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Flutter Fingerprint Authentication

In this post we are going to learn how to perform Local Authentication in the Flutter Application

For this example we are going to use TouchID or FingerPrint authentication method

Let's get start
Step 1: Add local_auth plugin in pubspec.yaml file

dependencies:
local_auth: ^0.6.1

Step 2: Create a dart file and add below code

import 'package:flutter/material.dart';
import 'package:local_auth/local_auth.dart';
import 'package:flutter/services.dart';


class TouchID extends StatefulWidget {
  @override
  _TouchIDState createState() => _TouchIDState();
}

class _TouchIDState extends State<TouchID> {
  final LocalAuthentication localAuth = LocalAuthentication();
  bool _canCheckBiometric = false;
  String _authorizeText = 'Not Authorized!';

  List<BiometricType> availableBiometrics = List<BiometricType>();

  Future<void> _authorize() async {
    bool _isAuthorized = false;
    try {
      _isAuthorized = await localAuth.authenticateWithBiometrics(
        localizedReason: 'Please authenticate to Complete this process',
        useErrorDialogs: true,
        stickyAuth: true,
      );
    } on PlatformException catch (e) {
      print(e);
    }

    if (!mounted) return;

    setState(() {
      if (_isAuthorized) {
        _authorizeText = "Authorized Successfully!";
      } else {
        _authorizeText = "Not Authorized!";
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Touch ID Auth Example')),
      body: Center(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Padding(
                padding: const EdgeInsets.all(8.0),
                child: Text(_authorizeText,style: TextStyle(color: Colors.black38,fontSize: 20),),
              ),
              RaisedButton(
                child: Text('Authorize',style: TextStyle(color: Colors.white,fontSize: 20),),
                color: Colors.pink,
                onPressed: _authorize,
              )
            ],
          )),
    );
  }
}

Step 3: Update MainActivity

class MainActivity: FlutterFragmentActivity() {
    override fun configureFlutterEngine( flutterEngine: FlutterEngine) {
        GeneratedPluginRegistrant.registerWith(flutterEngine);
    }
}

Step 4: Call Authenticate dart file in Main

void main() => runApp(MyApp());

class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      theme: ThemeData(
        primaryColor: Colors.pink
      ),
      home: TouchID(),
    );
  }

}

Step 5: Let's run application

Flutter Fingerprint Authentication