DDHTweaks_post_2

override func viewWillAppear(_ animated: Bool) {
  super.viewWillAppear(animated)
  
  labelTopConstraint.constant = -40
  labelUsernameConstraint.constant = -40
  usernamePasswordConstraint.constant = -40
  passwordButtonConstraint.constant = -40
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    
    let duration = 0.5
    let delay = 0.1
    let damping = CGFloat(0.6)
    let springVelocity = CGFloat(0.0)

    labelTopConstraint.constant = 30
    UIView.animate(withDuration: duration,
                   delay: 0.0,
                   usingSpringWithDamping: damping,
                   initialSpringVelocity: springVelocity,
                   options: [],
                   animations: {
                    
                    self.view.layoutIfNeeded()
    }, completion:nil)

    labelUsernameConstraint.constant = 8
    UIView.animate(withDuration: duration,
                   delay: delay,
                   usingSpringWithDamping: damping,
                   initialSpringVelocity: springVelocity,
                   options: [],
                   animations: {
                    
                    self.view.layoutIfNeeded()
    }, completion: nil)

    usernamePasswordConstraint.constant = 8
    UIView.animate(withDuration: duration,
                   delay: delay*2,
                   usingSpringWithDamping: damping,
                   initialSpringVelocity: springVelocity,
                   options: [],
                   animations: {
                    
                    self.view.layoutIfNeeded()
    }, completion: nil)

    passwordButtonConstraint.constant = 8
    UIView.animate(withDuration: duration,
                   delay: delay*3,
                   usingSpringWithDamping: damping,
                   initialSpringVelocity: springVelocity,
                   options: [],
                   animations: {
                    
                    self.view.layoutIfNeeded()
    }, completion: nil)
}