自 Swift 2.2 起无法访问 extern NSString [英] extern NSString not accessible since Swift 2.2

问题描述

自从使用 Swift 2.2 更新到 Xcode 7.3 后，我无法从外部 Objective-C 库访问变量.

Since the update to Xcode 7.3 with Swift 2.2 I am not able to access variables from an external Objective-C Library.

从今天开始我就可以访问这个变量了:

Since today I was able to access this variables:

extern NSString* const DEFAULT_URL;  

这是在来自预编译的 .a 框架的 Objective-C 头文件中定义的.

This is defined in an Objective-C Header file from a precompiled .a framework.

在我的 swift 代码中，我只需要调用 DEFAULT_URL.

In my swift code I only had to call DEFAULT_URL.

从 Swift 2.2 开始，我收到以下错误:

Since Swift 2.2 I get the following errror:

Use of unresolved identifier 'DEFAULT_URL'  

我可以访问这个框架的类和方法，但是我不能访问extern NSStrings.

I am able to access the classes and methods of this framework, but I can't access extern NSStrings.

任何想法如何解决这个问题?

Any ideas how to fix this?

推荐答案

@patrickS 我有一个愚蠢的原因，我的 extern const 是在我的 .h 文件中的 @interface 中定义的.这似乎使它成为这个版本的 XCode/Clang 的 Swift 代码私有的.它适用于所有 extern consts，而不仅仅是 NSString *.

@patrickS I had this for a silly reason, my extern const was defined inside an @interface in my .h file. This seems to have made it private to Swift code with this version of XCode / Clang. It applies to all extern consts not just NSString *.

例如

//In Foo.h
extern const int kBlah

@interface Foo
...
@end

代替

//In Foo.h
@interface Foo
extern const int kBlah
...
@end

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