错误集-objc-class-ref in AppDelegate.o之解决方案

最近查看老项目Xcode版本从Xcode6.N进级到Xcode7.2后，顺序编译报错，出现问题：其实就是一个很常见的问题，很多项目在替换Xcode版本后都有如下报错

Undefined symbols for architecture x86_64:

  "_OBJC_CLASS_$_QQApiInterface", referenced from:

      objc-class-ref in AppDelegate.o

  "_OBJC_CLASS_$_ShareSDK", referenced from:

      objc-class-ref in AppDelegate.o

      objc-class-ref in RecipeDetailViewController.o

      objc-class-ref in showViewController.o

      objc-class-ref in video_show.o

  "_OBJC_CLASS_$_TencentOAuth", referenced from:

      objc-class-ref in AppDelegate.o

  "_OBJC_CLASS_$_WXApi", referenced from:

      objc-class-ref in AppDelegate.o

  "_OBJC_CLASS_$_WeiboApi", referenced from:

      objc-class-ref in AppDelegate.o

  "_OBJC_CLASS_$_YXApi", referenced from:

      objc-class-ref in AppDelegate.o

ld: symbol(s) not found for architecture x86_64

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

比如:Xcode升级到6.1.1 默认让所有App都通过64位编译器编译。原来在Xcode6.0的时候默认的Architectures只有（arm7,armv7s），到6.1.1默认就带上arm64的参数了。

解决方案：

• 1 .选中Targets—>Build Settings—>Architectures。

把build active architectures only 改为 NO。

• 2 . 把最下面的Valid Architectures中的arm64参数删掉就可以了

  或者：
  ‘双击

  Architectures

  选择other，删除

  $(ARCH_STANDARD)

  然后增加armv7和armv7s（写上：$(ARCHS_STANDARD_32_BIT)）。

  设置如图：

  

• 3.clean 再build。