How to detect total available/free disk space on the iPhone/iPad device?

Question

I\'m looking for a better way to detect available/free disk space on the iPhone/iPad device programmatically.
Currently I\'m using the NSFileManager to detect the disk s

Answer 1

If your looking to get the the remaining free space using Swift it is slightly different. You need to use attributesOfFileSystemForPath() instead of attributesOfItemAtPath():

func deviceRemainingFreeSpaceInBytes() -> Int64? {
    let documentDirectoryPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    var attributes: [String: AnyObject]
    do {
        attributes = try NSFileManager.defaultManager().attributesOfFileSystemForPath(documentDirectoryPath.last! as String)
        let freeSize = attributes[NSFileSystemFreeSize] as? NSNumber
        if (freeSize != nil) {
            return freeSize?.longLongValue
        } else {
            return nil
        }
    } catch {
        return nil
    }
}

Edit: Updated for Swift 1.0
Edit 2: Updated for safety, using Martin R's answer.
Edit 3: Updated for Swift 2.0 (by dgellow)