iOS静态库编译错误 – 目录为空

Libtool /Users/******/Library/Developer/Xcode/DerivedData/MyLib-eyucoczochpovhcqduwoieknpyer/Build/Intermediates/MyLib.build/Debug-iphoneos/MyLib.build/Objects-normal/armv7/libMyLib.a normal armv7
cd /Users/******/Desktop/MyLib
export IPHONEOS_DEPLOYMENT_TARGET=7.1
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool -static -arch_only armv7 -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk -L/Users/******/Library/Developer/Xcode/DerivedData/MyLib-eyucoczochpovhcqduwoieknpyer/Build/Products/Debug-iphoneos -filelist /Users/******/Library/Developer/Xcode/DerivedData/MyLib-eyucoczochpovhcqduwoieknpyer/Build/Intermediates/MyLib.build/Debug-iphoneos/MyLib.build/Objects-normal/armv7/MyLib.LinkFileList -ObjC -framework Foundation -o /Users/shafraz/Library/Developer/Xcode/DerivedData/MyLib-eyucoczochpovhcqduwoieknpyer/Build/Intermediates/MyLib.build/Debug-iphoneos/MyLib.build/Objects-normal/armv7/libMyLib.a

我也得到了armv7s的类似错误,arm64也是如此

(null): /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/libtool: warning for library: /Users/******/Library/Developer/Xcode/DerivedData/MyLib-eyucoczochpovhcqduwoieknpyer/Build/Products/Debug-iphoneos/libMyLib.a for architecture: armv7 the table of contents is empty (no object file members in the library define global symbols)

我也得到了armv7s的类似错误,arm64也是如此

只有在MyLib.h文件中删除MyLib.m和类声明后才能显示此蠕虫.

我怎样才能解决这个问题？