Secrets of an iPhone Developer

							Secrets of an iPhone Developer

                Brian Robbins
           Founder, Riptide Games
  Slides at http://www.dubane.com/cons/



   FITC Mobile – September 14, 2009
                                      Today
• Programming
       –   AudioSession
       –   Accelerometer Input
       –   Accelerometer Calibration
       –   Prevent screen darkening
       –   OS 3.0/2.0 compatibility
       –   Anti-Hacking
       –   NSZombieEnabled
       –   Xcode 3.2 Errors / Warnings
       –   Xcode 3.2 Static Analyzer
       –   Demo
• App Development
       –   Provisioning Profile tips
       –   iTunes Connect
       –   App Submission Tips
       –   Analytics tracking
       –   Score / Networking Tools
       –   iPhone Configuration Utility (iPCU)
       –   Other Useful Tools
Sept 14, 2009                                    Brian Robbins - slides available: http://www.dubane.com/cons/
                      Today’s Goal

                Most useful session you attend




Sept 14, 2009                  Brian Robbins - slides available: http://www.dubane.com/cons/
Programming
                      AudioSession
• Can use AudioSession APIs
       – C-based
• Or AVAudioSession (SDK 3.0)
       – Obj-C wrapper into same C calls
• Categories:
       – Ambient – Games, allows background iPod Music
         Playback and follows ringer switch
       – SoloAmbient – Same as ambient, but stops iPod Music
         Playback so use this if you have your own background
         music
       – Playback – Use for audio playback apps
       – Record & PlayAndRecord – For recording and playback

Sept 14, 2009                      Brian Robbins - slides available: http://www.dubane.com/cons/
                 Accelerometer Input
• Use an adaptive Low-Pass filter, for better response
• Full Implementation in the AccelerometerGraph sample application
#define FILTERFACTOR    0.1
#define ATTENUATION     3.0
#define MINSTEP         0.02


// Start with the value from a basic low-pass filter
basevalue = (newAcceleration * FILTERFACTOR) + (previousValue * (1.0 - FILTERFACTOR));
// Smooth more for small movement to filter out
noised = Clamp(ABS(Normalize(basevalue)-Normalize(newAcceleration))/MINSTEP - 1., 0.,
     1.);
// Calculate a proportional factor
alpha = (1.-d) * FILTERFACTOR / ATTENUATION + d * FILTERFACTOR;
// Use the new factor to offset smoothed values
value = newAcceleration * alpha + basevalue * (1. - alpha);




Sept 14, 2009                               Brian Robbins - slides available: http://www.dubane.com/cons/
                Accelerometer Calibration
• Map to the user’s starting orientation when
  doing heavy accelerometer control
• Do this when action starts, and ideally tell the
  user

• Sorry (James) no example



Sept 14, 2009               Brian Robbins - slides available: http://www.dubane.com/cons/
                Prevent Screen Darkening
• Turn on during gameplay
• Turn off in menus
[UIApplication sharedApplication].idleTimerDisabled = YES;




Sept 14, 2009                                  Brian Robbins - slides available: http://www.dubane.com/cons/
                OS 3.0 / 2.0 compatibility
• Use OS 3.0 features like MPMusicPicker,
  without requiring OS 3.0
       – Why? OS upgrades on iPod Touch is very low
• 4 technical steps
• Business rules for behavior




Sept 14, 2009                 Brian Robbins - slides available: http://www.dubane.com/cons/
                OS 3.0 / 2.0 Compatibility
1. Target > Info > General
      – Set Framework Linked Library from “Required” to
        “Weak”
2. Target > Info > Build
      – Set Base SDK to latest SDK (ie 3.0)
3. Target > Info > Build
      – Set iPhone OS Deployment Target to oldest SDK (ie
        2.1)
4. Check for availability of class before using it
      – if ([MPMusicPickerController])
Sept 14, 2009                   Brian Robbins - slides available: http://www.dubane.com/cons/
                             Anti-Hacking
• http://thwart-ipa-cracks.blogspot.com/
• Very simple detection, can go a lot more
  complex
NSBundle *bundle = [NSBundle mainBundle];
NSDictionary *info = [bundle infoDictionary];
if ([info objectForKey: @"SignerIdentity"] != nil)
{
      /* do something */
}


• Can also look to see if app is encrypted, check
  size of info.plist, call home, etc.
Sept 14, 2009                                    Brian Robbins - slides available: http://www.dubane.com/cons/
                NSZombieEnabled
• Executables > Info > Arguments
       – NSZombieEnabled value YES
• Good for EXC_BAD_ACCESS
• BAD for memory!!!




Sept 14, 2009               Brian Robbins - slides available: http://www.dubane.com/cons/
           Xcode 3.2 Errors & Warnings
• Use the tabs to see from last build or all builds
• Can also group by type instead of by class




Sept 14, 2009             Brian Robbins - slides available: http://www.dubane.com/cons/
                Xcode 3.2 Static Analyzer
• Uses Open Source Clang analyzer
• Good for memory references and Obj-C
  coding compliance
• Freaking awesome!




Sept 14, 2009               Brian Robbins - slides available: http://www.dubane.com/cons/
                Live Demo


Sept 14, 2009       Brian Robbins - slides available: http://www.dubane.com/cons/
App Development
                Provisioning Profile Tips
• Make and use a single “wildcard” App ID
       – Nothing but a single *
       – Use that for all development and provisioning
         profiles
       – Unless you’re doing in-app purchase or Push
         Notification
• When adding devices or users make a new
  Provisioning Profile
       – ie Riptide_Dev_01, Riptide_Dev_02

Sept 14, 2009                  Brian Robbins - slides available: http://www.dubane.com/cons/
                          iTunes Connect
• Release Date
       – When submit, set it to whatever, probably 1-2
         weeks in the future
       – The moment you get approval set the release
         date to today
       – For Updates, leave release date as is when submit
                • Setting to future will remove you from store!
       – Moment approved, set release date to today


Sept 14, 2009                             Brian Robbins - slides available: http://www.dubane.com/cons/
     iTunes Connect App Submission
• Taking ~2 weeks for approval
       – Every time, even if rejected for app description
         problem!
• Plan for keywords, but don’t use competitor
  names
• Don’t put pricing in your app description
• Don’t put keywords in your app title


Sept 14, 2009                   Brian Robbins - slides available: http://www.dubane.com/cons/
                Analytics Tracking
• Simple, cheap (free) and very easy to
  implement
• PinchMedia is good
• Other major one is Flurry Analytics
• Not something you need to pay for!




Sept 14, 2009            Brian Robbins - slides available: http://www.dubane.com/cons/
                Score / Networking
• Good idea, especially for games
• Use an existing network to borrow
  traffic/users
• OpenFeint, ScoreLoop are biggest open ones
• Plus+ from ngMoCo is picking up steam, but
  you have to talk to ngMoCo to use it.



Sept 14, 2009            Brian Robbins - slides available: http://www.dubane.com/cons/
            iPhone Configuration Utility
• Search for iPhone Configuration Utility on
  Apple Site (2.1 latest version)
• Basically the Xcode Organizer without Xcode
• Much easier for AdHoc users to install and
  manage apps




Sept 14, 2009             Brian Robbins - slides available: http://www.dubane.com/cons/
                Other Useful Tools
• MajicRank
       – http://www.majicjungle.com/majicrank.html
• AppViz
       – http://www.ideaswarm.com/
• MobClix for rank tracking
       – http://www.mobclix.com/appstore/1
• AppShopper for price history
       – http://appshopper.com/

Sept 14, 2009                 Brian Robbins - slides available: http://www.dubane.com/cons/
                                         Recap
• Programming
       –   AudioSession
       –   Accelerometer Input
       –   Accelerometer Calibration
       –   Prevent screen darkening
       –   OS 3.0/2.0 compatibility
       –   Anti-Hacking
       –   NSZombieEnabled
       –   Xcode 3.2 Errors / Warnings
       –   Xcode 3.2 Static Analyzer
       –   Demo
• App Development
       –   Provisioning Profile tips
       –   iTunes Connect
       –   App Submission Tips
       –   Analytics tracking
       –   Score / Networking Tools
       –   iPhone Configuration Utility (iPCU)
       –   Other Useful Tools
Sept 14, 2009                                    Brian Robbins - slides available: http://www.dubane.com/cons/
  Questions?
Slides at http://www.dubane.com/cons/



           Brian Robbins
      www.riptidegames.com
         Twitter: @dubane
     brian@riptidegames.com