How to scroll UITableView on height change?

Question

iOS

func keyboardWillShow(sender: NSNotification) {
        let duration = sender.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
        let curve = sender.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt

        let info: NSDictionary = sender.userInfo!
        let value: NSValue = info.valueForKey("UIKeyboardFrameEndUserInfoKey") as! NSValue
        let keyboardSize: CGSize = value.CGRectValue().size
        
        UIView.animateWithDuration(duration, delay: 0, options: UIViewAnimationOptions(rawValue: curve), animations: {
            
            self.contentBottomConstrains.constant = keyboardSize.height
            self.tableView.scrollToRowAtIndexPath(NSIndexPath(forRow: self.messages.count-1, inSection: 0), atScrollPosition: UITableViewScrollPosition.Top, animated: true)
            self.view.layoutIfNeeded()

            }, completion: nil)
        
    }

This code changes the padding from the bottom of the superview, raising the input field to the height of the keyboard, but does not want to scroll the table down. Please help me find and fix the error.

Answer 1

Transfer the code
in completionBlock.
Now at the time of the call, the table still has the old dimensions. At the same time, scrollToRow.... will create the animation on its own.