swift - 如何将WKUIDelegate实现到SwiftUI WKWebView中？

我正在Xcode v11上创建一个Web应用程序，并且在实现WKUIDelegate来显示Javascript警报并在该Web应用程序上正确确认时遇到了麻烦。

我有一个非常简单的webview应用，在ContentView.swift上具有以下代码，但不确定如何使用此代码正确实现WKUIDelegate。

import SwiftUI
import WebKit

struct Webview : UIViewRepresentable {
    let request: URLRequest
    var webview: WKWebView?

    init(web: WKWebView?, req: URLRequest) {
        self.webview = WKWebView()
        self.request = req
    }

    func makeUIView(context: Context) -> WKWebView  {
        return webview!
    }

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

    func goBack(){
        webview?.goBack()
    }

    func goForward(){
        webview?.goForward()
    }

    func reload(){
        webview?.reload()
    }
}

struct ContentView: View {

    let webview = Webview(web: nil, req: URLRequest(url: URL(string: "https://google.com")!))

    var body: some View {
        VStack {
            webview
            HStack() {
                Button(action: {
                    self.webview.goBack()
                }){
                    Image(systemName: "chevron.left")
                }.padding(32)

                Button(action: {
                    self.webview.reload()
                }){
                    Image(systemName: "arrow.clockwise")
                }.padding(32)

                Button(action: {
                    self.webview.goForward()
                }){
                    Image(systemName: "chevron.right")
                }.padding(32)
            }.frame(height: 32)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

在此代码中实现WKUIDelegate的最佳方法是什么？因此，它将正确显示Javascript Alert和Confirm。

最佳答案

您需要使用Coordinator，然后遵循WKUIDelegate:

class Coordinator: NSObject, WKUIDelegate {
    var parent: Webview

    init(_ parent: Webview) {
        self.parent = parent
    }

    // Delegate methods go here
    func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping () -> Void) {
        // alert functionality goes here
    }
}

func makeCoordinator() -> Coordinator {
    Coordinator(self)
}

然后确保updateUIView(..)将uiDelegate设置为context.coordinator:

func updateUIView(_ uiView: WKWebView, context: Context) {
    uiView.uiDelegate = context.coordinator
    [...]
}

完整代码在这里:

import SwiftUI
import WebKit

struct Webview : UIViewRepresentable {
    let request: URLRequest
    var webview: WKWebView?

    init(web: WKWebView?, req: URLRequest) {
        self.webview = WKWebView()
        self.request = req
    }

    class Coordinator: NSObject, WKUIDelegate {
        var parent: Webview

        init(_ parent: Webview) {
            self.parent = parent
        }

        // Delegate methods go here

        func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping () -> Void) {
            // alert functionality goes here
        }
    }

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeUIView(context: Context) -> WKWebView  {
        return webview!
    }

    func updateUIView(_ uiView: WKWebView, context: Context) {
        uiView.uiDelegate = context.coordinator
        uiView.load(request)
    }

    func goBack(){
        webview?.goBack()
    }

    func goForward(){
        webview?.goForward()
    }

    func reload(){
        webview?.reload()
    }
}