Greg Shackles Cross-platform mobile development with c# 

About Me Greg Shackles Senior Software Engineer OLO Online Ordering email [email protected] twitter @gshackles github github.com/gshackles blog gregshackles.com Slides speakerdeck.com/u/gshackles 

nycmobiledev.net @NYCMobileDev 

the Book oreil.ly/Lp5smR Discount Code: AUTHD Print Book: 40% Off E-Book: 50% Off 

Market Share (US): August 2012 Google Apple RIM Microsoft Symbian 52.6% Android 34.3% Apple 8.3% RIM 3.6% Microsoft Source: comScore 

native platform Languages Objective-C Java C# 

Write once, run anywhere 

"The biggest mistake we made as a company was betting too much on HTML5 instead of native." - Mark Zuckerberg 

Embrace the differences != != 

c# Everywhere MonoTouch Mono for Android Native 

The Power of C# •Base Class Library •LINQ •Parallel LINQ •Memory Management •Task Parallel Library •Dynamic •Skill Reuse 

xamarin Tools •Access to full platform SDKs •100% Native •Linker •Debugging •frequent releases •active community •Improved API 

C# CFStringRef  keys[]  =  {        kCTFontAttributeName,        kCTForegroundColorAttributeName };   CFTypeRef  bval[]  =  {        cfListLineCTFontRef,        CGColorGetConstantColor(kCGColorBlack) };   attr  =  CFDictionaryCreate  (        kCFAllocatorDefault,        (const  void  **)  &keys,  (const  void  **)  &bval,        sizeof(keys)  /  sizeof(keys[0]),  &kCFTypeDictionaryKeyCallBacks,        &kCFTypeDictionaryValueCallBacks);   astr  =  CFAttributedStringCreate( kCFAllocatorDefault,  CFSTR("Hello  World"),  attr); obj-c var  attr  =  new  CFStringAttributes  {        Font  =  listLineCTFont,        ForegroundColor  =  UIColor.Black.CGColor };   var  astr  =  new  NSAttributedString  ("Hello  World",  attrs); 

C#             findViewById(R.id.button).setOnClickListener( new  View.OnClickListener()          {              @Override      public  void  onClick(View  v)      {              //  handle  click      }        } ); Java [Activity(Label="@string/AppName",  MainLauncher=true)] FindViewById(Resource.Id.Button).Click  +=  delegate   {   //  handle  click }; 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - UI and Platform Code Shared Code 

What code can be shared? * with some limitations •Most non-UI or platform code •Core application logic •Entities •LINQ (objects, XML) •Network access •File / Database Access * 

sharing techniques •File Linking •Abstraction •Observer Pattern •Partial Classes and Methods •Conditional Compilation •portable class libraries 

library: xamarin.mobile Supports iOS, Android and Windows Phone xamarin.com/mobileapi 

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Case Study: iCircuit 

http://praeclarum.org/post/31799384896/icircuit-code-reuse-the-fourth-edition 16% 84% Shared Platform 31% 69% 13% 87% iOS WP7 Mac 19% 81% Android Case Study: iCircuit 

Case Study: TouchDraw 

http://lipsky.me/2012/9/11/touchdraw-code-reuse-updated 39% 61% Shared Platform 24% 76% 28% 72% iOS Mac Android Case Study: TouchDraw 

SignalR Client Libraries http://github.com/gshackles/SignalR C# To Go Mono.CSharp http://github.com/gshackles/CSharpToGo Case Study: Class Libraries 

Questions?