How to Migrate to WKWebView

Question

I m trying to understand how to make use of the new WKWebView in iOS8  can t find much information  I ve read   http   developer telerik com featured why-ios-8s-wkwebview-is-a-big-deal-for-hybrid-development  http   nshipster com wkwebkit   But how does this affect existing apps  Will an ordinary UiWebView get the speedup from the nitro java script engine or do we need to make changes  How do we deal with backwards compatibility   All the code and examples I can find are using swift  will this be mandatory   Thankful for any help on this matter

User · Answer

Swift 4      let webView   WKWebView        Set Frame as per requirment  I am leaving it for you     let url   URL string   http   www google com        webView load URLRequest url  url       view addSubview webView

User · Answer

Here is how I transitioned from UIWebView to WKWebView       Note  There is no property like UIWebView that you can drag onto your   storyboard  you have to do it programatically    Make sure you import WebKit WebKit h into your header file    This is my header file    import  lt WebKit WebKit h gt    interface ViewController   UIViewController   property strong nonatomic  WKWebView  webView   property  strong  nonatomic  NSString  productURL    end   Here is my implementation file    import  ViewController h    interface ViewController      end    implementation ViewController  -  void viewDidLoad        super viewDidLoad       self productURL     http   www URL YOU WANT TO VIEW GOES HERE        NSURL  url    NSURL URLWithString self productURL       NSURLRequest  request    NSURLRequest requestWithURL url         webView     WKWebView alloc  initWithFrame self view frame           webView loadRequest request        webView frame   CGRectMake self view frame origin x self view frame origin y  self view frame size width  self view frame size height        self view addSubview  webView      -  void didReceiveMemoryWarning        super didReceiveMemoryWarning          Dispose of any resources that can be recreated      end

User · Answer

You have to use WKWebView  which is available as of iOS8 in Framework  WebKit  to get the speedup  If you need backwards compatibility  you have to use UIWebView for iOS7 and older   I set up a little code to provide the UIViewController frame for the new WKWebView  It can be installed via cocoapods  Have a look here   STKWebKitViewController on github

User · Answer

UIWebView will still continue to work with existing apps  WKWebView is available starting from iOS8  only WKWebView has a Nitro JavaScript engine    To take advantage of this faster JavaScript engine in older apps you have to make code changes to use WKWebView instead of UIWebView  For iOS7 and older  you have to continue to use UIWebView  so you may have to check for iOS8 and then apply WKWebView methods   delegate methods and fallback to UIWebView methods for iOS7 and older  Also there is no Interface Builder component for WKWebView  yet   so you have to programmatically implement WKWebView   You can implement WKWebView in Objective-C  here is simple example to initiate a WKWebView   WKWebViewConfiguration  theConfiguration     WKWebViewConfiguration alloc  init   WKWebView  webView     WKWebView alloc  initWithFrame self view frame configuration theConfiguration   webView navigationDelegate   self  NSURL  nsurl  NSURL URLWithString   http   www apple com    NSURLRequest  nsrequest  NSURLRequest requestWithURL nsurl    webView loadRequest nsrequest    self view addSubview webView     WKWebView rendering performance is noticeable in WebGL games and something that runs complex JavaScript algorithms  if you are using webview to load a simple html or website  you can continue to use UIWebView    Here is a test app that can used to open any website using either UIWebView or WKWebView and you can compare performance  and then decide on upgrading your app to use WKWebView  https   itunes apple com app id928647773 mt 8 amp at 10ltWQ

User · Answer

Swift is not a requirement  everything works fine with Objective-C  UIWebView will continue to be supported  so there is no rush to migrate if you want to take your time  However  it will not get the javascript and scrolling performance enhancements of WKWebView   For backwards compatibility  I have two properties for my view controller  a UIWebView and a WKWebView  I use the WKWebview only if the class exists   if   WKWebView class            do new webview stuff   else          do old webview stuff     Whereas I used to have a UIWebViewDelegate  I also made it a WKNavigationDelegate and created the necessary methods

User · Answer

WKWebView using Swift in iOS 8    The whole ViewController swift file now looks like this   import UIKit import WebKit  class ViewController  UIViewController         IBOutlet var containerView   UIView    nil     var webView  WKWebView       override func loadView             super loadView            self webView   WKWebView           self view   self webView             override func viewDidLoad             super viewDidLoad            var url   NSURL string  http   www kinderas com            var req   NSURLRequest URL url          self webView  loadRequest req             override func didReceiveMemoryWarning             super didReceiveMemoryWarning

User · Answer

Step   1 Import webkit in ViewController swift  import WebKit   Step   2 Declare variable of webView   var webView   WKWebView    Step   3 Adding Delegate of WKNavigationDelegate  class ViewController  UIViewController   WKNavigationDelegate    Step   4 Adding code in ViewDidLoad   let myBlog    https   iosdevcenters blogspot com   let url   NSURL string  myBlog  let request   NSURLRequest URL  url       init and load request in webview  webView   WKWebView frame  self view frame  webView navigationDelegate   self webView loadRequest request  self view addSubview webView  self view sendSubviewToBack webView    Step   5 Edit the info plist adding    lt dict gt   lt key gt NSAllowsArbitraryLoads lt  key gt   lt true  gt   lt key gt NSExceptionDomains lt  key gt   lt dict gt   lt key gt google com lt  key gt   lt dict gt       lt key gt NSExceptionAllowsInsecureHTTPLoads lt  key gt       lt true  gt       lt key gt NSIncludesSubdomains lt  key gt       lt true  gt   lt  dict gt   lt  dict gt

User · Answer

WkWebView is much faster and reliable than UIWebview according to the Apple docs   Here  I posted my WkWebViewController   import UIKit import WebKit  class WebPageViewController  UIViewController UINavigationControllerDelegate UINavigationBarDelegate WKNavigationDelegate       var webView  WKWebView      var webUrl  http   www nike com       override func viewWillAppear animated  Bool           super viewWillAppear true          navigationController  navigationBar hidden   false            override func viewDidLoad                    Create our preferences on how the web page should be loaded            let preferences   WKPreferences           preferences javaScriptEnabled   false             Create a configuration for our preferences            let configuration   WKWebViewConfiguration           configuration preferences   preferences             Now instantiate the web view            webView   WKWebView frame  view bounds  configuration  configuration           if let theWebView   webView                 Load a web page into our web view                let url   NSURL string  self webUrl              let urlRequest   NSURLRequest URL  url               theWebView loadRequest urlRequest              theWebView navigationDelegate   self             view addSubview theWebView                            Start the network activity indicator when the web view is loading        func webView webView  WKWebView didStartProvisionalNavigation navigation  WKNavigation               UIApplication sharedApplication   networkActivityIndicatorVisible   true               Stop the network activity indicator when the loading finishes        func webView webView  WKWebView didFinishNavigation navigation  WKNavigation               UIApplication sharedApplication   networkActivityIndicatorVisible   false            func webView webView  WKWebView          decidePolicyForNavigationResponse navigationResponse  WKNavigationResponse decisionHandler    WKNavigationResponsePolicy  - gt  Void                  print navigationResponse response MIMEType              decisionHandler  Allow             override func didReceiveMemoryWarning            super didReceiveMemoryWarning

User · Answer

Use some design patterns  you can mix UIWebView and WKWebView  The key point is to design a unique browser interface  But you should pay more attention to your app s current functionality  for example  if your app using NSURLProtocol to enhance network ability  using WKWebView you have no chance to do the same thing  Because NSURLProtocol only effects the current process  and WKWebView using  muliti-process architecture  the networking staff is in a seperate process

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