Microsoft has had trouble getting developers to make apps for the Windows Store, so at last year's Build conference, it announced four ways to port apps from other platforms to Windows 10. Three of them are still available to developers—Web (Westminster), Win32 (Centennial), and iOS (Islandwood). The Android-to-Windows Project Astroia, however, is officially dead.
Microsoft pulled Astoria from builds of Windows 10 late last year, saying at the time it wasn't ready. Developers have been wondering what was up ever since, and now Microsoft says it has ended development. The rationale is bizarre, though. The iOS bridge still exists, and Microsoft says it heard from devs that having two mobile app bridges could be "confusing." Therefore, it decided to just do Islandwood and ditch Astoria.
At the same time, Microsoft is talking up the acquisition of Xamarin, which allows developers to create and manage cross-platform apps. Microsoft says this is a good alternative to Astoria, but the two projects are quite different. Astoria would have allowed Android apps written in Java to work on Windows 10 with minimal alteration, but Xamarin requires the code be in C#. That doesn't help Android developers very much.