UIWebView and JavaScriptInterface in Swift - ios

Question

How can I to create the JavascriptInterface channel from my web site to my UIWebView?
Example in Android:
webView.addJavascriptInterface(new WebAppInterface(this), "Android");
And from this JavascriptInterface I would like to draw the methods, as for example:
func webViewDidStartLoad(webView: UIWebView)
or
myActivityIndicator.startAnimating()
How can I do?

Answer 1

For WKWebView: source here
JavaScript
function callNativeApp () {
try {
webkit.messageHandlers.callbackHandler.postMessage("Hello from JavaScript");
} catch(err) {
console.log('The native context does not exist yet');
}
}
Swift
import WebKit
class ViewController: UIViewController, WKScriptMessageHandler {
#IBOutlet var containerView: UIView? = nil
var webView: WKWebView?
override func loadView() {
super.loadView()
let contentController = WKUserContentController()
contentController.addScriptMessageHandler(self, name: "callbackHandler")
let config = WKWebViewConfiguration()
config.userContentController = contentController
self.webView = WKWebView( frame: self.containerView!.bounds, configuration: config)
self.view = self.webView
}
override func viewDidLoad() {
super.viewDidLoad()
//I use the file html in local
let path = NSBundle.mainBundle().pathForResource("index", ofType: "html")
let url = NSURL(fileURLWithPath: path!)
let req = NSURLRequest(URL: url)
self.webView!.loadRequest(req)
}
func userContentController(userContentController: WKUserContentController, didReceiveScriptMessage message: WKScriptMessage) {// edit: changed fun to func
if (message.name == "callbackHandler"){
print("\(message.body)")
}
}
}
For UIWebView: source here
JavaScript in HTML
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script>
(function(){
$(window).load(function(){
$('.clickMe').on('click', function(){
window.location = "foobar://fizz?Hello_from_javaScript";
});
});
})(jQuery);
</script>
Swift
import UIKit
class ViewController: UIViewController, UIWebViewDelegate {
#IBOutlet weak var Web: UIWebView!
override func viewDidLoad() {
super.viewDidLoad()
let path = NSBundle.mainBundle().pathForResource("index", ofType: "html")
let url = NSURL(fileURLWithPath: path!)
let req = NSURLRequest(URL: url)
Web.delegate = self
Web.loadRequest(req)
}
func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
if request.URL?.query != nil {
print("\(request.URL!.query!)")
}
return true
}
}

Answer 2

Here's a quick example:
Register a URL Scheme such as foobar in Xcode
Handle this URL Scheme in your web view
func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
if request.URL?.query?.containsString("show_activity_indicator=true") {
myActivityIndicator.startAnimating()
}
}
Finally, call this from your JavaScript
// Show your activity indicator from JavaScript.
window.location = "foobar://fizz?show_activity_indicator=true"
Note: See my question here for more information on web view communication in iOS.