iP* programming tip #3

Today I will cover the necessary files of an iP* application and the folders that potentially hold data on the device from your application.

• .app folder holds everything without required hierarchy
• .lproj language support
• Executable
• Info.plist – XML property list holds product identifier > allows communicate with other apps and register with Springboard
• Icon.png (57x57) set UIPrerenderedIcon to true in Info.plist to not receive the gloss / shiny effect
• Default.png … should match game background; no “Please wait” sign ... smooth fade
  
• XIB (NIB) files precooked addressable user interface classes >remove NSMainNibFile key from Info.plist if you do not use it
• Your files; for example in demoq3/quake3.pak

If the game boots very fast a good mobile phone experience could be guaranteed by making a screenshot when the user ends the app and then using that screenshot while booting up the game and bringing it to the state it was before.
Every iP* app is sandboxed. That means that only certain folders, network resources and hardware can be accessed. Here is a list of folders that might be affected by your application:

• Preferences files are in var/mobile/Library/Preferences based on the product identifier (e.g. com.engel.Quake.plist); updated when you use something like NSUserDefaults to add persistance to game data like save and load
  
• App plug-in /System/Library (not available)
• Documents in /Documents
• Each app has a tmp folder
• Sandbox spec e.g. in /usr/share/sandbox > don’t touch 
  

The sandbox paradigm is also responsible for a mechanism that stops your game if it eats up too many resources of the iPhone. I wonder under which conditions this is going to happen.