I want to pass JavaScript variable to Swift. I get an error in JavaScript & search for that but I didn't get any result. The error is:
TypeError: Cannot read property 'messageHandlers' of undefined
Any one can help?
My code in Xcode:
import UIKit
import WebKit
class ViewController: UIViewController,WKScriptMessageHandler,WKNavigationDelegate {
var webView = WKWebView()
override func viewDidLoad() {
super.viewDidLoad()
webView.frame = view.bounds
webView.navigationDelegate = self
let url = URL(string: "MyUrl")!
let urlRequest = URLRequest(url: url)
webView.load(urlRequest)
webView.autoresizingMask = [.flexibleWidth,.flexibleHeight]
view.addSubview(webView)
let userContentController = WKUserContentController()
userContentController.add(self, name: "test")
}
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
print("Name: \(message.name)")
print("Body: \(message.body as! String)")
}
}
And in JavaScript:
click: event => {
window.webkit.messageHandlers.test.postMessage("hi");
}
After adding the "test" message handler, you need to add it to your webView , but you're not doing that.
By including this message handler in your WKUserContentController object, your webview will define a new function window.webkit.messageHandlers.name.postMessage(messageBody) that can be called in all frames.
Try changing your viewDidLoad() to the following:
override func viewDidLoad() { super.viewDidLoad() let config = WKWebViewConfiguration() let userContentController = WKUserContentController() userContentController.add(self, name: "test") config.userContentController = userContentController webView = WKWebView(frame: view.bounds, configuration: config) // Create webView with the configuration webView.navigationDelegate = self let url = URL(string: "MyUrl")! let urlRequest = URLRequest(url: url) webView.load(urlRequest) webView.autoresizingMask = [.flexibleWidth,.flexibleHeight] view.addSubview(webView) }