swiftui中的validateJavaScript [英] evaluateJavaScript in swiftui

问题描述

从Webview收到消息后如何使评估JavaScript正常工作?

How to get evaluateJavaScript to work when a message is received from webview?

print(message.body)< ---工作正常

print(message.body) <--- this is working

parent?.evaluateJavaScript("document.getElementsByClassName('mat-toolbar-single-row')[0] .style.backgroundColor ='red'，completionHandler:nil)< ---这不是

parent?.evaluateJavaScript("document.getElementsByClassName('mat-toolbar-single-row')[0].style.backgroundColor = 'red'", completionHandler: nil) <--- this is not

struct WebView: UIViewRepresentable {

let request: URLRequest

let contentController = ContentController(nil)


func makeUIView(context: Context) -> WKWebView {
    let webConfiguration = WKWebViewConfiguration()
    let wkcontentController = WKUserContentController()
    wkcontentController.add(contentController, name: "test")
    webConfiguration.userContentController = wkcontentController
    return WKWebView(frame: .zero, configuration: webConfiguration)
}



func updateUIView(_ view: WKWebView, context: Context) {        
    view.load(request)
}

class ContentController: NSObject, WKScriptMessageHandler {
    var parent: WKWebView?
    init(_ parent: WKWebView?) {
        self.parent = parent
    }

    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage)  {
        if message.name == "test"{
            print(message.body)
            parent?.evaluateJavaScript("document.getElementsByClassName('mat-toolbar-single-row')[0].style.backgroundColor = 'red'", completionHandler: nil)

        }
    }
}

推荐答案

这里是可行的方法.由于我没有预期的测试环境，因此无法完全测试它，但是所有基础结构都正确构建.所以你可以尝试

Here is possible approach. As I don't have intended testing environment I could not test it completely, but all infrastructure constructed correctly. So you can try

struct WebView: UIViewRepresentable {

    let request: URLRequest

    func makeUIView(context: Context) -> WKWebView {
        let webConfiguration = WKWebViewConfiguration()
        let wkcontentController = WKUserContentController()

        wkcontentController.add(context.coordinator, name: "test")
        webConfiguration.userContentController = wkcontentController

        let webView = WKWebView(frame: .zero, configuration: webConfiguration)
        context.coordinator.parent = webView // inject as weak

        return webView
    }

    func updateUIView(_ view: WKWebView, context: Context) {
        if view.url == nil {
            view.load(request)
        }
    }

    func makeCoordinator() -> ContentController {
        ContentController() // let handler be a coordinator
    }

    class ContentController: NSObject, WKScriptMessageHandler {
        weak var parent: WKWebView? // weak to avoid reference cycling

        func userContentController(_ userContentController: WKUserContentController, 
                                   didReceive message: WKScriptMessage)  {
            if message.name == "test" {
                print(message.body)
                parent?.evaluateJavaScript("document.getElementsByClassName('mat-toolbar-single-row')[0].style.backgroundColor = 'red'", 
                    completionHandler: nil)

            }
        }
    }
}

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