为什么UIDocumentMenuViewController不接受kUTTypeText？

Question

我在this教程和Apple docs中看到，这一堆代码应该可行。

let d = UIDocumentMenuViewController(documentTypes: [kUTTypeText as NSString], inMode: .Import)
o.delegate = self
self.presentViewController(d, animated: true, completion: nil)

但是我收到编译时错误

Answer 1

kUTTypeText在MobileCoreServices框架中定义，因此您应该添加

import MobileCoreServices

此外，正如Bartłomiej正确注意到的那样，必须转换类型标识符 从Swift 2 / Xcode 7中的CFString到String：

UIDocumentMenuViewController(documentTypes: [kUTTypeText as String], inMode: .Import)