UIScrollView example, with a textfield that's not covered when the keyboard appears, fully programmatic with AutoLayout. Swift 4.0

ScrollViewExample+TextField.swift

//
//  ViewController.swift
//  Repnote
//
//  Created by John Neumann on 05/07/2017.
//  Copyright © 2017 Audioy. All rights reserved.
//

import UIKit

class ViewController: UIViewController {
    
    fileprivate var activeField: UITextField?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.white
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
        addSubviewsAndSetupContraints()
    }
    
    deinit {
        NotificationCenter.default.removeObserver(self)
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        view.layoutIfNeeded() // Give the containerView a size
        scrollView.contentSize = containerView.bounds.size // Set the content size to that of the container
    }
    
    // UI
    fileprivate lazy var scrollView: UIScrollView = {
        let sv = UIScrollView(frame: .zero)
        self.automaticallyAdjustsScrollViewInsets = false // Set as false or there will be padding above the container view
        sv.contentInset = .zero // ScrollViews have insets naturally - remove them
        sv.backgroundColor = UIColor.green
        return sv
    }()
    
    fileprivate lazy var containerView: UIView = {
        let v = UIView()
        v.backgroundColor = UIColor.red
        return v
    }()
    
    fileprivate lazy var testTextField: UITextField = {
        let tf = UITextField()
        tf.backgroundColor = UIColor.white
        tf.placeholder = "HELLO WORLD"
        tf.delegate = self
        return tf
    }()
    
}

extension ViewController: AutoLayoutType{
    func addSubviewsAndSetupContraints() {
        containerView.addSubview(testTextField)
        scrollView.addSubview(containerView)
        view.addSubview(scrollView)
        
        NSLayoutConstraint.useAndActivate([
            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
            scrollView.leftAnchor.constraint(equalTo: view.leftAnchor),
            scrollView.rightAnchor.constraint(equalTo: view.rightAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
            ])
        
        NSLayoutConstraint.useAndActivate([
            containerView.topAnchor.constraint(equalTo: scrollView.topAnchor),
            containerView.leftAnchor.constraint(equalTo: scrollView.leftAnchor),
            containerView.widthAnchor.constraint(equalTo: view.widthAnchor), // The scrollView fits its content, so set the width to that of the view
            containerView.bottomAnchor.constraint(equalTo: testTextField.bottomAnchor, constant: 30) // Set to the bottom of the last element
            ])
        
        NSLayoutConstraint.useAndActivate([
            testTextField.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            testTextField.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 900)
            ])
    }
}

extension ViewController: UITextFieldDelegate{
    
    func textFieldDidBeginEditing(_ textField: UITextField) {
        activeField = textField
    }
    func textFieldDidEndEditing(_ textField: UITextField) {
        activeField = nil
    }
    
    func textFieldShouldReturn(_ textField: UITextField) -> Bool{
        textField.resignFirstResponder()
        return false
    }
    
    // Automatically adjust the scroll view IF the keyboard covers the textfield
    @objc fileprivate func keyboardWillShow(notification: NSNotification) {
        
        if  let userInfo = notification.userInfo,
            let keyboardSize = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue,
            let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue,
            let animationCurveRaw = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
        {
            let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: UIViewAnimationOptions.RawValue(truncating: animationCurveRaw))
            let contentInsets : UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize.height, 0.0)
            
            UIView.animate(withDuration: duration, delay: 0, options: animationCurve, animations: {
                self.scrollView.contentInset = contentInsets
                self.scrollView.scrollIndicatorInsets = contentInsets
                
                var aRect : CGRect = self.view.frame
                aRect.size.height -= keyboardSize.height
                if let activeField = self.activeField {
                    if (!aRect.contains(activeField.frame.origin)){
                        self.scrollView.scrollRectToVisible(activeField.frame, animated: false)
                    }
                }
            }, completion: nil)
        }
    }
    
    @objc fileprivate func keyboardWillHide(notification: NSNotification) {
        
        if  let userInfo = notification.userInfo,
            let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue,
            let animationCurveRaw = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
        {
            let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: UIViewAnimationOptions.RawValue(truncating: animationCurveRaw))
            
            UIView.animate(withDuration: duration, delay: 0, options: animationCurve, animations: {
                self.scrollView.contentInset = .zero
                self.scrollView.scrollIndicatorInsets = .zero
                self.view.endEditing(true)
            }, completion: nil)
        }
        
        
    }
}