1 duplicate symbol for architecture x86_64

1. 拷贝文件时，两个文件有重复。

错误信息：

duplicate symbol _kRefreshBoundary in:

    /Users/jointsky/Library/Developer/Xcode/DerivedData/SearchPigeonWorld-eowxiueoysjuhsfcfhwittfroooe/Build/Intermediates/SearchPigeonWorld.build/Debug-iphonesimulator/SearchPigeonWorld.build/Objects-normal/x86_64/ViewTwoController.o

    /Users/jointsky/Library/Developer/Xcode/DerivedData/SearchPigeonWorld-eowxiueoysjuhsfcfhwittfroooe/Build/Intermediates/SearchPigeonWorld.build/Debug-iphonesimulator/SearchPigeonWorld.build/Objects-normal/x86_64/ViewOneController.o

ld: 1 duplicate symbol for architecture x86_64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

解决方法：ViewOneController.m 中有  constCGFloat kRefreshBoundary =170.0f;

ViewTwoController.m 中也有  const CGFloat kRefreshBoundary = 170.0f;

删除其中一条即可。