iOS 7 Programming Cookbook

14.4. Enumerating Files and Folders

Problem

You either want to enumerate folders within a folder or you want to enumerate the list of files inside a folder. The act of enumerating means that you simply want to find all the folders and/or files within another folder.

Solution

Use the contentsOfDirectoryAtPath:error: instance method of the NSFileManager class as shown here. In this example, we are enumerating all the files, folders, and symlinks under our app’s bundle folder:

- (BOOL)            application:(UIApplication *)application
  didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
    
    NSFileManager *fileManager = [[NSFileManager alloc] init];
    NSString *bundleDir = [[NSBundle mainBundle] bundlePath];
    
    NSError *error = nil;
    NSArray *bundleContents = [fileManager
                               contentsOfDirectoryAtPath:bundleDir
                               error:&error];
    
    if ([bundleContents count] > 0 &&
        error == nil){
        NSLog(@"Contents of the app bundle = %@", bundleContents);
    }
    else if ([bundleContents count] == 0 &&
             error == nil){
        NSLog(@"Call the police! The app bundle is empty.");
    }
    else {
        NSLog(@"An error happened = %@", error);
    }
    
    self.window = [[UIWindow alloc]
                   initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    return YES;
}

Discussion

In some of your iOS apps, you may need to enumerate the contents of a folder. Let me give you an example, in case this need is a bit vague right now. Imagine that the user ...