为什么我把src文件夹中的文件导入进入编译是错误的

[huangyunjin]

出现的UIDevice找不到 我加上#import <UIKit/UIKit.h>以后, 又显示 Undefined symbols for architecture x86_64: "OBJC_CLASS$_DOUMPMediaLibraryAssetLoader", referenced from: objc-class-ref in DOUAudioFileProvider.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)

这个是怎么回事

[liujinlongxa]

http://blog.csdn.net/h1101723183/article/details/40451493

[AixCoder]

楼上正解，3q