为什么XCode吓坏了？ 也就是说，Xcode表示方法和属性不存在，但它们确实存在！

Question

XCode has been acting really, really strange recently. It is telling me that various classes' methods and properties do not exist - but they do! This is happening both with a custom class, and a Core Data class. I have declared all of the methods and properties, including all the necessary @synthesize calls, and have predeclared the classes using @class in the files which use them and included the .h files, but when I try to access the methods & properties - it throws errors or warnings, along the lines "No '+newMatrix' method found", "'Collection' may not respond to '+newMatrix'", and "Request for member 'isLanguage' in something not a structure or a union." These have all be declared properly - what could be causing XCode to choke?

Answer 1

Check whether they are in the list of files being compiled. You might not have added the files.

For Core data did you include the Framework?

Answer 2

Make sure you're using the right import statements - these two are very different:

#import <SDKLibrary.h>
#import "CustomClass.h"