If you've used iPhone OS applications, you've no doubt seen a number of common tricks that are in no way obvious from looking at the documentation provided in the SDK. In this session, we'll look at a grab-bag of some of the most popular and least obvious techniques you'll want in your developer's toolkit.

1. HOW DO I DO THAT ON
IPHONE?
Chris Adamson
CodeMash 2010

2. AGENDA
Table tricks
Media mastery
Tsundere tools
Miscellania

3. TABLE TRICKS

4. SORTING TABLES WITH KVC

5. SORTING ARRAYS
NSSortDescriptor works nicely with key-value-coding
Values need to implement compare:
Alternatives
sortedArrayUsingSelector: - called on value
sortedArrayUsingFunction:context: - calls a C
function

6. CUSTOM TABLE CELLS

7. CUSTOM TABLE CELLS
Cell goes in its own nib, connected to an outlet in an
owner
Owner uses this outlet when creating new cells
Find subviews of cell by tag, or subclass
UITableViewCell and set up outlets and properties.

8. TABLE FILTERS

9. TABLE FILTERING
IB provides “Search Bar and
Search Display Controller”
UISearchBar and a UITable that
slides in to show filter results.
You implement
UISearchBarDelegate

10. TOO MUCH MORE!
Tweetie 2 - pull-to-reload
http://github.com/enormego/
EGOTableViewPullRefresh
http://www.drobnik.com/touch/2009/12/how-to-
make-a-pull-to-reload-tableview-just-like-tweetie-2/
Controls in tables - see Apple’s table guide

11. MEDIA MASTERY

12. VIBRATION IS A “SOUND”?

13. VIBRATION
AudioServicesPlaySystemSound
(kSystemSoundID_Vibrate);
Does nothing on iPod touch
AudioServicesPlayAlertSound with a SystemSoundID
may also vibrate, if user has vibrate-on-ring set

14. PLAYING NICE WITH IPOD

15. PLAYING NICE WITH IPOD
Use AVAudioSession categories to set behavior
AVAudioSessionCategoryAmbient
AVAudioSessionCategorySoloAmbient
AVAudioSessionCategoryPlayback
AVAudioSessionCategoryRecord
AVAudioSessionCategoryPlayAndRecord
AVAudioSessionCategoryAudioProcessing

16. PLAYING NICE WITH IPOD
Core Audio uses same categories, different names
kAudioSessionCategory_AmbientSound
kAudioSessionCategory_SoloAmbientSound
kAudioSessionCategory_MediaPlayback
kAudioSessionCategory_RecordAudio
kAudioSessionCategory_PlayAndRecord
kAudioSessionCategory_AudioProcessing

17. HANDLING INTERRUPTIONS

18. HANDLING INTERRUPTIONS
Can be from alarms, incoming calls, etc. If accepted,
your app terminates
AVAudioSessionDelegate beginInterruption,
endInterruption
Core Audio makes you set an interruption callback
when you InitializeAudioSession
App-level is different: applicationWillResignActive: and
applicationWillTerminate:

19. TSUNDERE TOOLS

20. “TSUNDERE” ( )

21. KEYCHAIN

22. KEYCHAIN ON IPHONE
No access to a system-wide keychain
Apps get access to their own items only (well…)
Four essential C functions:
SecItemAdd, SecItemDelete, SecItemUpdate,
SecItemCopyMatching
All are a huge hassle to call

23. KEYCHAIN FTW!
Keychain items survive application wipes and
reinstalls
Keychain is encrypted, and backed up by iTunes
Works with untyped void* data types
You can put whatever you like in a keychain item

24. KEYCHAIN FTW 2!
Can share data between applications with Keychain
Create Entitlements file with a keychain-access-group
that matches first fragment of your apps’ identifiers.
Use key kSecAttrAccessGroup in keychain calls
Use same signing credentials
That said… I couldn’t get this working in time

25. XCODE

26. BUILDING “LITE” VERSIONS

27. BUILDING “LITE” VERSIONS
Create multiple targets
Each target has different Info.plist and different build
settings
Potentially different Icon.png, MainWindow.xib, etc.
Can omit resource files from your lite version
Set OTHER_CFLAGS to do #ifdef

28. COMMAND-LINE BUILDS

29. COMMAND-LINE BUILDS
/usr/bin/xcodebuild builds project in current
directory with current settings.
Can build any or all targets, supports different SDKs
(iPhone 2.2 / 3.0 / 3.1), and configurations (Debug /
Release)
Only on Mac
Buy an XServe for your build farm

30. CREATING .CAF FILES

31. /USR/BIN/AFCONVERT
Reads and writes all default Core Audio formats
Useful for converting into .caf format (preferred
format for iPhone audio files) and transcoding (no
floating-point PCM samples on iPhone)
Getting the arguments right can be tough
afconvert -d LEI16 -f 'caff' orig-cymbal.caf

32. MISCELLANIA

33. HOW TO GET YOUR
NETWORK APP REJECTED

34. NETWORK REACHABILITY
Create SCNetworkReachabilityRef
Call SCNetworkReachabilityGetFlags with address
you intend to connect to
Call SCNetworkReachabilitySetCallback to get
callbacks when this value changes
Mask off the results

35. USEFUL REACHABILITY FLAGS
Good: kSCNetworkReachabilityFlagsReachable,
Probably OK:
kSCNetworkReachabilityFlagsConnectionRequired,
kSCNetworkReachabilityFlagsConnectionOnTraffic,
kSCNetworkReachabilityFlagsConnectionOnDemand
How to know you’re not on wi-fi:
kSCNetworkReachabilityFlagsIsWWAN

36. MAKE NETWORK FAST
URL Loading System quietly supports gzip and deflate
You just get the decoded data
NSMutableURLRequest *request = [NSMutableURLRequest
requestWithURL:postURL];
[request setHTTPMethod: @"POST"];
[request addValue:@"gzip"
forHTTPHeaderField:@"Accepts-Encoding"];

37. MORE…
Prepared exclusively for Chris Adamson

38. CONTACT
Me:
http://www.subfurther.com/
@invalidname
invalidname@gmail
iPhone SDK Development book
http://www.pragprog.com/