Get directory contents in date modified order

Question

Is there an method to get the contents of a folder in a particular order? I'd like an array of file attribute dictionaries (or just file names) ordered by date modified.

Right now, I'm doing it this way:

• get an array with the file names
• get the attributes of each file
• store the file's path and modified date in a dictionary with the date as a key

Next I have to output the dictionary in date order, but I wondered if there's an easier way? If not, is there a code snippet somewhere which will do this for me?

Thanks.

Answer 1

nall's code above pointed me in the right direction, but I think there are some mistakes in the code as posted above. For instance:

1. Why is filesAndProperties allocated using NMutableDictonary rather than an NSMutableArray?



2.  NSDictionary* properties = [[NSFileManager defaultManager]                                         attributesOfItemAtPath:NSFileModificationDate                                         error:&error];  

   The code above is passing the wrong parameter for attributesOfItemAtPath - it should be attributesOfItemAtPath:path


3. Your are sorting the files array, but you should be sorting filesAndProperties.

I have implemented the same, with corrections, and using blocks and posted below:

     NSArray *searchPaths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);     NSString* documentsPath = [searchPaths objectAtIndex: 0];       NSError* error = nil;     NSArray* filesArray = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsPath error:&error];     if(error != nil) {         NSLog(@"Error in reading files: %@", [error localizedDescription]);         return;     }      // sort by creation date     NSMutableArray* filesAndProperties = [NSMutableArray arrayWithCapacity:[filesArray count]];     for(NSString* file in filesArray) {         NSString* filePath = [iMgr.documentsPath stringByAppendingPathComponent:file];         NSDictionary* properties = [[NSFileManager defaultManager]                                     attributesOfItemAtPath:filePath                                     error:&error];         NSDate* modDate = [properties objectForKey:NSFileModificationDate];          if(error == nil)         {             [filesAndProperties addObject:[NSDictionary dictionaryWithObjectsAndKeys:                                            file, @"path",                                            modDate, @"lastModDate",                                            nil]];                          }     }          // sort using a block         // order inverted as we want latest date first     NSArray* sortedFiles = [filesAndProperties sortedArrayUsingComparator:                             ^(id path1, id path2)                             {                                                                // compare                                  NSComparisonResult comp = [[path1 objectForKey:@"lastModDate"] compare:                                                            [path2 objectForKey:@"lastModDate"]];                                 // invert ordering                                 if (comp == NSOrderedDescending) {                                     comp = NSOrderedAscending;                                 }                                 else if(comp == NSOrderedAscending){                                     comp = NSOrderedDescending;                                 }                                 return comp;                                                             }];  

Answer 2

How about this:

// Application documents directory NSURL *documentsURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];  NSArray *directoryContent = [[NSFileManager defaultManager] contentsOfDirectoryAtURL:documentsURL                                                           includingPropertiesForKeys:@[NSURLContentModificationDateKey]                                                                              options:NSDirectoryEnumerationSkipsHiddenFiles                                                                                error:nil];  NSArray *sortedContent = [directoryContent sortedArrayUsingComparator:                         ^(NSURL *file1, NSURL *file2)                         {                             // compare                             NSDate *file1Date;                             [file1 getResourceValue:&file1Date forKey:NSURLContentModificationDateKey error:nil];                              NSDate *file2Date;                             [file2 getResourceValue:&file2Date forKey:NSURLContentModificationDateKey error:nil];                              // Ascending:                             return [file1Date compare: file2Date];                             // Descending:                             //return [file2Date compare: file1Date];                         }];