Hi
As far as I know you, an Android app cannot interact directly with Windows login prompt, even if it is on a webpage. Only thing I can think of is for you to design your own login page and use that in your app via a WebView, although I'm not entirely sure if that would even work. If it's just a webpage you want to display, then why do you need an app? Couldn't you just design the page as a "Responsive web app" so it formats on any device? I did something similar for a project and it looked just like a mobile app even though it was a ASP.net page behind the scenes.