我知道这个问题之前已经被问过很多次了，但是直到现在都没有解决我的问题。我知道当您在项目中获得文件的多个副本时会发生此错误。我试图清理构建，删除编译源中的任何LoginController.m文件，然后构建。很好 - 没有错误。当我在 Complie 资源中添加我的 LoginController.m 文件时，编译器再次给出了同样的错误。
接下来我尝试的是从编译源中删除所有 .m 文件，成功清理和重建，并非常小心地添加每个 .m 文件。再次提出了同样的错误。我没有找到任何重复的文件，那为什么会发生这种情况？
请有人指导我。非常感谢。
编辑： 错误是：
Ld /Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Products/Debug-iphonesimulator/TryAgain.app/TryAgain normal i386
cd /Users/svp/Desktop/TryAgain
setenv MACOSX_DEPLOYMENT_TARGET 10.6
setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/clang -arch i386 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.0.sdk -L/Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Products/Debug-iphonesimulator -L/Users/svp/Desktop/TryAgain/TryAgain -L/Users/svp/Desktop/TryAgain/../CorePlot_1.0/Binaries/iOS -F/Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Products/Debug-iphonesimulator -filelist /Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Intermediates/TryAgain.build/Debug-iphonesimulator/TryAgain.build/Objects-normal/i386/TryAgain.LinkFileList -mmacosx-version-min=10.6 -Xlinker -objc_abi_version -Xlinker 2 -ObjC -all_load -fobjc-arc -D__IPHONE_OS_VERSION_MIN_REQUIRED=50000 -framework MediaPlayer -lz -framework AVFoundation -framework MobileCoreServices -framework SystemConfiguration -framework CFNetwork -framework QuartzCore -framework UIKit -framework Foundation -framework CoreGraphics -lCorePlot-CocoaTouch -o /Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Products/Debug-iphonesimulator/TryAgain.app/TryAgain
ld: duplicate symbol _OBJC_CLASS_$_LoginController in /Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Intermediates/TryAgain.build/Debug-iphonesimulator/TryAgain.build/Objects-normal/i386/LoginController.o and /Users/svp/Library/Developer/Xcode/DerivedData/TryAgain-dhbbyywxclvxfodbunqysmmfefcl/Build/Intermediates/TryAgain.build/Debug-iphonesimulator/TryAgain.build/Objects-normal/i386/Navigator.o for architecture i386
Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/clang failed with exit code 1