This document discusses cross-platform localization for mobile apps using .NET. It introduces Xamarin, a tool that allows developers to write native mobile apps for Android and iOS using C# and shared code bases. It also discusses the Multilingual App Toolkit, which helps manage localized string resources across platforms. Localization involves translating text, images, and other resources to support multiple languages and locales. The document provides tips on effective localization strategies and managing localized resources in Xamarin, Xamarin.Forms, Android and iOS apps.

1. Cross-Platform Localization for Mobile Apps Using .NET
Chris Miller, Tyler Technologies
James Montemagno, Xamarin
May 15th, 2015
May 14 – 15, 2015
2015
Microsoft
MVP Virtual
Conference

2. Who we are : Chris Miller
Chris is a Senior R&D Engineer for Tyler Technologies,
Currently working on mobile apps for the K-12
transportation market. He leads the Tech Valley .NET
User Group in Albany, NY.
@anotherlab
http://www.rajapet.com

3. Who we are: James Montemagno
James Montemagno is a Developer Evangelist at
Xamarin. He has been a .NET developer for over a
decade working in a wide range of industries including
game development, printer software, and web services.
Previously, James was a professional mobile developer
on the Xamarin platform for over 3 years, with several
published apps on iOS, Android, and Windows.
@JamesMontemagno
http://motzcod.es/

4. What is localization?
Localization is the process that you follow to allow your web site or
application to support multiple languages and locales.

5. Why should you localize your app?
• Greater Exposure
• Easy Deployment
• Business or Legal requirements

6. Why should you localize your app?

7. Why should you localize your app?

8. Why should you localize your app?

9. Why should you localize your app?

10. Know the localization problem
• What are the localization requirements for your app?
• How many languages do you need to support?
• Do you need to use right-to-left languages like Arabic or
Hebrew?
• Does your application have it's own or an industry specific set of
terminology?

11. Common terminology
Locale - The culture for the user
Language - The language used by the user. The same language in
different countries can have different spelling and grammar rules.
Culture/UICulture - The .NET representation of a locale. Culture is
the locale, UICulture the language.

12. Example Images
Stop Sign (USA) Stop Sign (France)

13. Example Images
• Stop Sign (Japan)

14. Gender
• English is usually gender neutral, other languages are not.

15. Plural Forms
• The common pattern in English is the singular/plural form
• Asian languages typically use just a single from
• French and Brazilian Portuguese use a different singular/plural
form.
• Then it gets complicated. See https://developer.mozilla.org/en-
US/docs/Mozilla/Localization/Localization_and_Plurals#List_of_Plu
ral_Rules for a long list of rules.
• Use the “Noun : Pattern” instead
• New Messages: 1

16. The tools that I use
• Visual Studio 2013/2015
• Xamarin (both on OS X and as a VS plugin)
• Multilingual App Toolkit (MAT)

17. Create native iOS, Android, Mac and
Windows apps in Visual Studio and C#
About Xamarin

18. Xamarin’s Unique Approach
• Native User Interface
• Native Performance
• Shared code across
platforms
• C# & .NET Framework
• Full API Coverage

19. Xamarin’s Unique Approach
With Xamarin.Forms:
more code-sharing, native controls

20. Xamarin
First
release of
Xamarin.Mac
Launch
Partner
Program
200,000
Developers
Xamarin
Founded
First release of
Xamarin.Android
Xamarin.iOS
launches (originally
known as
MonoTouch)
Ximian
Founded
Over a Decade of Enterprise Production Use
2001 2003 2009 2011 2012 2013
Mono
Launches
Ximian Acquired
by Novell
Xamarin 2.0
Component Store
Xamarin Test Cloud
Evolve 2013
Microsoft Partnership
500,000
Developers
100+ Partners
100+ Components
2014
//
Xamarin 3
2000
SAP Partnership
Fire TV Support
Salesforce partnership
Visionary in Gartner
Magic Quadrant
Google Glass Support
Visual Studio Partner
of the Year
Android Wear Support
Xamarin Evolve 2014
800,000
Developers
200+ Partners
200+ Components

21. Xamarin
• Provides a .NET development environment for C# and F# on iOS
and Android.
• Supports PCL libraries and shared projects.
• Compiles to native code and provides full access to native APIs.
• Xamarin.Forms provides an abstraction layer that lets you write
for that will compile and run as
• Has a plugin for Visual Studio and their own IDE called Xamarin
Studio for Windows and OS X.
• iOS development still requires an OS X machine for the
compilation and debugging.

22. Xamarin – Two Ways
• Xamarin.iOS and Xamarin.Android
• Xamarin.Forms

23. How to manage the language files
• Pick one application as the source for the string resources. This
works best for Xamarin.Forms applications. It can be done for
Xamarin.Android and Xamarin.iOS but requires some extra work
to generate the Android and iOS resource files from the Windows
RESX files.
• Have app specific sets of resource files and use tooling to
manage the language files.

24. Windows Store & Windows Phone
• We just need to create the .resx files for the locales to support
and let the .NET Runtime do the heavy lifting.
• Use the Multilingual App Toolkit in Visual Studio to manage the
resource files.

25. Xamarin.iOS
• Create the resource string files and put them in the proper
location.
• File should be named Localizable.strings and placed in a folders
for each language, with the folder name using the language code
+ .lproj. To localize the app name, set CFBundleDisplayName
in InfoPlist.strings
– en.lproj for English
– es.lproj for Spanish
• Prior to iOS 8, only the language code was supported. iOS 8
added support for locales.

26. Xamarin.iOS
• In Xamarin.iOS, we need to call LocalizedString, which maps to
iOS’s localizedStringForKey method to do the language look up.
• That’s too much work.
• Let’s add a string extension method to make it easy to use.

27. Xamarin.iOS string extension
A helper class for setting the translated text

28. Xamarin.iOS string extension
Some examples…

29. Xamarin.Android
Create the default resource files, plus additional resources for each
language supported. Strings, layouts, images, any resource can be
localized.
While you can create alternate layouts for more verbose languages
(e.g. German), this will make your app harder to maintain.

30. Converting RESX to iOS & Android
• iOS & Android use text files for string resources.
– iOS uses flat text file
– Android uses a XML format similar to RESX
• Use the same constants for each platform for shared resources.

31. We can convert this RESX file

32. To iOS/Android string resources
• iOS
• Android

33. Xamarin.Forms
• Single UI to target Android, iOS, and Windows Phone apps.
• Common set of controls that map to native controls at runtime.
• UI can be built from XAML markup or C# code.
• Can be mixed with Xamarin.iOS & Xamarin.Android.

34. Multilingual App Toolkit
• Is XLIFF based, an industry standard file format for resource
translations. Provides a basic audit trail of translated text values.
• Will make language specific versions of your string RESX files.
• Knows about Xamarin.iOS and Xamarin.Android and generates
their string resource files.
• Can machine translate resource files using Bing.
• Get it from https://dev.windows.com/en-us/develop/multilingual-
app-toolkit

35. Localization with Xamarin.Forms
• Not explicitly supported out of the box, but easy to implement.
• Xamarin has posted examples using RESX and Vernacular in their
forums.
• Works great with Multilingual App Toolkit

36. Multilingual App Toolkit
• Enable MAT for the project from the Tools menu
• Right-click on the project and select “Add translation languages…”

37. Multilingual App Toolkit
• Double-click on a XLIFF to edit it

38. Multilingual App Toolkit
• Right-click on a project to machine translate the XLF files

39. Localization with Xamarin.Forms
• Move the AppResources.resx from Windows Phone project to
shared PCL or create a new one in the PCL
• Create the localized versions of the RESX file with MAT
• Create an IMarkupExtension to do translations in the XAML

40. Getting the localized text in XAML
• Add your namespace
• Use the databinding to call the markup converter

41. Getting the localized text in code behind
• Just reference the resource file and resource id string

42. Right to Left (RTL) Support
• Target Android 4.2 or later.
– add android:supportsRtl="true" to the <application> element in
your manifest file
– Change all of your app's "left/right" layout properties to new
"start/end" equivalents
• iOS uses the Unicode Implicit Direction Mark Right-To-Left mark
(#200F) to set RTL in the UILabel control as a string prefix.
• Windows Phone uses FlowControl property, set automatically by
current culture.
• Xamarin.Forms does not have explicit support for RTL, it has to be
done manually.

43. Demo Time

44. General Tips
• Do one platform a time and using tooling to transform the
language resource files to the other platforms.
• Only do the languages that you need to do.
• Use a fake language to test coverage and layout. Scott
Hanselman has a tool to create a fake language.
(http://www.hanselman.com/blog/PsuedoInternationalizationAnd
YourASPNETApplication.aspx)
• Multilingual App Toolkit also generates a pseudo language.

45. General Tips
• To test different languages, set CurrentCulture and
CurrentUICulture in code.
• If you change the language on the device, use an emulator. It’s
not always easy to set the language back to your native choice.
• Language not showing up for Windows Phone? Make sure it’s
checked of under Supported Cultures
• To localize the app & tile title for Windows Phone you need to
create a separate resource dll. See
https://msdn.microsoft.com/library/windows/apps/ff967550%28v
=vs.105%29.aspx
• To localize the launcher name in Android, you will need to use
strings.xml in Resourcesvalues-xx-XX

46. General Tips
• Send the RESX or XLF to a commercial translation service.
• Hire someone to translate the resource files. Make sure that they
understand the domain and industry standard terms.
• If you can't afford a paid translation, Bing translate basic
terminology and crowd source it. Remember, you get what you
pay for.

47. General Tips
• If you are using 3rd party components, make sure that they can
be localized.
• Make sure to translate App Store text.

48. Thank You! …Questions?
The sample code from this presentation can be found on
https://github.com/anotherlab/TheDoctors
Chris Miller can be reached via
@anotherlab
http://www.rajapet.com
James Montemagno can be reached via
@JamesMontemagno
http://motzcod.es/

49. Resources - Platform
• Android
http://developer.android.com/guide/topics/resources/localization.
html
• Apple
https://developer.apple.com/internationalization/
• Windows Phone
http://msdn.microsoft.com/en-
us/library/windowsphone/develop/ff637522(v=vs.105).aspx
• Windows Store
http://msdn.microsoft.com/en-
us/library/windows/apps/hh710212.aspx

50. Resources
• Xamarin
http://xamarin.com/
• Vernacular
https://github.com/rdio/vernacular
• Third Party Localization Vendors
https://developer.apple.com/internationalization/#vendors
• Some information about XLIFF
http://info.moravia.com/blog/bid/354057/What-s-So-Sexy-
About-XLIFF-2-0

51. Resources - Multilingual App Toolkit
• Blog
http://blogs.msdn.com/b/matdev/
• User Voice
http://multilingualapptoolkit.uservoice.com/
• Installation
https://dev.windows.com/en-us/develop/multilingual-app-toolkit