iPhone/iPad开发扎记 2012/02/11 － 玩转iOS Audio Service

### 主要任务：玩转xcode document中所有audio samples ### 

1. sysSound 

Q: Why uses iPad by default ?

Q: what's the reason for the following statement ? 

    // Store the URL as a CFURLRef instance

    self.soundFileURLRef = (CFURLRef) [tapSoundretain];

   A: required by AudioServiceCreateSystemSoundId(...)

Q: sound file's position matters ?

Q: why sound still works after renaming the sound file name ?

2. avTouch

Crash when pressing "play" button as follows: 

(gdb) continue

LLVM ERROR: Cannot yet select: 0x7014fd8: v16i8 = bit_convert 0x701ba48 [ORD=246] [ID=170]

  0x701ba48: v8i16 = X86ISD::PSHUFLW 0x701b828, 0x701b608 [ID=166]

    0x701b828: v8i16 = X86ISD::PSHUFHW 0x7014db8, 0x701b608 [ID=162]

      0x7014db8: v8i16 = llvm.x86.sse2.packssdw.128 0x7014d30, 0x7014ca8, 0x7014c20 [ORD=243] [ID=158

see here : http://stackoverflow.com/questions/5339470/llvm-error-cannot-yet-select-error

It may has something to do with SDK version. xcode 3.2.4/SDK4.1 might fix this issue. ( current is xcode 3.2.6/SDK4.3 )

Q：存盘后，不知为何突然无法执行了，没有选simulator/device的选项了？

3. download xcode 4.x 

my apple programmer id: xuejunzou@gmail.com

不成功：

本机ＯＳ：MAC OS X 10.6.8 ( xcode 4.x requires 10.7+ )

4. task: to change the simulator version for  a specific project ?

Q: where is the following folder ?

~/Library/Application Support/iOS Simulator

tip: Simulator程序可以模拟不同版本的模拟器，程序放在不同目录里的。