A child web browser without navigation features in iOS using WKWebView in Swift

BasicChildBrowser.swift

import Foundation
import UIKit
import Webkit

class BasicChildBrowser:UIViewController, WKNavigationDelegate {
    let web = WKWebView()
    let toolbar = UIToolbar()
    let progressSpinner = UIActivityIndicatorView(activityIndicatorStyle: .White)
    let progressBar = UIProgressView(progressViewStyle: .Bar)

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        web.frame = CGRect(x: 0, y: 22, width: view.frame.width, height: view.frame.height-66)
        web.autoresizingMask = .FlexibleWidth | .FlexibleHeight
        web.navigationDelegate = self
        
        toolbar.frame = CGRect(x: 0, y: view.frame.height-44, width: view.frame.width, height: 44)
        toolbar.autoresizingMask = .FlexibleTopMargin | .FlexibleRightMargin | .FlexibleWidth
        
        progressSpinner.frame = CGRect(x: 0, y: 0, width: 30, height: 30)
        progressBar.frame = CGRect(x: 0, y: 20, width: view.frame.width, height: 2)
        progressBar.alpha = 0
        progressBar.tintColor = UIColor.redColor()
        progressBar.autoresizingMask = .FlexibleWidth

        var progress = UIBarButtonItem(customView: progressSpinner)
        var flex = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace, target: nil, action: nil)
        var close = UIBarButtonItem(barButtonSystemItem: .Done, target: self, action: "closeWebview")
        
        close.tintColor = UIColor.redColor()
        
        toolbar.setItems([progress,flex,close], animated: true)
        toolbar.barTintColor = UIColor.blackColor()
        toolbar.barStyle = UIBarStyle.Black
        
        view.addSubview(progressBar)
        view.addSubview(web)
        view.addSubview(toolbar)
        view.backgroundColor = UIColor.whiteColor()
    }
    
    func closeWebview(){
        dismissViewControllerAnimated(true, nil)
    }
    
    func loadURL(url:String) {
        web.loadRequest(NSURLRequest(URL: NSURL(string: url)))
    }
    
    func webView(webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation) {
        progressSpinner.startAnimating()
        self.progressBar.setProgress(0, animated: true)
        UIView.animateWithDuration(0.3, delay: 0, options: .CurveEaseInOut, animations: { self.progressBar.alpha = 1 }, nil)
        UIApplication.sharedApplication().networkActivityIndicatorVisible = true
    }
    
    func webView(webView: WKWebView, didCommitNavigation navigation: WKNavigation){
        progressBar.setProgress(webView.estimatedProgress.bridgeToObjectiveC().floatValue, animated: true)
    }
    
    func webView(webView: WKWebView, didFinishNavigation navigation: WKNavigation) {
        progressSpinner.stopAnimating()
        progressBar.setProgress(1, animated: true)
        UIView.animateWithDuration(0.3, delay: 1, options: .CurveEaseInOut, animations: { self.progressBar.alpha = 0 }, completion: nil)
        UIApplication.sharedApplication().networkActivityIndicatorVisible = false
    }
    
    func webView(webView: WKWebView, navigation: WKNavigation, withError error: NSError) {
        progressSpinner.stopAnimating()
        progressBar.setProgress(1, animated: true)
        UIView.animateWithDuration(0.3, delay: 1, options: .CurveEaseInOut, animations: { self.progressBar.alpha = 0 }, completion: nil)
        UIApplication.sharedApplication().networkActivityIndicatorVisible = false
        let alert:UIAlertController = UIAlertController(title: "Error", message: "Could not load webpage", preferredStyle: .Alert)
        alert.addAction(UIAlertAction(title: "OK", style: .Cancel, nil))
        
        presentViewController(alert, animated: true) {
            self.dismissViewControllerAnimated(true, nil)
        }
    }
    
    override func prefersStatusBarHidden() -> Bool {
        return false
    }
}

LICENSE

The MIT License (MIT)

Copyright (c) 2014 Aaron Rosenbaum

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.