Biometric authentication in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the package needed for biometric authentication in Flutter.

Flutter

import '[1]';

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Acupertino_icons/cupertino_icons.dart

Bflutter/material.dart

Cdart:async

Dlocal_auth/local_auth.dart

Attempts:

3 left

💡 Hint

Common Mistakes

Importing unrelated packages like material.dart or cupertino_icons.

Forgetting to import the biometric package.

The 'local_auth/local_auth.dart' package provides biometric authentication features in Flutter.

2fill in blank

medium

Complete the code to create an instance of the LocalAuthentication class.

Flutter

final LocalAuthentication auth = [1]();

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ABiometricAuth

BLocalAuthentication

CAuthLocal

DAuthenticationLocal

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect class names like BiometricAuth.

Confusing the class name with variable names.

The LocalAuthentication class is used to access biometric authentication methods.

3fill in blank

hard

Fix the error in the code to check if biometric authentication is available.

Flutter

bool canCheck = await auth.[1]();

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AcanCheckBiometrics

BisDeviceSupported

Cauthenticate

DcheckBiometrics

Attempts:

3 left

💡 Hint

Common Mistakes

Using authenticate() which starts the authentication process instead of checking availability.

Using isDeviceSupported() which checks device support but not biometric enrollment.

The method canCheckBiometrics() returns true if biometric hardware is available and enrolled.

4fill in blank

hard

Fill both blanks to start biometric authentication with a localized reason and options.

Flutter

bool authenticated = await auth.[1](
  localizedReason: '[2]',
  options: const AuthenticationOptions(
    stickyAuth: true,
  ),
);

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Aauthenticate

BauthenticateWithBiometrics

CstartAuthentication

DPlease authenticate to proceed

Attempts:

3 left

💡 Hint

Common Mistakes

Using deprecated or incorrect method names.

Not providing a clear localizedReason string.

The authenticate() method starts the biometric prompt with a reason shown to the user.

5fill in blank

hard

Fill all three blanks to handle authentication failure and success with messages.

Flutter

try {
  bool success = await auth.[1](
    localizedReason: '[2]',
  );
  if (success) {
    print('[3]');
  } else {
    print('Authentication failed');
  }
} catch (e) {
  print('Error: $e');
}

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Aauthenticate

BPlease verify your identity

CAuthentication successful

DauthenticateWithBiometrics

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong method names.

Not handling exceptions properly.

The authenticate() method is called with a reason, and success or failure messages are printed accordingly.