public void EnableBiometrics(Action <bool> callback)
{
var passwordStorage = new PasswordStorageManager(this);
var executor = ContextCompat.GetMainExecutor(this);
var authCallback = new AuthenticationCallback();
authCallback.Success += async(_, result) =>
{
try
{
var password = await SecureStorageWrapper.GetDatabasePassword();
passwordStorage.Store(password, result.CryptoObject.Cipher);
}
catch (Exception e)
{
Logger.Error(e);
callback(false);
return;
}
callback(true);
};
authCallback.Failed += delegate
{
callback(false);
};
authCallback.Error += delegate
{
// Do something, probably
callback(false);
};
var prompt = new BiometricPrompt(this, executor, authCallback);
var promptInfo = new BiometricPrompt.PromptInfo.Builder()
.SetTitle(GetString(Resource.String.setupBiometricUnlock))
.SetNegativeButtonText(GetString(Resource.String.cancel))
.SetConfirmationRequired(false)
.SetAllowedAuthenticators(BiometricManager.Authenticators.BiometricStrong)
.Build();
Cipher cipher;
try
{
cipher = passwordStorage.GetEncryptionCipher();
}
catch (Exception e)
{
Logger.Error(e);
passwordStorage.Clear();
callback(false);
return;
}
prompt.Authenticate(promptInfo, new BiometricPrompt.CryptoObject(cipher));
}
public FingerprintService(
FragmentActivity fragmentActivity,
Context applicationContext,
IObservable <Unit> applicationActivated,
CoreDispatcher dispatcher,
IScheduler backgroundScheduler,
FuncAsync <BiometricPrompt.PromptInfo> promptInfoBuilder)
{
fragmentActivity.Validation().NotNull(nameof(fragmentActivity));
applicationActivated.Validation().NotNull(nameof(applicationActivated));
backgroundScheduler.Validation().NotNull(nameof(backgroundScheduler));
_dispatcher = dispatcher ?? throw new ArgumentNullException(nameof(dispatcher));
_promptInfoBuilder = promptInfoBuilder ?? throw new ArgumentNullException(nameof(promptInfoBuilder));
var executor = ContextCompat.GetMainExecutor(applicationContext);
var callback = new AuthenticationCallback(OnAuthenticationSucceeded, OnAuthenticationFailed, OnAuthenticationError);
_BiometricPrompt = new BiometricPrompt(fragmentActivity, executor, callback);
_BiometricManager = BiometricManager.From(Application.Context);
_keyStore = KeyStore.GetInstance(ANDROID_KEYSTORE);
_keyStore.Load(null);
_canAuthenticate =
applicationActivated
.ObserveOn(backgroundScheduler)
.StartWith(backgroundScheduler, Unit.Default)
.Select(_ => _BiometricManager.CanAuthenticate())
.Replay(1, backgroundScheduler)
.RefCount();
}
public void Authenticate(Func <Task> action, string title)
{
try
{
switch (BiometricManager.From(_context).CanAuthenticate())
{
case BiometricManager.BiometricSuccess:
var biometricPrompt = new BiometricPrompt(MainActivity, ContextCompat.GetMainExecutor(_context), GetBiometricAuthenticationCallback(action));
var promptInfo = new BiometricPrompt.PromptInfo.Builder()
.SetTitle(title == null ? "Biometric login for Falcon" : $"{title}...")
.SetNegativeButtonText("Cancel")
.Build();
biometricPrompt.Authenticate(promptInfo);
return;
case BiometricManager.BiometricErrorHwUnavailable:
Tools.DisplayAlert(message: "Biometric hardware is currently unavailable. Try again later.");
return;
case BiometricManager.BiometricErrorNoneEnrolled:
Tools.DisplayAlert(message: "The device does not have any biometrics enrolled. Please make sure you have set up any available biometrics in your phone Settings.");
return;
default:
return;
}
}
catch (Exception ex)
{
//DisplayAlertError("Something went wrong while using biometric authentication.");
}
}
protected override async Task <FingerprintAuthenticationResult> NativeAuthenticateAsync(AuthenticationRequestConfiguration authRequestConfig, CancellationToken cancellationToken)
{
if (string.IsNullOrWhiteSpace(authRequestConfig.Title))
{
throw new ArgumentException("Title must not be null or empty on Android.", nameof(authRequestConfig.Title));
}
if (!(CrossFingerprint.CurrentActivity is FragmentActivity))
{
throw new InvalidOperationException($"Expected current activity to be '{typeof(FragmentActivity).FullName}' but was '{CrossFingerprint.CurrentActivity?.GetType().FullName}'. " +
"You need to use AndroidX. Have you installed Xamarin.AndroidX.Migration in your Android App project!?");
}
try
{
var cancel = string.IsNullOrWhiteSpace(authRequestConfig.CancelTitle) ?
Application.Context.GetString(Android.Resource.String.Cancel) :
authRequestConfig.CancelTitle;
var handler = new AuthenticationHandler();
var builder = new BiometricPrompt.PromptInfo.Builder()
.SetTitle(authRequestConfig.Title)
.SetConfirmationRequired(authRequestConfig.ConfirmationRequired)
.SetDescription(authRequestConfig.Reason);
if (authRequestConfig.AllowAlternativeAuthentication)
{
// It's not allowed to allow alternative auth & set the negative button
builder = builder.SetDeviceCredentialAllowed(authRequestConfig.AllowAlternativeAuthentication);
}
else
{
builder = builder.SetNegativeButtonText(cancel);
}
var info = builder.Build();
var executor = Executors.NewSingleThreadExecutor();
var activity = (FragmentActivity)CrossFingerprint.CurrentActivity;
using var dialog = new BiometricPrompt(activity, executor, handler);
await using (cancellationToken.Register(() => dialog.CancelAuthentication()))
{
dialog.Authenticate(info);
var result = await handler.GetTask();
TryReleaseLifecycleObserver(activity, dialog);
return(result);
}
}
catch (Exception e)
{
return(new FingerprintAuthenticationResult
{
Status = FingerprintAuthenticationResultStatus.UnknownError,
ErrorMessage = e.Message
});
}
}
private void ShowBiometricPrompt()
{
var executor = ContextCompat.GetMainExecutor(Context);
var passwordStorage = new PasswordStorageManager(Context);
var callback = new AuthenticationCallback();
callback.Succeeded += (_, result) =>
{
string password;
try
{
password = passwordStorage.Fetch(result.CryptoObject.Cipher);
}
catch (Exception e)
{
Logger.Error(e);
Toast.MakeText(Context, Resource.String.genericError, ToastLength.Short);
return;
}
UnlockAttempted?.Invoke(this, password);
};
callback.Failed += delegate
{
FocusPasswordText();
};
callback.Errored += (_, result) =>
{
Toast.MakeText(Context, 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();
try
{
var cipher = passwordStorage.GetDecryptionCipher();
_prompt.Authenticate(promptInfo, new BiometricPrompt.CryptoObject(cipher));
}
catch (Exception e)
{
Logger.Error(e);
_canUseBiometrics = false;
_useBiometricsButton.Enabled = false;
FocusPasswordText();
}
}
public void StartListening(BiometricPrompt.AuthenticationCallback callback)
{
Kp2aLog.Log("Fingerprint: StartListening ");
var executor = Executors.NewSingleThreadExecutor();
_biometricPrompt = new BiometricPrompt(_activity, executor, callback);
BiometricPrompt.PromptInfo promptInfo = new BiometricPrompt.PromptInfo.Builder()
.SetTitle(_activity.GetString(AppNames.AppNameResource))
.SetSubtitle(_activity.GetString(Resource.String.unlock_database_title))
.SetNegativeButtonText(_activity.GetString(Android.Resource.String.Cancel))
.SetConfirmationRequired(false)
.Build();
_biometricPrompt.Authenticate(promptInfo, _cryptoObject);
}
/// <summary>
/// Initializes a new instance of the <see cref="BiometryService" /> class.
/// </summary>
/// <param name="fragmentActivity"></param>
/// <param name="dispatcher"></param>
/// <param name="promptInfoBuilder"></param>
/// <param name="authenticators"></param>
public BiometryService(
FragmentActivity fragmentActivity,
CoreDispatcher dispatcher,
FuncAsync <BiometricPrompt.PromptInfo> promptInfoBuilder)
{
fragmentActivity.Validation().NotNull(nameof(fragmentActivity));
_dispatcher = dispatcher ?? throw new ArgumentNullException(nameof(dispatcher));
_promptInfoBuilder = promptInfoBuilder ?? throw new ArgumentNullException(nameof(promptInfoBuilder));
_applicationContext = Application.Context;
var executor = ContextCompat.GetMainExecutor(_applicationContext);
var callback = new AuthenticationCallback(OnAuthenticationSucceeded, OnAuthenticationFailed, OnAuthenticationError);
_biometricPrompt = new BiometricPrompt(fragmentActivity, executor, callback);
_biometricManager = BiometricManager.From(_applicationContext);
_keyStore = KeyStore.GetInstance(ANDROID_KEYSTORE);
_keyStore.Load(null);
}
private void ShowBiometricPrompt(Java.Security.Signature signature)
{
// Create biometric prompt
var activity = MainActivity.FormsContext;
var negativeButtonListener = new DialogInterfaceOnClickListener(() => {
// Do something here.
});
biometricPrompt = new BiometricPrompt.Builder(activity)
.SetDescription("Never Been Easier")
.SetTitle("Biometric Prompt Authentication")
.SetSubtitle("Please allow Xamarin Life to authenticate")
.SetNegativeButton("Cancel", activity.MainExecutor, negativeButtonListener)
.Build();
// Show biometric prompt
var cancellationSignal = new CancellationSignal();
var authenticationCallback = GetAuthenticationCallback();
biometricPrompt.Authenticate(new BiometricPrompt.CryptoObject(signature), cancellationSignal, activity.MainExecutor, authenticationCallback);
}
public void Authenticate(string userId, Action onSuccess, Action onFailure)
{
OnSuccess = onSuccess;
OnFailure = onFailure;
if (IsBiometricPromptEnabled)
{
newCancelSignal = new Android.OS.CancellationSignal();
prompt = new BiometricPrompt.Builder(CrossCurrentActivity.Current.Activity)
.SetTitle("ManageGo")
.SetSubtitle("Fingerprint Login")
.SetDescription($"Place finger on the home button to log in as {userId}")
.SetNegativeButton("CANCEL", CrossCurrentActivity.Current.Activity.MainExecutor,
new DialogListener(this)).Build();
prompt.Authenticate(newCancelSignal, CrossCurrentActivity.Current.Activity.MainExecutor, new BiometricCallback(this));
}
else
{
cancellationSignal = new Android.Support.V4.OS.CancellationSignal();
var callback = new SimpleAuthCallbacks(this);
FingerprintManager.Authenticate(null, 0, cancellationSignal, callback, null);
}
}
/// <summary>
/// Removes the lifecycle observer that is set by the BiometricPrompt from the lifecycleOwner.
/// See: https://stackoverflow.com/a/59637670/1489968
/// TODO: The new implementation of BiometricPrompt doesn't use this mechanism anymore. Recheck this code after Xamarin.AndroidX.Biometric has been updated.
/// </summary>
/// <param name="lifecycleOwner">Lifecycle owner where the observer was added.</param>
/// <param name="dialog">Used BiometricPrompt</param>
private static void TryReleaseLifecycleObserver(ILifecycleOwner lifecycleOwner, BiometricPrompt dialog)
{
var promptClass = Java.Lang.Class.FromType(dialog.GetType());
var fields = promptClass.GetDeclaredFields();
var lifecycleObserverField = fields?.FirstOrDefault(f => f.Name == "mLifecycleObserver");
if (lifecycleObserverField is null)
{
return;
}
lifecycleObserverField.Accessible = true;
var lastLifecycleObserver = lifecycleObserverField.Get(dialog).JavaCast <ILifecycleObserver>();
var lifecycle = lifecycleOwner.Lifecycle;
if (lastLifecycleObserver is null || lifecycle is null)
{
return;
}
lifecycle.RemoveObserver(lastLifecycleObserver);
}