添加NSManagedObject子类，重复链接时出现重复的符号错误 [英] Duplicate symbol error when adding NSManagedObject subclass, duplicate link

问题描述

我试图在Xcode中自动创建NSManagedObject子类（2个相关实体）。它们是这样生成的：

I was trying to create NSManagedObject subclasses (2 related entities) automatically in Xcode. They are generated like this:

然而，在我做任何事情之前，当我尝试构建并运行它时，会发生链接错误，如图所示：

However, before I do anything further, when I tried to build and run it, a link error occur, as shown:


重复符号_OBJC_CLASS _ $ _照片输入：
/ Users / Kefeng / Library / Developer / Xcode / DerivedData / Photomania-aellrakjngugnzcgrleiytvrfvyt / Build / Intermediates / Photomania。 build / Debug-iphonesimulator / Photomania.build / Objects-normal / x86_64 / Photo + CoreDataClass.o
重复符号_OBJC_METACLASS _ $ _照片输入：
/ Users / Kefeng / Library / Developer / Xcode / DerivedData / Photomania -aellrakjngugnzcgrleiytvrfvyt / Build / Intermediates / Photomania.build / Debug-iphonesimulator / Photomania.build / Objects-normal / x86_64 / Photo + CoreDataClass.o
复制符号_OBJC_CLASS _ $ _摄影：
/ Users / Kefeng /图书馆/开发商/ Xcode中/ DerivedData / Photomania-aellrakjngugnzcgrleiytvrfvyt /编译/中间体/ Photomania.build / d ebug-iphonesimulator / Photomania.build / Objects-normal / x86_64 / Photography + CoreDataClass.o
复制符号_OBJC_METACLASS _ $ _摄影：
/ Users / Kefeng / Library / Developer / Xcode / DerivedData / Photomania-aellrakjngugnzcgrleiytvrfvyt /Build/Intermediates/Photomania.build/Debug-iphonesimulator/Photomania.build/Objects-normal/x86_64/Photography+CoreDataClass.o
ld：4个用于体系结构的重复符号x86_64
clang：error：linker命令退出代码1失败（使用-v查看调用）


我尝试了多次创建新项目并执行一样。我的初衷是将一些自定义方法添加到子类中。但是当我添加任何内容时，例如照片+ CoreData.h / m ，出现与上面相同的错误。

I tried several times by creating new projects and do the same thing. My original intention is to add some custom methods into those to subclasses. But when I add anything into e.g. Photo+CoreData.h/m, the same error as above showed up.

我找到了一些关于双重包含或将文件保存到错误的目录，但我没有这样做。有人对此有任何想法吗？

I found some answers about the "double include" or "save files to the wrong directory", but I didn't do that. Anybody have any idea about this?

推荐答案

如果您没有自动生成托管对象子类，那么不要忘记检查实体中的Codegen设置数据模型检查员：

If you do not generate managed object subclass automatically, then don't forget to check "Codegen" settings for an Entity in Data Model Inspector:

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