Xamarin Shared Projects vs Portable class libraries

Xamarin Shared Projects vs Portable Class Libraries

When developing cross-platform mobile applications using Xamarin, you often need to share code across different platforms. Xamarin provides two primary mechanisms for code sharing: Shared Projects and Portable Class Libraries (PCLs). This article explores the differences between these approaches and helps you choose the best option for your project.

Shared Projects

What are Shared Projects?

Shared projects allow you to share code and resources between multiple platform projects. It’s essentially a folder containing your source code, which is referenced by each platform project that needs to access it. The compiler handles building the shared code for each platform, ensuring compatibility.

Advantages:

• Simple setup and usage.
• Direct access to platform-specific APIs from shared code.
• Supports sharing resources like images and XAML.

Disadvantages:

• Code can become platform-dependent, potentially introducing inconsistencies.
• Limited support for platform-specific NuGet packages.
• Can be more difficult to maintain complex projects.

Portable Class Libraries (PCLs)

What are PCLs?

Portable Class Libraries define a specific subset of .NET APIs that are guaranteed to be available across multiple platforms. You create a PCL project that references only these shared APIs, ensuring your code is truly portable.

Advantages:

• Enforces true platform-independent code.
• Supports NuGet package consumption for all platforms.
• Easier to maintain and scale for larger projects.

Disadvantages:

• More complex setup and configuration.
• Limited access to platform-specific APIs.
• No direct support for sharing resources.

Comparison Table

Choosing the Right Approach

The choice between Shared Projects and PCLs depends on your specific project requirements:

• Shared Projects are suitable for projects with simple code sharing needs and a strong focus on platform-specific functionality. They are easier to set up and use, but might require more careful code management to ensure consistency across platforms.
• PCLs are better suited for projects demanding true platform independence and the ability to utilize third-party NuGet packages across all platforms. They offer more structured code sharing but involve a slightly more complex setup process.

Example Code: Hello World

Shared Project:

// SharedProject.cs
public class HelloWorld
{
    public static string GetMessage()
    {
        return "Hello, World!";
    }
}

Portable Class Library:

// PCL.cs
using System;

public class HelloWorld
{
    public string GetMessage()
    {
        return "Hello, World!";
    }
}

// Example usage (for both approaches)
Console.WriteLine(HelloWorld.GetMessage());

// Output:
Hello, World!

In this example, both approaches achieve the same result: printing “Hello, World!”. However, the PCL ensures platform independence, while the Shared Project may require platform-specific modifications depending on the underlying implementation.

Conclusion

Both Shared Projects and Portable Class Libraries provide valuable tools for code sharing in Xamarin development. Understanding their strengths and weaknesses allows you to make an informed decision based on your project’s requirements. Shared Projects offer simplicity and direct platform access, while PCLs prioritize platform independence and package management. The best choice ultimately depends on your project’s specific needs.