = AppLockController();

AppLockController #

Controls the app lock state and provides authentication methods.

Properties:

• bool locked - Whether the app is currently locked
• bool enabled - Whether app lock is enabled
• bool biometricsEnabled - Whether biometric authentication is enabled
• String? pin - Current PIN code (encrypted)

Methods:

• setPin(String pin) - Set a new PIN code
• lock() - Lock the app
• unlock() - Unlock the app
• enable() - Enable app lock
• disable() - Disable app lock
• toggleBiometrics() - Toggle biometric authentication
• tryBiometricUnlock() - Attempt biometric authentication

AppLockLifecycleWatcher #

Widget that monitors app lifecycle and triggers authentication when needed.

PinCodePage #

Default PIN code entry screen with setup and authentication modes.

Additional information #

This package uses the following dependencies:

• flutter_secure_storage for secure data storage
• local_auth for biometric authentication

Contributing #

Contributions are welcome! Please feel free to submit a Pull Request.

Issues #

Please file issues on the GitHub repository.

License #

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