Undefined symbols for architecture i386:
"_OBJC_CLASS_$_SearchResultController", 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)
原因是,找不到SearchResultController这个文件，
解决办法，把这个文件添加到项目中（记住要选择copy）