This document summarizes the key aspects of developing mobile applications for the iPhone using Objective-C if you are a .NET developer familiar with C#. It outlines the hardware, software, and books required, compares the Objective-C and C# languages and Xcode and Visual Studio IDEs, demonstrates sample code, and discusses both the pleasures and pains of iPhone development compared to .NET. It also notes areas still lacking on the iPhone platform like dependency injection and ORM frameworks.

1. Mobile ‘i’ for the .NET Guy
iPhone development for .NET developer
Tuesday May 5th, 2009
© ThoughtWorks 2009

2. Agenda
• Introduction
• What do you need?
• Comparisons
• Code Demo
• Pleasure & Pain
• MIA
• Why?
• Open discussion
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3. Introduction
• .NET developer since 2004 (WinForms, WebForms,
ASP.NET MVC)
• C/C++ before that
• iPhone development since SDK beta 1
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4. What do you need?
Hardware
• Mac
• Mini - $599
• iMac - $1199
• MacBook - $1299
• MacBook Pro - $1999
• iPod Touch - $229 (8GB)
• iPhone 3G
• $199 (8GB + 2yr contract)
• $599 (8GB + no contract)
© ThoughtWorks 2009

5. What do you need?
Software
• iPhone SDK (require registration but free to download)
• iPhone Developer Program
• Personal - $99 (ad-hoc deploy to hardware, submit to AppStore)
• Enterprise - $299 (Personal + in-house deployment)
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6. What do you need?
Books
• The iPhone Developer Cookbook
• Beginning iPhone Development
• Beginning Xcode
• Programming in Objective-C 2.0
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7. What do you need?
Optional
Mockup Software
– Balsamiq (http://www.balsamiq.com/)
– iPhone Mockup (http://iphonemockup.lkmc.ch/)
Bucket loads of patience!
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8. Language Comparison
Objective-C C#
Square Brackets + Dot notation Dot notation
self.currentPostion = 0.5; this.currentPosition = 0.5;
[foodoStuffWith:bar]; foo.DoStuff(bar);
Named Parameter Object/Collection Initializer in C# 3.0
[foodoStuffWith:bar atPosition:4]; Named Parameter in C# 4.0
new foo(bar = “ISO”, position = 4);
Message Passing Method Invocation
Category Extension Method
Protocol/Interface Interface/Class
Class/Method prefix Namespace
C based (header file, pointers) Inline declaration, no pointer
Manual Memory Management (in iPhone) GC
NSString *foo = [NSStringalloc];
[foo release];
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9. IDE Comparison
quot;What is Xcode? It starts as a great source code editor...” and
quot;... and also has a nice debugger”
- Scott Forstall, Senior VP of iPhone Software
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10. IDE Comparison
Xcode 3.1 Visual Studio 2008
Text Editor
Refactoring
UI Design
Debugging
Profiling
Localization
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11. Code Demo
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12. Pleasure
• MVC architecture
• SDK’s API
o Hit the 80/20 rules
o Convention over Configuration
 Settings bundle
 Application icon
© JesperRønn-Jensen
• Simulator
o Work exactly as the real phone
o Except bandwidth, CPU (audio/video), interruptions
© ThoughtWorks 2009

13. Pleasure – cont’d
• Objective-C language features
o Dynamic
o Named parameters
o Categories
o Properties & @synthesize
o C-based. Lots of libraries available (e.g. libxml)
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14. Pain
• Xcode IDE
o CodeSense is not that smart
o Keyboard shortcuts are strange
o Take a while to re-train muscle memory
• Interface Builder © deeleea
o Good for simple UI, not so for complext UI
o Can’t do everything (UITabController and UINavigationController don’t
mix well)
• Objective-C syntax
o [foodoBar] – having to type the square brackets get old very quickly
o Header files – What’s this, the 90’s?
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15. Pain – cont’d
• Memory management
o Constraint environment
o No GC
o Have to remember to release object manually
• Debugging
o Do I really care about register address?
o Erratic behavior
• Unit testing framework
o OCUnit/Google Toolbox for mac
o OCMock
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16. Pain – cont’d
• Deployment
o Require code signing
o Opaque approval process
o Small(er) developer community
o StackOverflow
o Google’s your friend!
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17. MIA/WIP
• DI/IoC container
• OR/M
– Partly solved by SqlitePersistanceObjects (Google Code)
• Build Framework
– Use scripts (Rake, shell script)
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18. Why learn something so different?
• Diversify skills
• Expansive API
– A/V
– Graphics/Animation
– Game/Peer to Peer (in 3.0)
– Maps (in 3.0)
• On most CTOs’ radar
• iTuneAppStore
– Broad reach
– Easy to start
© ThoughtWorks 2009

19. Open Discussion ahung@thoughtworks.com
Twitter: AlexHung
http://alexhung.vox.com
Questions?
RubyCocoa
Mono
Feedback
© ThoughtWorks 2009