1. iPhone Development for
Experienced Web Developers
SXSW 2009

2. Who We Are
• Joshua Siler, VP of Technology
• Jordan Lev, Senior Developer
http://www.bnj.com
(Relationship Marketing Agency)
A few of our clients:

3. Poll
How many people here have
tried native iPhone app
development?

4. Poll
How many people here have
an online application that
might use an iPhone client?

5. Session Overview
• Web developer POV
• What’s different about iPhone dev
• Our project, some design decisions
• Code review and mini-tutorial

6. What’s Different

7. Web Developers…
are mad for POWER

8. iPhoneProcessor
• ~400mhz
processor, 128mb
RAM
• 10 to 100 times
slower processor
and memory
• Premature
optimization takes
on a different
meaning
*
http://www.primatelabs.ca/blog/2007/08/gee

9. Web Latency

10. Web Latency

11. Web Latency

12. Web Latency

13. Web Latency

14. iPhone Latency

15. Latency Management
• Take latency into account during app design
• Asynchronous operations where anything
takes any kind of time
• Explicitly define wait indicators
• Multithreaded considerations

16. Tools
• Must have an Intel powered Mac
• $99 to join Apple Developer Program
• Free SDK download, Xcode, Objective C, Cocoa
• http://developer.apple.com

17. TIOBE Programming Community Index

18. TIOBE Programming Community Index

19. Objective C
• C with OO added
• Totally different than typical Web Languages
– Pointers
– Memory Management
• No garbage collection
– Non-linear code execution
– Syntactical… saltiness?
• Language features seem years behind
• Biggest burden to new non-Mac developers

20. Xcode

21. Cocoa
• Objective C all low level
• Cocoa is really great

22. Coming Soon

23. Our Project

24. CP Screenshot

25. Protocols
• https for secure data transfer
• Username and password authenticated
• REST web services interface
• JSON for returning data

26. Web Services SOAP (google)
<?xml version=quot;1.0quot; encoding=quot;UTF-8quot;?>
<SOAP-ENV:Envelope
SOAP-ENV:encodingStyle=quot;http://schemas.xmlsoap.org/soap/encoding/quot;
xmlns:SOAP-ENC=quot;http://schemas.xmlsoap.org/soap/encoding/quot;
xmlns:xsi=quot;http://www.w3.org/1999/XMLSchema-instancequot;
xmlns:SOAP-ENV=quot;http://schemas.xmlsoap.org/soap/envelope/quot;
xmlns:xsd=quot;http://www.w3.org/1999/XMLSchemaquot;
>
<SOAP-ENV:Header>
<developer_emailxsi:type=quot;xsd:stringquot; SOAP-ENC:root=quot;1quot;>INSERT_DEVELOPER_EMAIL_HERE</developer_email>
<display_localexsi:type=quot;xsd:stringquot; SOAP-ENC:root=quot;1quot;>en_US</display_locale>
<developer_passwordxsi:type=quot;xsd:stringquot; SOAP-ENC:root=quot;1quot;>INSERT_PASSWORD_HERE</developer_password>
</SOAP-ENV:Header>
<SOAP-ENV:Body>
<ns1:associateAccount xmlns:ns1=quot;http://www.google.com/api/adsense/v3quot; SOAP-ENC:root=quot;1quot;>
<loginEmail>INSERT_PUBLISHER_EMAIL_HERE</loginEmail>
<postalCode>12345</postalCode>
<phone xsi:nil=quot;1quot;/>
<developerUrl>INSERT_DEVELOPER_URL_HERE</developerUrl>
</ns1:associateAccount>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>

27. Web Services REST (amazon)
http://rcm.amazon.com/e/cm?t=[Associates ID goes here]
&l=st1&search=[subject keyword goes here]
&mode=[product line goes here]
&p=102&o=1&f=xml

28. Web Services
• Lightweight approach for mobile is critical
• REST interfaces far more efficient
• JSON for returned data
– Allows you to serialize objects with known data and
types
– Can be 100x faster to parse than XML
– Significantly fewer control characters and other
overhead
– Platform independent, easy to consume
– http://www.json.org

29. Architecture Diagram Web
https; GET websites
Retrieve List of Provide List of
JSON result, [[name,id]…]
Projects Websites
Auth
https; GET websites?id=
Provide Data for
Retrieve Data for
JSON result, [[key,value]…] Website
Project
Edit/Enter
Username and
Password
Local Storage

30. App Demo and Mini-Tutorial

31. Concepts
• MVC
• Events and Delegates
• Interface Builder

33. Lay of the Land
• AppDelegate
– (initialization)
• ViewController
– (one per page)
• + XIB
• Data Models

34. Pseudocode
Screen loads
• Controller asks model for data
• Make http request
• Parse JSON (convert it to objects)
• Display data
• Wait for additional events (e.g. button click):
repeat process with new page

35. Pseudocode
Screen loads
Controller asks model for data
• Make http request
• Parse JSON (convert it to objects)
• Display data
• Wait for additional events (e.g. button click):
repeat process with new page

36. Pseudocode
Screen loads
Controller asks model for data
Make http request
• Parse JSON (convert it to objects)
• Display data
• Wait for additional events (e.g. button click):
repeat process with new page

37. Pseudocode
Screen loads
Controller asks model for data
Make http request
Parse JSON (convert it to objects)
• Display data
• Wait for additional events (e.g. button click):
repeat process with new page

38. Pseudocode
Screen loads
Controller asks model for data
Make http request
Parse JSON (convert it to objects)
Display data
• Wait for additional events (e.g. button click):
repeat process with new page

39. Pseudocode
Screen loads
Controller asks model for data
Make http request
Parse JSON (convert it to objects)
Display data
Wait for additional events (e.g. button click):
repeat process with new page

40. Memory Management
• Golden Rule
– If you alloc/init it, you have to release it.
• If you’re returning it from a method, autorelease it.
– If you’re NOT alloc/init’ing it, do NOT release it!
• Mostly…
• Finding leaks
– Use “Instruments” application.

42. Compiling, Testing, Distributing
• Apple developer account required to deploy
to iPhone
• Simulator can be different than actual device
operation, be sure to QA thoroughly
• Be prepared for a lengthy process of
registering, signing, deploying and obtaining
approval for your app

43. What We Think

44. Really Like about iPhone Development
• Incomparable/exciting platform
• Standardized hardware, relatively powerful
device
• Cocoa and MVC paradigm
• “Bare metal” programming is a refreshing
change of pace

45. Really Don’t’ Like
• Objective C, iPhone application model
– Lots of assumed knowledge and undocumented rules
to discover
– Refactoring is difficult
• Xcode
– Code editor with GCC config… have come to expect
more
• App deployment
• Flaky connectivity
• Apple controlled domain

46. Q&A