将NSManagedObject子类化为swift 3和Xcode 8 beta [英] Subclassing NSManagedObject with swift 3 and Xcode 8 beta

问题描述

我开始尝试使用Core data with swift 3和Xcode 8 beta。当我尝试从核心数据模型生成NSManagedObject子类，并在编辑器菜单中创建NSManagedObject子类...选项时，Xcode 8 beta生成三个文件，其中之一是 _COREDATA_DATAMODELNAME _ + CoreDataModel.swift，具有以下内容：

I've began to try use Core data with swift 3 and Xcode 8 beta. When I try to generate NSManagedObject subclasses from core data model and Create NSManagedObject subclass… option in Editor menu, Xcode 8 beta generates three files one of them is _COREDATA_DATAMODELNAME_+CoreDataModel.swift with the following content:

import Foundation
import CoreData

___COREDATA_DATAMODEL_MANAGEDOBJECTCLASSES_IMPLEMENTATIONS___

此外，此文件的内容显示两个警告：

In addition, the content of this file shows two warnings:

Expressions are not allowed at the top level.
Use of unresolved identifier '___COREDATA_DATAMODEL_MANAGEDOBJECTCLASSES_IMPLEMENTATIONS___'

有任何人面临同样的问题吗？

Has anyones faced the same issue? Which is the meaning of this new file?

感谢

推荐答案

它可能是一个（beta）与新的自动子类生成冲突，可以在数据模型文件的实体检查器中控制。

It's probably a (beta) clash with the new automatic subclass generation, which can be controlled in the entity inspector of the data model file.

从文档（核心数据中的新功能）

Xcode现在支持自动生成 NSManagedObject 建模工具中的子类
。在实体检查器中：

Xcode automatic subclass generation

Xcode now supports automatic generation of NSManagedObject subclasses in the modeling tool. In the entity inspector:

• 手动/无在这种情况下，你
  应该实现你自己的子类或使用 NSManagedObject 。


• 类别/ >在名为
  ClassName + CoreDataGeneratedProperties 的文件中生成类扩展。你需要声明/ implement
  主类（如果在Obj-C中，通过标题扩展可以导入
  名为ClassName.h）。 -


• 类定义生成名为
  的子类文件，例如 ClassName + CoreDataClass 为
  类别/扩展生成的文件。

• Manual/None is the default, and previous behavior; in this case you should implement your own subclass or use NSManagedObject.
• Category/Extension generates a class extension in a file named like ClassName+CoreDataGeneratedProperties. You need to declare/implement the main class (if in Obj-C, via a header the extension can import named ClassName.h). -
• Class Definition generates subclass files named like ClassName+CoreDataClass as well as the files generated for Category/Extension.

保存模型后，生成的文件放在DerivedData中，
在第一次构建时重建。他们也是
索引的Xcode，所以命令点击引用和快速打开
通过文件名。

The generated files are placed in DerivedData and rebuilt on the first build after the model is saved. They are also indexed by Xcode, so command-clicking on references and fast-opening by filename works.

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