http://stackoverflow.com/questions/15057273/duplicate-symbols-for-architecture-i386-and-couldnt-find-same-name-of-class-and
解决：
Go to Project Target-> Build Phases->Look for multiple occurrences of same file under "Compile Sources".
You can search for file name there as well.
Remove multiple occurrences from there.
中一个即可是因为文件重复引用引起的. 解决办法很简单: 自己查看你的工程文件,看看有哪个文件导入了两次,删掉其中一个即可