Xcode 解决_OBJC_CLASS_$_某文件名", referenced from:

Undefined symbols for architecture arm64:
  "_OBJC_CLASS_$_DDTTYLogger", referenced from:
      objc-class-ref in AppDelegate.o
  "_OBJC_CLASS_$_DDFileLogger", referenced from:
      objc-class-ref in AppDelegate.o
  "_OBJC_CLASS_$_DDLog", referenced from:
      objc-class-ref in AppDelegate.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

1、Compile Sources就是.h和.m文件的集合