Unlike the video showing how to make a windows store application talk to azure active directory (which entails using a store redirect URI and a clientid), the xamarin apps for ios and android induce AAD to send the token to the azure mobile website. The site then returns a custom token to the app:
the code is http://1drv.ms/1rFVG9j on ondrive. Its is a merge of the hellotest app (from the native Android ADAL project for Xamarin bindings, on github) and the sample azure mobile site app for Xamarin/Android. Quite a few changes were made.
The activity element (for continuance tasking) and the permissions:
the promise closure (that complets the login, with the webAPI client UA)
initialization, button callback, and continuance handler:
Our goal was NOT to have the token auto-posted to the mobile site (which then mints a session token); but capture the AAD tokens directly in the client (which then uses LoginAsync() to create a web service session).
The major gotcha, on binding to the Xamarin binding DLL (wrapping the java objects) is that one must reference the DLL in the obj/ directory of the bindings creation project using the browser file picker. Do not try to bind to the solution DLL (referring to the .dll in debug/ or release/).