How to call javascript function from .js file in swift
I tried to call a Javascript function from swift using below code but can't access the Javascript function
This is how I create the Javascript context object:
lazy var context: JSContext? = {
let context = JSContext()
guard let
JSPath = Bundle.main.path(forResource: "IAV", ofType: "html")
else {
print("Unable to read resource files.")
return nil
}
do {
let iav = try String(contentsOfFile: JSPath, encoding: String.Encoding.utf8)
_ = context?.evaluateScript(iav)
} catch (let error) {
print("Error while processing script file: \(error)")
}
return context
}()
//Set value to js
func setToken(Token:String)
{
let jsmethod = context?.objectForKeyedSubscript("setIAVToken")
let passParameter = jsmethod?.call(withArguments: [Token])
}
The content of html file is
sample IAV form
</head> <body > <header> </header> <main> <h1>Registration Form</h1> <form id="myform" method="post"> <div id="mainContainer"> <input type="button" id="start" value="Add Bank"> </div>var value="dhjhsd";
var setIAVToken = function(token) { value= token; } $('#start').click(function() { var iavToken = value; alert(iavToken) dwolla.configure('uat'); dwolla.iav.start('iavContainer', iavToken, function(err, res) { console.log('Error: ' + JSON.stringify(err) + ' -- Response: ' + JSON.stringify(res)); }); }); </script> </html>
Answer
You should probably use WKWebView (which is the new way to load web content in a webview in iOS since it uses WebKit and has lots of improvements like better memory allocation than it does WebView).
In a swift file WebviewBridging.swift in iOS you could have something like
import UIKit
import WebKit
class WebviewBridging: UIViewController, WKNavigationDelegate {
var webView: WKWebView?
override func viewDidLoad() {
super.viewDidLoad()
// Create a WKWebView instance
webView = WKWebView (frame: self.view.frame, configuration: webConfig)
view.addSubview(webView!)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let url = Bundle.main.url(forResource: "index", withExtension: "html")!
webView!.loadFileURL(url, allowingReadAccessTo: url)
}
func callJSFunctionFromSwift(){
webView!.evaluateJavaScript("changeBackgroundColor('red')", completionHandler: nil)
}
}
In an index.html file on your iOS project folder you could have something like:
<html>
<head>
</head>
<body>
<script>
function changeBackgroundColor(colorText) {
document.body.style.background = colorText;
}
</script>
</body>
</html>
Whenever you will call callJSFunctionFromSwift() in swift it will communicate with the WKWebView through XPC communication and evaluate your javascript code that will trigger the javascript function in index.html.