如果我这样称呼importUIKitimportMobileCoreServicesimportFoundationvarfileExtension:CFString="7z"asCFStringvarunmanagedFileUTI=UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension,fileExtension,nil)?.takeRetainedValue();print(unmanagedFileUTI)我明白了dyn.age8xs8u作为结果。我没有找到关于age8xs8u的任何信息。这是7z的正

importFoundationimportMobileCoreServicesfunccheckFileExtension(fileName:NSString){println(fileName)varfileExtension:CFStringRef=fileName.pathExtensionprintln(fileExtension)varfileUTI:CFStringRef=UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension,fileExtension,nil)println(fileUTI)

importFoundationimportMobileCoreServicesfunccheckFileExtension(fileName:NSString){println(fileName)varfileExtension:CFStringRef=fileName.pathExtensionprintln(fileExtension)varfileUTI:CFStringRef=UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension,fileExtension,nil)println(fileUTI)