keyboard notifications

KeyboardNotifications.swift

func keyboardWillShow(notification: NSNotification) {
    print("Showing keyboard")
    guard let userInfo = notification.userInfo,
        rectValue = userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue,
        rawCurve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? UInt,
        duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? Double else {
            return
    }
    
    let keyboardFrame = rectValue.CGRectValue()
    let options = UIViewAnimationOptions(rawValue: rawCurve)
    UIView.animateWithDuration(duration, delay: 0, options: options, animations: {
        self.textViewBottomContraint.constant = keyboardFrame.height
        }, completion: { completed in
            
    })
}

func keyboardWillHide(notification: NSNotification) {
    guard let userInfo = notification.userInfo,
        rawCurve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? UInt,
        duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? Double else {
            return
    }
    
    let options = UIViewAnimationOptions(rawValue: rawCurve)
    UIView.animateWithDuration(duration, delay: 0, options: options, animations: {
        self.textViewBottomContraint.constant = 0
        }, completion: { completed in
            
    })
}