var result = await CrossFingerprint.Current.AuthenticateAsync("Prove you have fingers!");
if (result.Authenticated)
{
    // do secret stuff :)
}
else
{
    // not allowed to do secret stuff :(
}

var fpService = Mvx.Resolve<IFingerprint>(); // or use dependency injection and inject IFingerprint

var result = await fpService.AuthenticateAsync("Prove you have mvx fingers!");
if (result.Authenticated)
{
    // do secret stuff :)
}
else
{
    // not allowed to do secret stuff :(
}

/// <summary>
/// Checks the availability of fingerprint authentication.
/// Checks are performed in this order:
/// 1. API supports accessing the fingerprint sensor
/// 2. Permission for accessint the fingerprint sensor granted
/// 3. Device has sensor
/// 4. Fingerprint has been enrolled
/// <see cref="FingerprintAvailability.Unknown"/> will be returned if the check failed 
/// with some other platform specific reason.
/// </summary>
/// <param name="allowAlternativeAuthentication">
/// En-/Disables the use of the PIN / Passwort as fallback.
/// Supported Platforms: iOS, Mac
/// Default: false
/// </param>
Task<FingerprintAvailability> GetAvailabilityAsync(bool allowAlternativeAuthentication = false);

/// <summary>
/// Checks if <see cref="GetAvailabilityAsync"/> returns <see cref="FingerprintAvailability.Available"/>.
/// </summary>
/// <param name="allowAlternativeAuthentication">
/// En-/Disables the use of the PIN / Passwort as fallback.
/// Supported Platforms: iOS, Mac
/// Default: false
/// </param>
/// <returns><c>true</c> if Available, else <c>false</c></returns>
Task<bool> IsAvailableAsync(bool allowAlternativeAuthentication = false);

/// <summary>
/// Requests the authentication.
/// </summary>
/// <param name="reason">Reason for the fingerprint authentication request. Displayed to the user.</param>
/// <param name="cancellationToken">Token used to cancel the operation.</param>
/// <returns>Authentication result</returns>
Task<FingerprintAuthenticationResult> AuthenticateAsync(string reason, CancellationToken cancellationToken = default(CancellationToken));

/// <summary>
/// Requests the authentication.
/// </summary>
/// <param name="authRequestConfig">Configuration of the dialog that is displayed to the user.</param>
/// <param name="cancellationToken">Token used to cancel the operation.</param>
/// <returns>Authentication result</returns>
Task<FingerprintAuthenticationResult> AuthenticateAsync(AuthenticationRequestConfiguration authRequestConfig, CancellationToken cancellationToken = default(CancellationToken));

/// <summary>
/// Indicatates whether the authentication was successful or not.
/// </summary>
public bool Authenticated { get { return Status == FingerprintAuthenticationResultStatus.Succeeded; } }

/// <summary>
/// Detailed information of the authentication.
/// </summary>
public FingerprintAuthenticationResultStatus Status { get; set; }

/// <summary>
/// Reason for the unsucessful authentication.
/// </summary>
public string ErrorMessage { get; set; }

var result = await CrossFingerprint.Current.AuthenticateAsync("Prove you have fingers!");
if (result.Authenticated)
{
    // do secret stuff :)
}
else
{
    // not allowed to do secret stuff :(
}

var fpService = Mvx.Resolve<IFingerprint>(); // or use dependency injection and inject IFingerprint

var result = await fpService.AuthenticateAsync("Prove you have mvx fingers!");
if (result.Authenticated)
{
    // do secret stuff :)
}
else
{
    // not allowed to do secret stuff :(
}

//Create mock with LigthMock (http://www.lightinject.net/)
var mockFingerprintContext = new MockContext<IFingerprint>();
var mockFingerprint = new CrossFingerprintMock(mockFingerprintContext);

mockFingerprintContext.Current = mockFingerprint;

CrossFingerprint.SetCurrentActivityResolver(() => CrossCurrentActivity.Current.Activity);

public class MyCustomDialogFragment : FingerprintDialogFragment
{
    public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        var view = base.OnCreateView(inflater, container, savedInstanceState);
        view.Background = new ColorDrawable(Color.Magenta); // make it fancyyyy :D
        return view;
    }
}

CrossFingerprint.SetDialogFragmentType<MyCustomDialogFragment>();