为iPhone编译时出现Obj类引用错误

这是我尝试运行文件时遇到的错误。。。我已经将这些类从另一个项目导入到这个项目中，这个项目是非基于arc的，并转换为arc。在成功删除对autorelease的所有引用并从中保留后，我出现此错误。

是否尝试过产品->清理？ 还是重新启动XCode？

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您是否确保在目标->构建阶段->编译源代码中包含了所有内容？Xcode可以为您实现这一点，但有时它会遗漏一些内容。

在其他一些类中声明了重复的变量。参考和清理目标，然后运行项目…我认为我没有任何重复的变量。。。。他们只是没有被包括在项目中。只是为了让未来的人们知道，我的建议中哪一个有效？第二个。。将文件添加到编译源。我以前没看过。。不知怎么错过了。

Ld /Users/rajeshmedampudi/Library/Developer/Xcode/DerivedData/sampleResource-flngddqnaawregcrrshzpianssjc/Build/Products/Debug-iphonesimulator/sampleResource.app/sampleResource normal i386
    cd /Users/rajeshmedampudi/Dropbox/Work/iphone/sampleResource
    setenv MACOSX_DEPLOYMENT_TARGET 10.6
    setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.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/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk -L/Users/rajeshmedampudi/Library/Developer/Xcode/DerivedData/sampleResource-flngddqnaawregcrrshzpianssjc/Build/Products/Debug-iphonesimulator -F/Users/rajeshmedampudi/Library/Developer/Xcode/DerivedData/sampleResource-flngddqnaawregcrrshzpianssjc/Build/Products/Debug-iphonesimulator -filelist /Users/rajeshmedampudi/Library/Developer/Xcode/DerivedData/sampleResource-flngddqnaawregcrrshzpianssjc/Build/Intermediates/sampleResource.build/Debug-iphonesimulator/sampleResource.build/Objects-normal/i386/sampleResource.LinkFileList -mmacosx-version-min=10.6 -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -Xlinker -no_implicit_dylibs -D__IPHONE_OS_VERSION_MIN_REQUIRED=50100 -framework UIKit -framework Foundation -framework CoreGraphics -o /Users/rajeshmedampudi/Library/Developer/Xcode/DerivedData/sampleResource-flngddqnaawregcrrshzpianssjc/Build/Products/Debug-iphonesimulator/sampleResource.app/sampleResource

Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_User", referenced from:
      objc-class-ref in AppDelegate.o
  "_OBJC_CLASS_$_AuthenticationViewController", referenced from:
      objc-class-ref in AppDelegate.o
  "_OBJC_CLASS_$_AppHelpers", referenced from:
      objc-class-ref in AppDelegate.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)