Xcode 6: Adding Existing Classes Produce Compilation Error

Question

I've just installed Xcode 6 and I've found that .. whenever I try to add an existing file to the project it produce a compilation error in the basic UIKit classes such as UITableView and NSObject ..

I have no idea why this is happening!

Answer 1

根据Shai和iDev的回答，我发现在xcode 6中没有默认的PCH文件..因此，uikit和Foundation没有默认的导入..应该手动添加。