{"id":7839,"date":"2013-10-02T08:51:24","date_gmt":"2013-10-02T12:51:24","guid":{"rendered":"http:\/\/blog.xamarin.com\/?p=7839"},"modified":"2013-10-02T08:51:24","modified_gmt":"2013-10-02T12:51:24","slug":"porting-existing-net-apps-to-android","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/xamarin\/porting-existing-net-apps-to-android\/","title":{"rendered":"Porting existing .NET apps to Android"},"content":{"rendered":"

Android’s growth to number one smartphone platform in terms of units shipped has resulted in a significant increase in interest from businesses and developers to ship applications that run natively on Android devices and that take advantage of features such as the camera and voice recognition. With Xamarin.Android, .NET developers have the ability to write native Android apps in C# using many of the existing .NET APIs that they are already familiar with, but what’s perhaps more attractive is the potential to share your existing .NET code to Android. \u00a0Almost any .NET codebase, including Windows Forms, WPF, ASP.NET, and Silverlight, has sharable code that can be ported to Xamarin.Android<\/a>, Xamarin.iOS<\/a>, Windows Phone & Windows Store.<\/p>\n

In my previous blogpost on Porting Existing .NET apps to iOS<\/a>, we looked at a step-by-step approach in porting an existing Silverlight application Diet Calculator<\/a> to Xamarin.iOS. In this post I will take a similar approach to what we did in the iOS porting sample to build the same app for Android phones using Xamarin.Android.<\/p>\n

Here\u2019s how the Silverlight sample looks:<\/p>\n

\"DietCalculator-Silverlight-MVC\"<\/a><\/p>\n

And here\u2019s how the ported application will look on an Android phone:<\/p>\n

\"DietCalculator-Android\"<\/a><\/p>\n

You can download the code used in this post for the Xamarin.Android DietCalculator sample from github<\/a>.<\/p>\n

Scan your Code for Mobilization<\/h2>\n

Xamarin\u2019s .NET Mobility Scanner<\/a> can determine the amount of code sharing and re-use you can expect from an existing .NET app or library and provide a detailed road-map of remaining work required to mobilize it. The Mobility Scanner analyzes compiled .NET assemblies and compares the APIs used with the capabilities of each platform. Since we are porting a Silverlight app we can easily extract the Silverlight_MVC.dll from the .XAP and upload that to the Scanner.<\/p>\n

\"DietCalculator-ScanReport\"<\/a><\/p>\n

We analyzed how mobile our Silverlight code is and concluded that 71% of the app code can be re-used. As per the detailed report<\/a>, all of the platform-specific method calls (i.e., code that we can\u2019t re-use across platforms) are user-interface specific and hence the business logic code that consists of Models, Controllers and Helpers from the Silverlight_MVC project can be re-used in our Xamarin.Android application! Now we are all set to build a Diet Calculator\u2019s User Interface native to the Android platform!<\/p>\n

Separate Reusable Code into a Core Library<\/h2>\n

When we set up our solution<\/a>, we followed the separation of responsibility principle and moved our Models, Controllers and Helpers from the Silverlight application to a core project called DietCalculator.Core and referred them using File Linking<\/a> on iOS and Silverlight projects. We will take the same approach and refer to these files from our Xamarin.Android project. Don\u2019t forget to check-out our detailed documentation on Building Cross Platform Applications<\/a>.<\/p>\n

Now that you\u2019ve got a fair idea about how we separated the business logic from the existing Silverlight_MVC project to a core project and referred them to iOS and Silverlight projects, let\u2019s create a Xamarin.Android project and re-use them there.<\/p>\n

Adding Xamarin.Android project to Visual Studio solution<\/h2>\n

Xamarin makes it possible for developers to use Visual Studio for Android & iOS Development: you can access your Android, iOS, Windows Phone & Windows Store app projects from one solution, code in on programming language, with one IDE.<\/p>\n

To create a new Android project in Visual Studio:<\/p>\n