有没有办法在Cocoa中获取文件夹的创建日期？

Question

I tried with NSFileManager's attributesOfItemAtPath. It works well with files, but not with folders. Although in Apple's documentation , they claimed it should work either on file or folder. But all I get is a nil value if I call this on folders.

Code I use:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

NSDictionary *folderAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:somePath error:nil];

NSLog(@"Creation date: %@", [dateFormatter stringFromDate:[folderAttributes objectForKey:NSFileCreationDate]]);

The output is always null to me. My "somePath" is an NSString, with a format like this:

file://localhost/Users/username/...

Thoughts? Thanks!

Answer 1

If it's a path, don't use a URL. Use a path:

/Users/username/dir

Also, get used to the error parameter, it's really helpful.

NSError *error = nil;
NSDictionary *attr = [fm attributesOfItemAtPath:path error:&error];
if (error)
    NSLog(@"%@", error) /* at least */

It will help you. And if for some reason you don't want it, notice the parameter is a pointer to object, so you may want to use NULL instead of nil .

Answer 2

somePath应格式化为直接POSIX路径 - 将其设置为/ Users / username / ... - 应该可以工作。