How to prompt user to enroll biometrics on their phone

Question

I am using local_auth for biometric authorization.

In case that the device does have biometric support but the user has not enrolled any biometrics (i.e. auth.getAvailableBiometrics() is empty) is there a way to launch the phone's screen that prompts the user to enrol their biometric data?

I'm sorry if this is a stupid question, I've never done this type of authorization myself, so I don't know how it works.

Answer 1

You can use the local_auth package for implementing this

To check whether there is local authentication available on this device or not, call canCheckBiometrics (if you need biometrics support) and/or isDeviceSupported() (if you just need some device-level authentication):

import 'package:local_auth/local_auth.dart';

final LocalAuthentication auth = LocalAuthentication();
final bool canAuthenticateWithBiometrics = await 

auth.canCheckBiometrics;
final bool canAuthenticate = canAuthenticateWithBiometrics || await auth.isDeviceSupported();

Reference doc: Flutter - local_auth

UPDATE

You can launch the security settings (where fingerprint option is available) using the below code:

startActivity(new Intent(android.provider.Settings.ACTION_SECURITY_SETTINGS));

with API >= P there is Settings.ACTION_FINGERPRINT_ENROLL & BiometricPrompt.

@RequiresApi(api = Build.VERSION_CODES.P)
private void startFingerprintEnrollment(@NonNull AppCompatActivity activity) {
    Intent intent = new Intent(Settings.ACTION_FINGERPRINT_ENROLL);
    activity.startActivityForResult(intent, REQUESTCODE_FINGERPRINT_ENROLLMENT);
}

For API >= M:

@SuppressWarnings("deprecation")
@RequiresApi(api = Build.VERSION_CODES.M)
private void gotoSecuritySettings(@NonNull AppCompatActivity activity) {
    Intent intent = new Intent(Settings.ACTION_SECURITY_SETTINGS);
    activity.startActivityForResult(intent, REQUESTCODE_SECURITY_SETTINGS);
}