通过扩展名获取文件类型描述

Question

How can I get the description of the file type like it does in Finder.app by using only file extension? In other words I want to get that field in NSString:

Answer 1

Here's a little something quick 'n' dirty that illustrates what you need:

NSOpenPanel *openPanel = [[NSOpenPanel alloc] init];

[openPanel runModal];

NSString *path = [[openPanel URL] path];
NSString *type = [[NSWorkspace sharedWorkspace] typeOfFile:path error:NULL];

NSLog(@"%@", [[NSWorkspace sharedWorkspace] localizedDescriptionForType:type]);

The open panel lets you choose a file. NSWorkspace provides for first determining the UTI of the file (given its path), and then using the UTI to get the localized string describing the file type.

EDIT:

If you positively have got to use only the file extension, then use these three lines instead of the last three above:

NSString *extension = [[[openPanel URL] path] pathExtension];
CFStringRef uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (__bridge CFStringRef) extension, NULL);

NSLog(@"%@", [[NSWorkspace sharedWorkspace] localizedDescriptionForType:(__bridge NSString *) uti]);

Answer 2

您应该通过将文件通用类型标识符提供给NSWorkspace的localizedDescriptionForType:来实现。