SwiftUI coordinator not updating the containing view's property - swift

Question

So I've wrapped WKWebView in an UIViewRepresentable and built a coordinator in order to access its navigation delegate's functions. In the webView(_:didFinish:) function I am trying to update the view's didFinishLoading variable. If I print right after assigning, it prints true - the expected behavior. But, in the parent view, when I call the getHTML function, it prints false - even if I wait until the WKWebView is fully loaded.
Here is the code:
import SwiftUI
import WebKit
struct WebView: UIViewRepresentable {
#Binding var link: String
init(link: Binding<String>) {
self._link = link
}
private var didFinishLoading: Bool = false
let webView = WKWebView()
func makeUIView(context: UIViewRepresentableContext<WebView>) -> WKWebView {
self.webView.load(URLRequest(url: URL(string: self.link)!))
self.webView.navigationDelegate = context.coordinator
return self.webView
}
func updateUIView(_ uiView: WKWebView, context: UIViewRepresentableContext<WebView>) {
return
}
class Coordinator: NSObject, WKNavigationDelegate {
private var webView: WebView
init(_ webView: WebView) {
self.webView = webView
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
print("WebView: navigation finished")
self.webView.didFinishLoading = true
}
}
func makeCoordinator() -> WebView.Coordinator {
Coordinator(self)
}
func getHTML(completionHandler: #escaping (Any?) -> ()) {
print(self.didFinishLoading)
if (self.didFinishLoading) {
self.webView.evaluateJavaScript(
"""
document.documentElement.outerHTML.toString()
"""
) { html, error in
if error != nil {
print("WebView error: \(error!)")
completionHandler(nil)
} else {
completionHandler(html)
}
}
}
}
}
struct WebView_Previews: PreviewProvider {
#State static var link = "https://apple.com"
static var previews: some View {
WebView(link: $link)
}
}

Answer 1

Here is your code, a bit modified for demo, with used view model instance of ObservableObject holding your loading state.
import SwiftUI
import WebKit
import Combine
class WebViewModel: ObservableObject {
#Published var link: String
#Published var didFinishLoading: Bool = false
init (link: String) {
self.link = link
}
}
struct WebView: UIViewRepresentable {
#ObservedObject var viewModel: WebViewModel
let webView = WKWebView()
func makeUIView(context: UIViewRepresentableContext<WebView>) -> WKWebView {
self.webView.navigationDelegate = context.coordinator
if let url = URL(string: viewModel.link) {
self.webView.load(URLRequest(url: url))
}
return self.webView
}
func updateUIView(_ uiView: WKWebView, context: UIViewRepresentableContext<WebView>) {
return
}
class Coordinator: NSObject, WKNavigationDelegate {
private var viewModel: WebViewModel
init(_ viewModel: WebViewModel) {
self.viewModel = viewModel
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
print("WebView: navigation finished")
self.viewModel.didFinishLoading = true
}
}
func makeCoordinator() -> WebView.Coordinator {
Coordinator(viewModel)
}
}
struct WebViewContentView: View {
#ObservedObject var model = WebViewModel(link: "https://apple.com")
var body: some View {
VStack {
TextField("", text: $model.link)
WebView(viewModel: model)
if model.didFinishLoading {
Text("Finished loading")
.foregroundColor(Color.red)
}
}
}
}
struct WebView_Previews: PreviewProvider {
static var previews: some View {
WebViewContentView()
}
}