symbol(s) not found for architecture armv7s (linker command failed with exit code 1)

问题

When I build in Xcode 5 for IOS7 I get this error:

Undefined symbols for architecture armv7s:
  "_OBJC_CLASS_$_CIFilter", referenced from:
      objc-class-ref in UIImage+Filter.o
  "_kCIInputImageKey", referenced from:
      -[UIImage(Filter) filterWithPreset:] in UIImage+Filter.o
  "_OBJC_CLASS_$_CIImage", referenced from:
      objc-class-ref in UIImage+Filter.o
  "_OBJC_CLASS_$_CIContext", referenced from:
      objc-class-ref in UIImage+Filter.o
ld: symbol(s) not found for architecture armv7s
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I notice that the error goes away if I remove the UIImage+Filter.h/m file and UIImageView+Filter.h/m

回答1:

Easy... Make sure you import CoreImage framework

来源：https://stackoverflow.com/questions/20887624/symbols-not-found-for-architecture-armv7s-linker-command-failed-with-exit-cod