Should I choose Xamarin native or Xamarin.Forms for existing Android app?

Question

We have an android application and want to recreate it for cross platform.

What are the facts for or against Xamarin native and forms?

The advantage of native would be, we could reuse all the xml-layouts while we have to recreate the iOS view in either XAML or XIB?

Is there anything what is really a blocker?

Answer 1

I'll comment based on Giorgi's answer with some actual insight and refer to the copied bullet points:

This is a resume of the experience i've gathered in the past 6 months:

Xamarin.Forms is best for:

• Apps that require little platform-specific functionality
  • Wrong. With DI you can use any device functionality you could possibly want. Check out XLabs on GitHub if you doubt this.
• Apps where code sharing is more important than custom UI
  • Kind of nonsense really. You can write your own renderers to represent controls of each platform in the way you want. I've also written more difficult renderers for custom controls such as a SideDrawer. In android i was done in 2 days, iOS about 2 weeks (android renderer was just a wrapper for the native control)
• Developers comfortable with XAML
  • well yeah and anyone who enjoys convenient UI development. Mind you that there is a learning curve with xaml (which i already knew at the time i started from WPF development). But from what i have seen it's not that different from android.

Xamarin.iOS & Xamarin.Android are best for:

• Apps with interactions that require native behavior
  • While hacking your solution up natively is certainly faster you can instead be done rather quick if purchase good controls / know a good native implementation and mirror it in C#, since the API in C# is very similar to the native one.
• Apps that use many platform-specific APIs
  • Not sure why Xamarin is doing anti advertisement against forms. I had little trouble with it so far
• Apps where custom UI is more important than code sharing
  • Probably true, but it's also harder to keep UI functionality inline and you will need more manpower.

Things to consider about forms:

• Forms seems to be stabilizing at the moment and i am sure Microsoft will do their best to turn it into a solid, reliable product (build issues have been a nightmare in the past sometimes, but it has gotten better over time)

• The XAML for Xamarin is less developed compared to WPF XAML, though very similar. Recent nuget updates however provide mirrored functionality at an impressive rate. The vast majority of features you expect and love about XAML are present.

• List performance is bad if you don't do your research (here). Performance increased loads in that area.

• If i had to make the choice again i'd still go for forms. While there are sometimes things which seem flawed / bad you can usually figure out a clean fix somehow, while spending most of your time actually developing the app. (sometimes you will still find things which just make you frown why something isn't implemented, like the Margin property being implemented only just after microsoft purchased xamarin)

• If you end up having a requirement of nested lists, make sure to have a look at embeded native controls in order to achieve the maximum performance - this was essential for a product i was working at. See this

Answer 2

According to Xamarin.Forms main page:

Xamarin.Forms is best for:

Apps that require little platform-specific functionality
Apps where code sharing is more important than custom UI
Developers comfortable with XAML

Xamarin.iOS & Xamarin.Android are best for:

Apps with interactions that require native behavior
Apps that use many platform-specific APIs
Apps where custom UI is more important than code sharing

Answer 3

Giorgis answer is the right one, but since you added some more constraints here are my thoughts.

I would analyze the current app. How much code is business logic which can be shared? How customized is the UI, should it look more native or more the same and how will it change in the future? If you plan to change a lot in UI and platforms should look similar, it might be easier to switch to forms.

Also consider if are you planning to develop for Windows Phone? If yes, you might save a lot of time just for this third platform.

After all there is one thing which I would also keep in mind. Developing in Xamarin.Forms does not mean, you cannot develop native. It is just an additional framework. In worst case you can still do everything natively.

Answer 4

Personally I use Xamarin.iOS & Xamarin.Android with MvvmCross, that way I can keep full control of the native UI on each platform while maximizing code reuse.

Answer 5

From Xamarin website (who knows better than them?):

Xamarin.Forms is best for: Data entry apps Prototypes and proofs-of-concept Apps that require little platform-specific functionality Apps where code sharing is more important than custom UI

[https://developer.xamarin.com/guides/xamarin-forms/]

With Xamarin.Forms at runtime, each page and its controls are mapped to platform-specific native user interface elements. With Native Xamarin.Android and Xamarin.iOS apps leverage platform-specific hardware acceleration, and are compiled for native performance. This can’t be achieved with solutions that interpret code at runtime.

"Xamarin.iOS - The best way to build native iOS apps."

• Ship native app bundles on the App Store. Our Ahead-of-Time (AOT) compiler compiles Xamarin.iOS apps directly to native ARM assembly code, meaning your app is a native platform binary.
• Access any iOS API. We bring 100% of Apple’s iOS SDK to C#, enhancing Objective-C APIs with stronger types and .NET naming conventions so you feel right at home.
• Call existing Objective-C code from C#. Use your existing Objective-C code, frameworks, and custom controls in your Xamarin app using our automatic binding generator.
• Build WatchKit apps. Use Xamarin Studio or Visual Studio to build new Watch Apps, edit Watch user interfaces in the iOS Designer, and debug Watch apps in the iOS Simulator.
• Stay up-to-date with Apple. We released same-day support for iOS 5, iOS 6, iOS 7, and iOS 8 so your apps can take advantage of the latest iOS features as soon as possible.

[https://www.xamarin.com/platform]

"Xamarin.Android - The best way to build native Android apps."

• Ship native Android packages. Xamarin.Android uses just-in-time compilation for sophisticated runtime optimization of your app’s performance, meaning your app is a native Android APK.
• Access any Android API, including new form factors. We bring 100% of Google’s Android APIs to C#, enhancing Java APIs with async support and .NET naming conventions so you feel right at home.
• Call existing Java code from C#. Use your existing Java code, frameworks, and custom controls in your Xamarin app using our automatic binding generator.
• Build Android Wear apps. With access to 100% API support for Android Wear, create full-featured applications capable of running on Android Wear devices. Stay up-to-date with Android. Xamarin stays up-to-date with the most current APIs from Google, so you can always use the latest features in your apps.

[https://www.xamarin.com/platform]