Xcode 4.3.3-错误未定义符号

Question

hy all, I am building an application to create a simple tableview, with a search bar on top to search between the elements of the table. I have followed a tutorial and no coding errors were found, but when building, it always fails showing the following message:

Ld /Users/gouyoun/Library/Developer/Xcode/DerivedData/ERCDictionnary-atjolczeormaykcscwvnhlxdcnvk/Build/Products/Debug-iphonesimulator/ERCDictionnary.app/ERCDictionnary normal i386
cd /Users/gouyoun/Desktop/ERCDictionnary/ERCDictionnary
setenv MACOSX_DEPLOYMENT_TARGET 10.6
setenv PATH "/Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Volumes/Xcode/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Volumes/Xcode/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk -L/Users/gouyoun/Library/Developer/Xcode/DerivedData/ERCDictionnary-atjolczeormaykcscwvnhlxdcnvk/Build/Products/Debug-iphonesimulator -F/Users/gouyoun/Library/Developer/Xcode/DerivedData/ERCDictionnary-atjolczeormaykcscwvnhlxdcnvk/Build/Products/Debug-iphonesimulator -filelist /Users/gouyoun/Library/Developer/Xcode/DerivedData/ERCDictionnary-atjolczeormaykcscwvnhlxdcnvk/Build/Intermediates/ERCDictionnary.build/Debug-iphonesimulator/ERCDictionnary.build/Objects-normal/i386/ERCDictionnary.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/gouyoun/Library/Developer/Xcode/DerivedData/ERCDictionnary-atjolczeormaykcscwvnhlxdcnvk/Build/Products/Debug-iphonesimulator/ERCDictionnary.app/ERCDictionnary

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

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

I'm a newb in OBjective C, any ideas?

Answer 1

您的tableView类引用了一个不在项目中的名为OverlayViewController的类。

Answer 2

完成后，只需删除文件并稍后重新添加它们，就可以像魅力一样工作

Answer 3

I've had the exact same error. It occured because I had 2 xCode Projects open, an Dragged & Dropped a class from one project to the other one. I checked "Copy to project" and the files where in the new projects folder. But it crashed every time.

I deleted the classes and IMPORTED them into the project and then it worked... So be careful when using Drag'n'Drop!