Xcode iPhone - 添加框架有点工作

No biggie, but when I add the AVFoundation framework for the iPhone, it turns red for some reason I'm unable to figure out why. The project will not compile unless I add this framework, and if I do, Xcode will mark the framework red (apparently that means xcode cannot find the framework), but yet it will work.No biggie, but when I add the AVFoundation fram