Xamarin.Auth helps you authenticate users via standard authentication mechanisms (e.g. OAuth 1.0 and 2.0), and store user credentials. It's also straightforward to add support for non-standard authentication schemes. The library is cross-platform, so once you learn it on iOS, you're all set on Android.
using Xamarin.Auth;
var auth = new OAuth2Authenticator (
clientId: "App ID from https://developers.facebook.com/apps",
scope: "",
authorizeUrl: new Uri ("https://m.facebook.com/dialog/oauth/"),
redirectUrl: new Uri ("http://www.facebook.com/connect/login_success.html"));
auth.Completed += (sender, eventArgs) => {
DismissViewController (true, null);
if (eventArgs.IsAuthenticated) {
// Use eventArgs.Account to do wonderful things
}
}
PresentViewController (auth.GetUI (), true, null);
It's that easy to authenticate users!
Some screenshots assembled with PlaceIt.