ld：在我的pod类中找不到架构x86_64的符号

Question

我更新了我的播客。更新后，由于以下错误，我无法启动我的应用程序：

Undefined symbols for architecture x86_64:
      "_OBJC_CLASS_$_DownPicker", referenced from:
          objc-class-ref in ChooseBookViewController.o
      "_OBJC_CLASS_$_FBSDKAppEvents", referenced from:
          objc-class-ref in AnalyticsProvider.o
      "_OBJC_CLASS_$_FBSDKApplicationDelegate", referenced from:
          objc-class-ref in AppDelegate.o
      "_OBJC_CLASS_$_Mixpanel", referenced from:
          objc-class-ref in AnalyticsProvider.o
      "_OBJC_CLASS_$_PHFComposeBarView", referenced from:
          objc-class-ref in ForumBaseVC.o
      "_OBJC_CLASS_$_RKDynamicMapping", referenced from:
          objc-class-ref in WikiArticle.o
      "_OBJC_CLASS_$_RKObjectManager", referenced from:
          objc-class-ref in MLDataProvider.o
      "_OBJC_CLASS_$_RKObjectMapping", referenced from:
          objc-class-ref in WikiError.o
          objc-class-ref in WikiArticle.o
          objc-class-ref in WikiLogin.o
          objc-class-ref in WikiQuery.o
          objc-class-ref in Model.o
          objc-class-ref in WikiThumbnail.o
          objc-class-ref in MLError.o

我该如何解决这个问题？

此致