I am currently working on a Xamarin project that we started as a Xamarin Android application. We recently tried to migrate the application to a Xamarin Forms project but it turned out to be pretty non trivial.
Xamarin is a cross platform solution for building mobile apps that run on Android, iOS and Windows Phone, but Xamarin is not quite cross platform as are Html 5 based solutions such as Cordova and PhoneGap in which a single application is built for all mobile platforms.
Xamarin allows developers to leverage native APIs as well as to get a strong native look and feel while sharing as much code as possible.
A Xamarin.Forms solution (in Visual Studio) contains usually the following projects which contains the artifacts shared between all platforms:
- The core logic project that is usually a PCL or a netstandard library
- A Xamarin.Forms project containing XAML shared views that can be used in all the supported mobile platforms. Interfaces abstracting platform specific APIs can be defined here as well
The visual studio solution contains also a project for each targeted platform, these platform specific projects contains the following elements:
- Concrete implementation of abstract interfaces using the platform specific APIs
- Complex views that require high coupling with the native SDK (displaying a Google Maps map for example)
- “Style sheets” (usually xml) specifying how the shared XAML views should be rendered in the specific platform
When deployment on multiple platforms is needed always start with a Xamarin.Forms project even when you are focusing on a single platform in the early stages and make sure to place the core logic in PCL or netstandard library project.
We thought that it would be easy to migrate a project initially started as Xamarin.Android but it turned out to require the creation of a new project and to move the code to the new project which we cannot afford in the present moment and which forces us to support only Android for our current release scope .