Keyboard Change Frame Notification

gistfile1.swift

        NSNotificationCenter.defaultCenter().addObserverForName(UIKeyboardWillChangeFrameNotification, object: nil, queue: nil) { (notification) -> Void in
            guard let info: [NSObject: AnyObject] = notification.userInfo,
            let keyboardFrameValue = info[UIKeyboardFrameEndUserInfoKey] as? NSValue,
            let duration = info[UIKeyboardAnimationDurationUserInfoKey] as? Int else {
                return
            }
        
             let diff = CGRectGetHeight(keyboardFrameValue.CGRectValue()) 
             UIView.animateWithDuration(Double(duration), animations: {      () -> Void in
                self.view.frame = CGRect(x: self.view.frame.minX, y: keyboardFrameValue.CGSizeValue().height, width: self.view.frame.width, height: self.view.frame.height)
                self.view.layoutIfNeeded()
        })
    }