NSFileManager not saving Data - ios

Question

I am trying to save data into a directory created by NSFileManager but when I try and retrieve the data and NSLog it I get null. Also, when you create a directory does that mean you create a folder at a specified url path? Heres the code I am using
NSError *error = nil;
NSFileManager *manager = [[NSFileManager alloc] init];
NSArray *urlsArray = [manager URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask];
NSLog(#"%#", urlsArray);
// This will create a new url and append a photo title to the end
NSURL *url = [[urlsArray lastObject] URLByAppendingPathComponent:[NSString stringWithFormat:#"%#", [self.recentPhoto objectForKey:FLICKR_PHOTO_TITLE]]];
NSLog(#"%#", url);
NSString *urlString = [NSString stringWithFormat:#"%#", [url absoluteString]];
NSLog(#"%#", urlString);
//create the directory
if(![manager fileExistsAtPath:urlString isDirectory:YES]){
BOOL success = [manager createDirectoryAtURL:url withIntermediateDirectories:YES attributes:nil error:&error];
if (!success) {
NSLog(#"Error creating data path: %#", [error localizedDescription]);
}
}
//get url for a photo image and then store it.
NSURL *imageURL = [FlickrFetcher urlForPhoto:self.recentPhoto format:FlickrPhotoFormatLarge];
NSData *imageData = [[NSData alloc] initWithContentsOfURL:imageURL];
[imageData writeToURL:url atomically:YES];
//get data to check if its stored
NSData *checkImageData = [[NSData alloc] initWithContentsOfURL:url];
//This returns null
NSLog(#"%#", checkImageData);
//this returns 0
NSLog(#"%d", [manager isReadableFileAtPath:urlString]);

Answer 1

There are several issues with your code.
This:
NSURL *url = [[urlsArray lastObject] URLByAppendingPathComponent:[NSString stringWithFormat:#"%#", [self.recentPhoto objectForKey:FLICKR_PHOTO_TITLE]]];
should be:
NSURL *url = [[urlsArray lastObject] URLByAppendingPathComponent:[self.recentPhoto objectForKey:FLICKR_PHOTO_TITLE]];
This:
NSString *urlString = [NSString stringWithFormat:#"%#", [url absoluteString]];
should be:
NSString *urlString = [url path];
This:
BOOL success = [manager createDirectoryAtURL:url withIntermediateDirectories:YES attributes:nil error:&error];
should be:
BOOL success = [manager createDirectoryAtURL:[url URLByDeletingLastPathComponent] withIntermediateDirectories:YES attributes:nil error:&error];
This:
[imageData writeToURL:url atomically:YES];
should be:
NSError *error = nil;
BOOL res = [imageData writeToURL:url options:NSDataWritingAtomic error:&error];
if (!res) {
NSLog(#"Unable to write to %#: %#", url, error);
}
The primary issue was the use of absoluteString instead of path to convert the URL to a file path. Secondary was passing the filename instead of the path when creating the directory. The needless use of stringWithFormat: didn't cause any issues but please break that habit now. Only use stringWithFormat: when you actually need to format a string. It is NOT needed to assign a string to a string variable.

Answer 2

You didn't specify a file name for your image inside the directory, this can be solved by adding this line right after the directory is created :
// Right after the directory is created (I suppose the format is png) :
url = [url URLByAppendingPathComponent:#"image.png"];
// Now you can continue with the rest of your code :
//get url for a photo image and then store it.
NSURL *imageURL = [FlickrFetcher urlForPhoto:self.recentPhoto format:FlickrPhotoFormatLarge];
NSData *imageData = [[NSData alloc] initWithContentsOfURL:imageURL];
[imageData writeToURL:url atomically:YES];
//get data to check if its stored
NSData *checkImageData = [[NSData alloc] initWithContentsOfURL:url];
//This returns null
NSLog(#"%#", checkImageData);
//this returns 0
NSLog(#"%d", [manager isReadableFileAtPath:urlString]);

Answer 3

I have never created an instance of a file manager. I have always simply used the default.
See if this helps:
NSFileManager *manager = [NSFileManager defaultManager];