使用wkwebview更改观察值
我正在为我的应用使用wkwebview。加载视图时，我想在本机上显示得分，而不是在wkwebview中显示。我使用组合框架工作来创建observableObject，以便在wkwebview中的分数更改时将我的分数显示给视图和其他视图。 。我使用window。我这样做是通过调用JS函数，该函数将消息发送到本机side ，并将已发送的分数分配给我的webkit.messagehandlers.bridge.postmessage（“ 0”）obseved> obsevedObject < /代码>。问题在本地。 USERCONTENTCONTROLLER函数，从wkwebview中处理消息，不断打印出分数并将分数重新分配给我的obsevedObject。它似乎被困在一个循环中。我提供了以下代码的简化版本。已经被困了几天了，似乎无法解决问题。
//Holds the score
class Myscore:ObservableObject{
@Published var score = "0"
}
//Wkwebview
struct WebView: UIViewRepresentable {
@ObservedObject var myScore : Myscore
class Coordinator: NSObject, WKNavigationDelegate, WKScriptMessageHandler {
var webView: WKWebView?
var myScore: Myscore
init(myScore:Myscore) {
self.myScore = myScore
super.init()
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
self.webView = webView
}
// receive message from wkwebview
func userContentController(
_ userContentController: WKUserContentController,
didReceive message: WKScriptMessage
) {
// This is where the issue occurs
var newscore = message.body as! String
myScore.score = newscore
print(myScore.score)
}
}
func makeCoordinator() -> Coordinator {
return Coordinator(myScore:myScore)
}
func makeUIView(context: Context) -> WKWebView {
let coordinator = makeCoordinator()
let userContentController = WKUserContentController()
userContentController.add(coordinator, name: "bridge")
let configuration = WKWebViewConfiguration()
configuration.userContentController = userContentController
let _wkwebview = WKWebView(frame: .zero, configuration: configuration)
_wkwebview.navigationDelegate = coordinator
return _wkwebview
}
func updateUIView(_ webView: WKWebView, context: Context) {
guard let path: String = Bundle.main.path(forResource: "index", ofType: "html")
else { return }
let localHTMLUrl = URL(fileURLWithPath: path, isDirectory: false)
webView.loadFileURL(localHTMLUrl, allowingReadAccessTo: localHTMLUrl)
}
}
//Content View to display the Score
struct ContentView: View {
@StateObject var myScore = Myscore()
var body: some View {
VStack {
Text("Your Score is\( myScore.score)")
WebView(myScore: myScore)
}
}
}
在这里编辑是HTML侧：
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, height=device-height, initial-scale=1, minimum-scale=1, viewport-fit=cover">
</head>
<body>
<button>click me</button>
<hr/>
<div id="log"></div>
<script>
window.onload = function () {
webkit.messageHandlers.bridge.postMessage("98 points")
}
</script>
</body>
</html>
编辑2：这是控制台打印的内容
I am using WkWebView for my app. When the view is loaded I would like to display the score Natively and not in the WkWebView. I used the combine Frame work to create an ObservableObject in order to display my score to the view and other views when the score changes in the WkWebview. I use window.onload to get the most recent score and display it when the page first renders. I do so by calling a JS function which sends a message to the Native side webkit.messageHandlers.bridge.postMessage("0") with the score and assign the sent score to my ObservedObject. The issue is on the Native side. The UserContentController function, which handles the message from the WkWebview, keeps printing out the score and reassigning the score to my ObservedObject. It seems to be stuck in a loop. I provided a simplified version of the code below. Have been stuck on this for a few days now and cant seem to fix the issue.
//Holds the score
class Myscore:ObservableObject{
@Published var score = "0"
}
//Wkwebview
struct WebView: UIViewRepresentable {
@ObservedObject var myScore : Myscore
class Coordinator: NSObject, WKNavigationDelegate, WKScriptMessageHandler {
var webView: WKWebView?
var myScore: Myscore
init(myScore:Myscore) {
self.myScore = myScore
super.init()
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
self.webView = webView
}
// receive message from wkwebview
func userContentController(
_ userContentController: WKUserContentController,
didReceive message: WKScriptMessage
) {
// This is where the issue occurs
var newscore = message.body as! String
myScore.score = newscore
print(myScore.score)
}
}
func makeCoordinator() -> Coordinator {
return Coordinator(myScore:myScore)
}
func makeUIView(context: Context) -> WKWebView {
let coordinator = makeCoordinator()
let userContentController = WKUserContentController()
userContentController.add(coordinator, name: "bridge")
let configuration = WKWebViewConfiguration()
configuration.userContentController = userContentController
let _wkwebview = WKWebView(frame: .zero, configuration: configuration)
_wkwebview.navigationDelegate = coordinator
return _wkwebview
}
func updateUIView(_ webView: WKWebView, context: Context) {
guard let path: String = Bundle.main.path(forResource: "index", ofType: "html")
else { return }
let localHTMLUrl = URL(fileURLWithPath: path, isDirectory: false)
webView.loadFileURL(localHTMLUrl, allowingReadAccessTo: localHTMLUrl)
}
}
//Content View to display the Score
struct ContentView: View {
@StateObject var myScore = Myscore()
var body: some View {
VStack {
Text("Your Score is\( myScore.score)")
WebView(myScore: myScore)
}
}
}
Edit here is the html side:
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, height=device-height, initial-scale=1, minimum-scale=1, viewport-fit=cover">
</head>
<body>
<button>click me</button>
<hr/>
<div id="log"></div>
<script>
window.onload = function () {
webkit.messageHandlers.bridge.postMessage("98 points")
}
</script>
</body>
</html>
Edit 2: This is what the console prints out
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等等来查看周期加载。
在这里，我可以
通过更新
myScore进行updateUiview调用 13.4 / iOS 15.5Here I see cycle loading by updating
Myscorewhich result inupdateUIViewcall and so forth...Initial loading should be placed into
makeUIViewTested with Xcode 13.4 / iOS 15.5
得分应为@binding和updateUiview将在更改时自动调用。不幸的是，这是Swiftui结构的众多无证件魔术行为之一。FYI
observableObject旨在将组合管道分配给@published。尝试坚持数据的结构，并使用@State和@binding以使您的值类型具有参考类型语义。scoreshould be@BindingandupdateUIViewwill be called automatically when it changes. Unfortunately this is one of the many undocumented magic behaviours of SwiftUI's structs.FYI
ObservableObjectis designed to assign a Combine pipeline to an@Published. Try and stick to structs for your data and use@Stateand@Bindingto make your value types have reference type semantics.