Resizable inputAccessoryView on UITableView in iOS 8

gistfile1.swift

import UIKit

class InputAccessoryTableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.tableView.becomeFirstResponder()
    }
    
    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 20
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("reuseIdentifier", forIndexPath: indexPath)

        cell.textLabel?.text = "\(indexPath.row + 1)"

        return cell
    }
}


class InputAccessoryTableView: UITableView, UITextViewDelegate {
  
    var accessoryView: UIView!
    
    override var inputAccessoryView: UIView? {
        get {
            if self.accessoryView == nil {
                self.accessoryView = UIView(frame: CGRectMake(0, 0, 320, 46))
                self.accessoryView.backgroundColor = UIColor.groupTableViewBackgroundColor()

                let textView = UITextView(frame: CGRectMake(8, 8, 304, 30))
                textView.translatesAutoresizingMaskIntoConstraints = false
                textView.delegate = self
                self.accessoryView.addSubview(textView)
                
                let viewBindingsDict = ["textView" : textView]
                self.accessoryView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-8-[textView]-8-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: viewBindingsDict))
                self.accessoryView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-8-[textView]-8-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: viewBindingsDict))
            }
            
            return self.accessoryView
        }
    }
    
    override func canBecomeFirstResponder() -> Bool {
        return true
    }
    
    func textViewDidChange(textView: UITextView) {
        print(textView.contentSize)
        
        for constraint in self.accessoryView.constraints where constraint.firstAttribute == .Height {
            print(constraint)
            constraint.constant = textView.contentSize.height + 16
        }
        
        //self.reloadInputViews()
    }
}