title: What is the animation speed of the keyboard appearing in iOS8?
body: <p>The following is an animation for a textField and toolBar which move upward when the keyboard appears.</p>
  
  <pre><code>    baseConstraint.constant = 211
      self.view.setNeedsUpdateConstraints()
  
      UIView.animateWithDuration(0.30, animations: {
          self.view.layoutIfNeeded()
          })
  </code></pre>
  
  <p>It is close but not quite identical. How would you modify the above animation?</p>
  
  <p>Edit: </p>
  
  <p>Here is the final code using the answer below!</p>
  
  <pre><code>   func keyboardWillShow(aNotification: NSNotification)    {
  
          let duration = aNotification.userInfo.objectForKey(UIKeyboardAnimationDurationUserInfoKey) as Double
          let curve = aNotification.userInfo.objectForKey(UIKeyboardAnimationCurveUserInfoKey) as UInt
  
          self.view.setNeedsLayout()
          baseConstraint.constant = 211
          self.view.setNeedsUpdateConstraints()
  
          UIView.animateWithDuration(duration, delay: 0, options: UIViewAnimationOptions.fromMask(curve), animations: {
          self.view.layoutIfNeeded()
          }, completion: {
          (value: Bool) in println()
          })
  }
  </code></pre>