Xamarin supports a subset of the .NET framework, but for the most part includes all the standard APIs you would expect in the .NET base class libraries. Because of this, a large portion of C# open-source libraries can be used directly in Xamarin projects. Additionally, if an open source project doesn't have a Xamarin or portable class library version, porting the code to be used in a Xamarin project can often be very straightforward. Xamarin also supports calling native Objective-C and Java libraries, so we will explore these as additional means of reusing existing code.
In this chapter, we will cover the following: