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();
}
// Initialize CameraX, and prepare to bind the camera use cases
private void SetUpCamera()
{
var cameraProviderFuture = ProcessCameraProvider.GetInstance(RequireContext());
cameraProviderFuture.AddListener(new Java.Lang.Runnable(() =>
{
// CameraProvider
cameraProvider = cameraProviderFuture.Get() as ProcessCameraProvider;;
// Select lensFacing depending on the available cameras
if (HasBackCamera())
{
lensFacing = CameraSelector.LensFacingBack;
}
else if (HasFrontCamera())
{
lensFacing = CameraSelector.LensFacingFront;
}
else
{
throw new Java.Lang.IllegalStateException("Back and front camera are unavailable");
}
// Enable or disable switching between cameras
UpdateCameraSwitchButton();
// Build and bind the camera use cases
BindCameraUseCases();
}), ContextCompat.GetMainExecutor(RequireContext()));
}
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 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.");
}
}
private void TakePhoto()
{
// Get a stable reference of the modifiable image capture use case
var imageCapture = this.imageCapture;
if (imageCapture == null)
{
return;
}
// Create time-stamped output file to hold the image
var photoFile = new File(outputDirectory, new Java.Text.SimpleDateFormat(FILENAME_FORMAT, Locale.Us).Format(JavaSystem.CurrentTimeMillis()) + ".jpg");
// Create output options object which contains file + metadata
var outputOptions = new ImageCapture.OutputFileOptions.Builder(photoFile).Build();
// Set up image capture listener, which is triggered after photo has been taken
imageCapture.TakePicture(outputOptions, ContextCompat.GetMainExecutor(this), new ImageSaveCallback(
onErrorCallback: (exc) =>
{
var msg = $"Photo capture failed: {exc.Message}";
Log.Error(TAG, msg, exc);
Toast.MakeText(this.BaseContext, msg, ToastLength.Short).Show();
},
onImageSaveCallback: (output) =>
{
var savedUri = output.SavedUri;
var msg = $"Photo capture succeeded: {savedUri}";
Log.Debug(TAG, msg);
Toast.MakeText(this.BaseContext, msg, ToastLength.Short).Show();
}
));
}
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));
}
private void FindAndOpenCamera()
{
bool cameraPermissions = CheckCameraPermissions();
if (!cameraPermissions)
{
return;
}
string errorMessage = "Unknown error";
bool foundCamera = false;
IListenableFuture cameraProviderFuture = ProcessCameraProvider.GetInstance(this);
cameraProviderFuture.AddListener(new Runnable(() =>
{
// Camera provider is now guaranteed to be available
mCameraProvider = cameraProviderFuture.Get() as ProcessCameraProvider;
try
{
// Find first back-facing camera that has necessary capability.
CameraSelector cameraSelector = new CameraSelector.Builder().RequireLensFacing((int)mLensFacing).Build();
// Find a good size for output - largest 4:3 aspect ratio that's less than 720p
Preview.Builder previewBuilder = new Preview.Builder()
.SetTargetAspectRatio(AspectRatio.Ratio43);
Camera2Interop.Extender previewExtender = new Camera2Interop.Extender(previewBuilder);
previewExtender.SetSessionCaptureCallback(mCaptureCallback);
Preview preview = previewBuilder.Build();
// Must unbind the use-cases before rebinding them
mCameraProvider.UnbindAll();
ICamera camera = mCameraProvider.BindToLifecycle(
this as ILifecycleOwner, cameraSelector, preview);
if (camera != null)
{
// Found suitable camera - get info, open, and set up outputs
mCameraInfo = camera.CameraInfo;
mCameraControl = camera.CameraControl;
preview.SetSurfaceProvider(this);
foundCamera = true;
}
if (!foundCamera)
{
errorMessage = GetString(Resource.String.camera_no_good);
}
SwitchRenderMode(0);
}
catch (CameraAccessException e)
{
errorMessage = GetErrorString(e);
}
if (!foundCamera)
{
ShowErrorDialog(errorMessage);
}
}), ContextCompat.GetMainExecutor(this));
}
void ViewTreeObserver.IOnGlobalLayoutListener.OnGlobalLayout()
{
binding !.previewView.ViewTreeObserver !.RemoveOnGlobalLayoutListener(this);
cameraProviderFuture !.AddListener(new Runnable(() =>
{
var cameraProvider = (ProcessCameraProvider)cameraProviderFuture.Get() !;
BindScan(cameraProvider, binding !.previewView.Width, binding !.previewView.Height);
}), ContextCompat.GetMainExecutor(this));
}
private void StartCamera()
{
var cameraProviderFuture = ProcessCameraProvider.GetInstance(this);
cameraProviderFuture.AddListener(new Runnable(() =>
{
_cameraProvider = (ProcessCameraProvider)cameraProviderFuture.Get();
_previewView.PostDelayed(BindCameraUseCases, 16);
}), ContextCompat.GetMainExecutor(this));
}
/// <summary>
/// https://codelabs.developers.google.com/codelabs/camerax-getting-started#3
/// </summary>
private void StartCamera()
{
var cameraProviderFuture = ProcessCameraProvider.GetInstance(this);
cameraProviderFuture.AddListener(new Runnable(() =>
{
// Used to bind the lifecycle of cameras to the lifecycle owner
var cameraProvider = (ProcessCameraProvider)cameraProviderFuture.Get();
// Preview
var preview = new Preview.Builder().Build();
preview.SetSurfaceProvider(viewFinder.CreateSurfaceProvider());
// Take Photo
this.imageCapture = new ImageCapture.Builder().Build();
// Frame by frame analyze
var imageAnalyzer = new ImageAnalysis.Builder().Build();
imageAnalyzer.SetAnalyzer(cameraExecutor, new LuminosityAnalyzer(luma =>
Log.Debug(TAG, $"Average luminosity: {luma}")
));
// Select back camera as a default, or front camera otherwise
CameraSelector cameraSelector = null;
if (cameraProvider.HasCamera(CameraSelector.DefaultBackCamera) == true)
{
cameraSelector = CameraSelector.DefaultBackCamera;
}
else if (cameraProvider.HasCamera(CameraSelector.DefaultFrontCamera) == true)
{
cameraSelector = CameraSelector.DefaultFrontCamera;
}
else
{
throw new System.Exception("Camera not found");
}
try
{
// Unbind use cases before rebinding
cameraProvider.UnbindAll();
// Bind use cases to camera
cameraProvider.BindToLifecycle(this, cameraSelector, preview, imageCapture, imageAnalyzer);
}
catch (Exception exc)
{
Log.Debug(TAG, "Use case binding failed", exc);
Toast.MakeText(this, $"Use case binding failed: {exc.Message}", ToastLength.Short).Show();
}
}), ContextCompat.GetMainExecutor(this)); //GetMainExecutor: returns an Executor that runs on the main thread.
}
/// <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);
}
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);
}
private void ShowBiometicPrompt(IBioAuthCompleted bioAuthCompleted)
{
var activity = (FragmentActivity)CrossCurrentActivity.Current.Activity;
var executor = ContextCompat.GetMainExecutor(activity);
var callback = new BiometricAuthenticationCallback
{
Success = (AndroidX.Biometric.BiometricPrompt.AuthenticationResult result) => {
try
{
bioAuthCompleted.OnCompleted(BioAuthStatus.SUCCESS);
}
catch (SignatureException)
{
throw new RuntimeException();
}
},
Failed = () => {
// TODO: Show error.
bioAuthCompleted.OnCompleted(BioAuthStatus.FAILED);
},
Help = (BiometricAcquiredStatus helpCode, ICharSequence helpString) => {
// TODO: What do we do here?
}
};
//Create prompt info
var promptInfo = new AndroidX.Biometric.BiometricPrompt.PromptInfo.Builder()
.SetTitle("Biometric login for my app")
.SetSubtitle("Log in using your biometric credential")
.SetNegativeButtonText("Use account password")
.Build();
//Create prompt
var biometricPrompt = new AndroidX.Biometric.BiometricPrompt(activity, executor, callback);
//call Authenticate
biometricPrompt.Authenticate(promptInfo);
}
private BioAuthnPrompt CreateBioAuthnPrompt()
{
BioAuthnCallback callback = new FidoBioAuthnCallback();
return(new BioAuthnPrompt(this, ContextCompat.GetMainExecutor(this), callback));
}