Finding Directories in iOS

I created a Utilities singleton to keep things I refer to often. These are the methods I use for referring to directories.

#pragma mark - Application's Documents directory
// Directory locations
+ (NSString *)applicationCachesDirectory {
    return [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
}

+ (NSString *)applicationDocumentsDirectory {
    return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}

+ (NSString *)applicationLibraryDirectory {
    
    return [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];
}

Here’s one for retrieving the contents of a file stored in the Caches Directory. Notice how it uses [self applicationCachesDirectory] to get the location of the directory.

// Cached files for results
+ (NSString *)cachedFilePath:(NSString *)fileName {
    NSString *pathComponent = [NSString stringWithFormat:@"%@.txt",fileName];
    NSString *filePath = [[self applicationCachesDirectory] stringByAppendingPathComponent:pathComponent];
    return filePath;
}

If I want to store the results in the Documents directory, I’ll use this to construct the path.

        NSString *resultsFilePath = [ [Utilities applicationDocumentsDirectory] stringByAppendingPathComponent:[self formattedHTMLFileName:@"Results"] ];

Here’s a slightly more complicated example where I retrieve the contents of a cached file. Note that it makes use of cachedFilePath:fileName as described above.

+ (NSString *)cachedFileContents:(NSString *)fileName {
    NSStringEncoding encoding; NSError* error = nil;
    NSString *text = [NSString stringWithContentsOfFile:[self cachedFilePath:fileName] usedEncoding:&encoding error:&error];
    return text;
}

Here’s another example. This time I’m loading a string with the contents of the FullResults file.

 NSStringEncoding encoding;
    NSError* error = nil;
    NSString *resultsText = [NSString stringWithContentsOfFile:[Utilities cachedFilePath:@"FullResults"] usedEncoding:&encoding error:&error];