Question

So I know iOS apps run in a sandbox and all, but I thought I remembered Apple mentioning a way for apps to write to and read from a common file share, so that you can then deal with these files on your computer when you plug you iPhone in (mount the drive). I think this was in the context on the iPad, but I’m not sure.

Anybody know anything more of this? It’s kind of a tough thing to search for.

Answer 1

Each app has a Documents directory where it can write files. To get the apps Documents directory you can use:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

To write say “Hello, World!” to a file called hello.txt in the documents directory you could do something like:

NSString *hello = @"Hello, World!";
NSString *myFile = [documentsDirectory stringByAppendingPathComponent:@"hello.txt"];
[hello writeToFile: myFile atomically:YES encoding:NSUTF8StringEncoding error:NULL];

If you set UIFileSharingEnabled in your app’s Info.plist to YES the the files will be visible in iTunes when the device is connected and can be accessed by the user from there.