The Android platform provides a framework API that applications can use to interact with the underlying Android system. The framework API consists of: A core set of packages and classes. A set of permissions that applications can request, as well as permission enforcements included in the system

Mono for Android is a runtime and development stack that allows . NET developers to leverage their knowledge of Visual Studio and C# to develop applications for Android-based devices. It interprets the Mono byte code and handles communication with the Dalvik runtime for calls to native Android APIs

OpenTK, also known as The Open Toolkit library, is a C# graphics library superseding the Tao Framework. It provides access to graphics tools contained in OpenGL, OpenCL, and OpenAL to a variety of CLR-based languages Use OpenTK to add cross-platform 3d graphics, audio, compute and haptics to your C# application. Integrate it into your existing user interface or use it standalone without any external dependencies.

Create native iOS, Android, Mac and Windows apps in C#. We created Xamarin because we knew there had to be a better way – a better way to design apps, to develop apps, to integrate apps, to test apps and more. We’re developers, so we know what developers want: a modern programming language, code sharing across all platforms, prebuilt backend connectors and no-compromise native user interfaces.