Ios 无法生成Objective-C模块'；CoreFoundation'；

在通过CocoaPods更新Firebase后，我遇到了这个问题

非常感谢您的帮助

任何超过4.0.2的Firebase版本都会在Xcode（版本10.1）中导致相同的错误

错误：

Swift编译器错误

• 找不到“字符串”文件

• 无法生成Objective-C模块“CoreFoundation”

已尝试：

• 清洁工程

• 手动添加SDK

• 删除级别db并手动添加

问题在哪里？使用Swift文件/标题？用leveldb？还是火基

相关（GitHub上的类似问题，但建议的解决方案对我不起作用）：

Xcode消息：

> <module-includes>:1:9: note: in file included from
> <module-includes>:1:
> #import "Headers/CoreFoundation.h"
>         ^ /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CoreFoundation.h:43:10:
> note: in file included from
> /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CoreFoundation.h:43:
> #include <CoreFoundation/CFBase.h>
>          ^ /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CFBase.h:72:10:
> note: in file included from
> /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CFBase.h:72:
> #include <Block.h>
>          ^ /Users/Besfort/Desktop/Coding/Xcode - projects/0.1/Pods/leveldb-library/table/Block.h:10:10: note: in file
> included from /Users/Besfort/Desktop/Coding/Xcode -
> projects/0.1/Pods/leveldb-library/table/Block.h:10:
> #include "leveldb/iterator.h"
>          ^ /Users/Besfort/Desktop/Coding/Xcode - projects/0.1/Pods/leveldb-library/include/leveldb/iterator.h:18:10:
> note: in file included from /Users/Besfort/Desktop/Coding/Xcode -
> projects/0.1/Pods/leveldb-library/include/leveldb/iterator.h:18:
> #include "leveldb/slice.h"
>          ^ /Users/Besfort/Desktop/Coding/Xcode - projects/0.1/Pods/leveldb-library/include/leveldb/slice.h:21:10:
> error: 'string' file not found
> #include <string>
>          ^ <unknown>:0: error: could not build Objective-C module 'CoreFoundation'

:1:9:注意：在包含的文件中
> :1:
>#导入“Headers/CoreFoundation.h”
>^/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CoreFoundation.h:43:10:
>注：在文件中包括从
>/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CoreFoundation.h:43：
>#包括
>^/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CFBase.h:72:10:
>注：在文件中包括从
>/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk/System/Library/Frameworks/CoreFoundation.framework/Headers/CFBase.h:72：
>#包括
>^/Users/Besfort/Desktop/Coding/Xcode-projects/0.1/Pods/leveldb library/table/Block.h:10:10:注意：在文件中
>包含在/Users/Besfort/Desktop/Coding/Xcode中-
>projects/0.1/Pods/leveldb library/table/Block.h:10：
>#包括“leveldb/iterator.h”
>^/Users/Besfort/Desktop/Coding/Xcode-projects/0.1/Pods/leveldb-library/include/leveldb/iterator.h:18:10：
>注意：在/Users/Besfort/Desktop/Coding/Xcode中包含的文件中-
>projects/0.1/Pods/leveldb library/include/leveldb/iterator.h:18：
>#包括“leveldb/slice.h”
>^/Users/Besfort/Desktop/Coding/Xcode-projects/0.1/Pods/leveldb-library/include/leveldb/slice.h:21:10：
>错误：找不到“字符串”文件
>#包括
>^：0:错误：无法生成Objective-C模块“CoreFoundation”