Use of ISignInDelegate interface

ViewController.cs

public partial class ViewController : UIViewController, ISignInUIDelegate, ISignInDelegate
{
  public ViewController (IntPtr handle) : base (handle)
  {
  }

  public override void ViewDidLoad ()
  {
    base.ViewDidLoad ();

    // TODO(developer) Configure the sign-in button look/feel
    SignIn.SharedInstance.Delegate = this;
    SignIn.SharedInstance.UIDelegate = this;

    // Automatically sign in the user.
    SignIn.SharedInstance.SignInUserSilently ();
    ToggleAuthUI ();

    statusText.Text = "Google Sign in\niOS Demo";

  }

  partial void didTapSignOut (NSObject sender)
  {
    SignIn.SharedInstance.SignOutUser ();
    ToggleAuthUI ();
  }

  partial void didTapDisconnect (NSObject sender)
  {
    SignIn.SharedInstance.DisconnectUser ();
  }

  void ToggleAuthUI ()
  {
    if (SignIn.SharedInstance.CurrentUser == null || SignIn.SharedInstance.CurrentUser.Authentication == null) {
      // Not signed in
      statusText.Text = "Google Sign in\niOS Demo";
      signInButton.Hidden = false;
      signOutButton.Hidden = true;
      disconnectButton.Hidden = true;
    } else {
      // Signed in
      signInButton.Hidden = true;
      signOutButton.Hidden = false;
      disconnectButton.Hidden = false;
    }
  }

  public override UIStatusBarStyle PreferredStatusBarStyle ()
  {
    return UIStatusBarStyle.LightContent;
  }


  #region Sign In Delegate

  public void DidSignIn (SignIn signIn, GoogleUser user, NSError error)
  {
    if (user != null && error == null) {
      statusText.Text = string.Format ("Signed in user: {0}", user.Profile.Name);
      ToggleAuthUI ();
    }
  }

  [Export ("signIn:didDisconnectWithUser:withError:")]
  public void DidDisconnect (SignIn signIn, GoogleUser user, NSError error)
  {
    statusText.Text = "Disconnected user";
    ToggleAuthUI ();
  }

  #endregion
}