相关疑难解决方法(0)

我一直试图转换这个代码,我从这个例子(在Objective-c中)没有运气.

    String *path; // contains the file path

    // Get the UTI from the file's extension:

    CFStringRef pathExtension = (__bridge_retained CFStringRef)[path pathExtension];
    CFStringRef type = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension, NULL);
    CFRelease(pathExtension);

    // The UTI can be converted to a mime type:

    NSString *mimeType = (__bridge_transfer NSString *)UTTypeCopyPreferredTagWithClass(type, kUTTagClassMIMEType);
    if (type != NULL)
        CFRelease(type);

我的代码是这样的

    import MobileCoreServices
    let path: String?
    let pathExt = path.pathExtension as CFStringRef
    let type = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension, NULL);
    let mimeType = UTTypeCopyPreferredTagWithClass(type, kUTTagClassMIMEType)
    if type != Null …