問題： 在和Unity交互的過程中，從Unity開發工具打包出來的項目文件，在添加AFNetworking庫，運行時報出以下錯誤： Undefined symbols for architecture armv7: "_kUTTagClassMIMEType", referenced from: - ...
問題： 在和Unity交互的過程中，從Unity開發工具打包出來的項目文件，在添加AFNetworking庫，運行時報出以下錯誤：
Undefined symbols for architecture armv7:
"_kUTTagClassMIMEType", referenced from:
-[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o
"_kUTTagClassFilenameExtension", referenced from:
-[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o
"_UTTypeCreatePreferredIdentifierForTag", referenced from:
-[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o
"_UTTypeCopyPreferredTagWithClass", referenced from:
-[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
原因是未添加 MobileCoreServices.framework（此框架定義統一類型標識符 (UTIs)使用的底層類型）
解決：Build Phase ->Link Binary With Libraries()下添加 MobileCoreServices.framework。添加成功後運行程式成功。
