Example layout code in playground

Playground.swift

//: Playground - noun: a place where people can play

import Foundation
import UIKit
import PlaygroundSupport

// Needs this settings first before using UIWebView to render web pages in Playground
// Also required to run Auto Layout
PlaygroundPage.current.needsIndefiniteExecution = true

/**
 Example 1: Auto Layout
 In a production application, you need to setup constraints when views are created, like `viewDidLoad()` or `init()`
 Make sure to set translatesAutoresizingMaskIntoConstraints to false immediately after you initialized subviews
 */
let view = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 600))
view.backgroundColor = UIColor.lightGray
PlaygroundPage.current.liveView = view

let menuBar = UIView()
menuBar.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(menuBar)
menuBar.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
menuBar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
menuBar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
menuBar.heightAnchor.constraint(equalToConstant: 64.0).isActive = true
menuBar.backgroundColor = UIColor.yellow

let toolbar = UIView()
toolbar.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(toolbar)
toolbar.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
toolbar.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
toolbar.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
toolbar.heightAnchor.constraint(equalToConstant: 64.0).isActive = true
toolbar.backgroundColor = UIColor.green

let webView = UIWebView()
webView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(webView)
webView.topAnchor.constraint(equalTo: menuBar.bottomAnchor, constant: 8.0).isActive = true
webView.bottomAnchor.constraint(equalTo: toolbar.topAnchor, constant: -8.0).isActive = true
webView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
webView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
webView.loadRequest(URLRequest(url: URL(string:"https://www.google.co.jp")!))

/**
 Example 2: Manual Layout
 In a production application, separate the initialization code of your subviews and layout code.
 Initializations should be done in viewDidLoad(), init() or something like that, but the manual layout has to be done within
 UIView.layoutSubviews() or UIViewController.viewDidLayoutSubviews().
 You can actually mix auto layout with manual layout but it causes too much confuses especially for unexperienced developers. You should avoid it
 unless you know exactly what you're doing.
 */
let view = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 600))
view.backgroundColor = UIColor.lightGray
PlaygroundPage.current.liveView = view

let menuBar = UIView()
view.addSubview(menuBar)
menuBar.frame = CGRect(x: view.frame.minX, y: view.frame.minY, width: view.frame.width, height: 64.0)
menuBar.backgroundColor = UIColor.yellow

let toolbar = UIView()
view.addSubview(toolbar)
toolbar.frame = CGRect(x: view.frame.minX, y: view.frame.maxY-64.0, width: view.frame.width, height: 64.0)
toolbar.backgroundColor = UIColor.green

let webView = UIWebView()
view.addSubview(webView)
webView.frame = CGRect(x: view.frame.minX,
                       y: menuBar.frame.maxY+8.0,
                       width: view.frame.width,
                       height: view.frame.height - menuBar.frame.height - toolbar.frame.height - 16.0)
webView.loadRequest(URLRequest(url: URL(string:"https://www.google.co.jp")!))