How to on/off authentication fingerprint or face recognition when used Biometric

Question

I used Biometric to authentication finger print or face recognition. It working! But I want only use fingerprint or only use face recognition if my device is set to both. Can I do it or not? and how I can do it if it can? Here is my code

@RequiresApi(api = Build.VERSION_CODES.P)
public void authenticateUser(@NonNull Activity activity) {
    BiometricPrompt biometricPrompt = new BiometricPrompt.Builder(activity)
            .setTitle("Biometric Demo")
            .setSubtitle("Authentication is required to continue")
            .setDescription("This app uses biometric authentication to protect your data.")
            .setNegativeButton("Cancel", activity.getMainExecutor(),
                    (dialogInterface, i) -> {
                        mCallback.onCancel();
                    })
            .build();

    biometricPrompt.authenticate(mCancellationSignal, activity.getMainExecutor(),
            getAuthenticationCallback());
}

@RequiresApi(api = Build.VERSION_CODES.P)
private BiometricPrompt.AuthenticationCallback getAuthenticationCallback() {

    return new BiometricPrompt.AuthenticationCallback() {
        @Override
        public void onAuthenticationError(int errorCode,
                                          CharSequence errString) {
            super.onAuthenticationError(errorCode, errString);
            mCallback.onError();
        }

        @Override
        public void onAuthenticationHelp(int helpCode,
                                         CharSequence helpString) {
            super.onAuthenticationHelp(helpCode, helpString);
        }

        @Override
        public void onAuthenticationFailed() {
            super.onAuthenticationFailed();
        }

        @Override
        public void onAuthenticationSucceeded(
                BiometricPrompt.AuthenticationResult result) {
            super.onAuthenticationSucceeded(result);
            mCallback.onAuthenticated();
        }
    };
}

Answer 1

I want only use fingerprint or only use face recognition if my device is set to both. Can I do it or not?

Answer : As per latest APIs, You cant do it.

Biometrics feature is inconsistent among different devices. In my devices repo, I have Samsung S10 device and MI device, and both they have different behaviors. In Samsung S10 device, I can only set in device settings either FACE/FINGERPRINT. Whichever is set in device settings comes into action when I call authenticate API.

In MI device, along with Only Face/Only Fingerprint, I have option to set both. I think this is same like your case. If I set both option in device settings, after authenticate() I can authenticate either with Face or with Fingerprint.