学步园

'Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_CustomTabBar", referenced from objc-class-ref in
ViewController.o
ld: symbol(s) not found for architecture i386

clang: error: linker command failed with exit code 1 (use -v to see invocation)'

问题原因：我xcode版本为4.3.1,在引入CustomTabBar时候，4.3.1默认没有勾选targert，所以导致上述错误。