private void ShowBiometricPrompt()
{
var executor = ContextCompat.GetMainExecutor(this);
var passwordStorage = new PasswordStorageManager(this);
var callback = new AuthenticationCallback();
callback.Success += async(_, result) =>
{
string password;
try
{
password = passwordStorage.Fetch(result.CryptoObject.Cipher);
}
catch
{
Toast.MakeText(this, Resource.String.genericError, ToastLength.Short);
return;
}
await AttemptUnlock(password);
};
callback.Failed += delegate
{
FocusPasswordText();
};
callback.Error += (_, result) =>
{
Toast.MakeText(this, result.Message, ToastLength.Short).Show();
FocusPasswordText();
};
_prompt = new BiometricPrompt(this, executor, callback);
var promptInfo = new BiometricPrompt.PromptInfo.Builder()
.SetTitle(GetString(Resource.String.unlock))
.SetSubtitle(GetString(Resource.String.unlockBiometricsMessage))
.SetNegativeButtonText(GetString(Resource.String.cancel))
.SetConfirmationRequired(false)
.SetAllowedAuthenticators(BiometricManager.Authenticators.BiometricStrong)
.Build();
Cipher cipher;
try
{
cipher = passwordStorage.GetDecryptionCipher();
}
catch
{
_canUseBiometrics = false;
_useBiometricsButton.Enabled = false;
return;
}
_prompt.Authenticate(promptInfo, new BiometricPrompt.CryptoObject(cipher));
}
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.activityLogin);
var executor = ContextCompat.GetMainExecutor(this);
var callback = new AuthenticationCallback();
callback.Success += OnSuccess;
callback.Error += OnError;
var prompt = new BiometricPrompt(this, executor, callback);
var promptInfo = new BiometricPrompt.PromptInfo.Builder()
.SetTitle(GetString(Resource.String.login))
.SetSubtitle(GetString(Resource.String.loginMessage))
.SetDeviceCredentialAllowed(true)
.Build();
prompt.Authenticate(promptInfo);
}