folder size wrong | 易学教程

问题

This code is correct but the folder size is wrong. If I change the directory the size is always wrong. For example the size of "%@/Caches/com.apple.Safari/Webpage Previews" is 23 MB, but I have 16.5 KB.

NSString *path = [NSString stringWithFormat:@"%@/Caches/com.apple.Safari/Webpage Previews", [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) objectAtIndex:0]];
    NSNumber *fileSize = [[[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil] objectForKey:NSFileSize];
    resultsize += [fileSize unsignedLongLongValue];

also I used this but the size is always wrong:

NSFileManager *fm = [[NSFileManager alloc] init];    
    NSURL *LibraryURL = [[fm URLsForDirectory:NSLibraryDirectory inDomains:NSUserDomainMask] lastObject];
    NSURL *previewsURL = [LibraryURL URLByAppendingPathComponent:@"Caches/com.apple.Safari/Webpage Previews"];

    resultSize += [[[fm attributesOfItemAtPath:[previewsURL path] error:nil] objectForKey:NSFileSize] unsignedIntegerValue];

Can you help me? Thanks.

回答1:

If you want to get the size of all the files in a folder, you'll need to iterate through the contents of the folder and get the sizes of the actual files:

unsigned long long totalSize = 0;
NSFileManager *fm = [[NSFileManager alloc] init];
NSURL *libraryURL = [[fm URLsForDirectory:NSLibraryDirectory inDomains:NSUserDomainMask] lastObject];
NSURL *previewsURL = [LibraryURL URLByAppendingPathComponent:@"Caches/com.apple.Safari/Webpage Previews"];

NSDirectoryEnumerator *enumerator = [fm enumeratorAtURL:previewsURL includingPropertiesForKeys:[NSArray arrayWithObject:NSURLFileSizeKey] options:0 errorHandler:nil /* or an actual error handler */];

for (NSURL *url in enumerator) {
    NSNumber *sizeNumber;
    if ([url getResourceValue:&sizeNumber forKey:NSURLFileSizeKey error:nil /* or an error */])
        totalSize += [sizeNumber unsignedLongLongValue]; 
}

(I haven't tested this.)

回答2:

Lion has some kind of Cache for these cumulative sizes. Try on a server volume (Mac OS X Lion Server AFP):

Open a Folder with lots of Subfolders
Menu View > as List
Menu View > Arrange By > Size
Finder shows all subfolders in the "---" group
Menu View > Show View Options
check the box "Calculate all File Sizes"
now Finders groups the subfolders appropriately
and even when you close that window, disconnect server and connect again, these sizes are there faster and also when not arranged by size

-> where is this information stored? which API to use?

来源：https://stackoverflow.com/questions/9064791/folder-size-wrong

标签

objective-c

macos

size

osx-lion