Missing Frameworks/Xcode Upgrade?

So I'm getting problems when trying to make in iPhone app in Xcode (version 3.1.4)... I'm trying to use the ExternalAccessory Framework but it didn't exist in my System/Library ... /Frameworks directory. Is there any way to get it or a place to download it? I tried to upgrade to Xcode 4 but I was unsure of how to transfer my old projects to there and after much frus开发者_开发百科tration ended up just staying with the only version, perhaps I should try again?

Having run into the same problem with XCode 4.3.3 I bit the bullet and installed XCode 4.5. Fortunately my project wasn't broken by the upgrade (as has been the case in the past) and the ExternalAccessory library is now available.

In the project navigator, select your project Select your target Select the 'Build Phases' tab Open 'Link Binaries With Libraries' expander Click the '+' button Select your framework