Separate Instances of Same Struct SwiftUI

Question

In the SwiftUI, how could I create two separate instances of the same struct? The purpose for this, in my case, is the following: I have an application written in the SwiftUI consisting of a tab bar. Each tab shows a different webpage. When I create the tab bar, for each tab object, I am currently passing a URLrequest as an argument of a struct. However, I have had to make a new struct with nearly the same code verbatum for each webpage/tab I want. When I try to just use the same struct, all tabs show the same webpage due to the first line of the struct:

static var cache = [URL: WKWebView]()

However, if I remove the static keyword, I just unresolvable errors. How can I do this successfully?

Ok, here's my continuation for the requested example. Here's the struct which controls the webview.

struct WebView : UIViewRepresentable {
    
    static var cache = [URL: WKWebView]()

    let request: URLRequest
    
    func makeUIView(context: Context) -> WKWebView  {
        guard let url = request.url else {fatalError()}

        if let webView = WebView.cache[url] {
            return webView
        }

        let webView = WKWebView()
        WebView.cache[url] = webView
        return webView
    }

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

Now here's the contentview:

struct ContentView: View {
    var body: some View {
        TabView {
            WebView(request: URLRequest(url: URL(string: "https://www.google.com")!)).edgesIgnoringSafeArea(.all).tabItem {
                VStack {
                    Text("Google")
                }
            }
            
            WebView(request: URLRequest(url: URL(string: "https://www.apple.com")!)).edgesIgnoringSafeArea(.all).tabItem {
                VStack {
                    Text("Apple")
                }
            }
        }
    }
}

However, this would cause both tabs to always show the same page. I clearly want them to show the urls specified. How might I accomplish this?

pawello2222 · Accepted Answer · 2020-07-01 20:06:19Z

1

Try the following:

struct ContentView: View {
    var body: some View {
        TabView {
            webView(url: "https://www.google.com")
                .edgesIgnoringSafeArea(.all)
                .tabItem {
                    VStack {
                        Text("Google")
                    }
                }
            webView(url: "https://www.apple.com")
                .edgesIgnoringSafeArea(.all)
                .tabItem {
                    VStack {
                        Text("Apple")
                    }
                }
        }
    }

    func webView(url: String) -> some View {
        WebView(request: URLRequest(url: URL(string: url)!))
    }
}

Note: instead of force-unwrapping URL(string: url)! you may want to provide a default url or a default view. Even if the site is valid it may not always be available.

answered Jul 1, 2020 at 20:06

pawello2222

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7 Comments

pawello2222 Over a year ago

Works for me - I tested it using Xcode 11.5, Swift 1.0. If it doesn't maybe it's because you're using Swift 2.0 beta. In that case you should specify it in the question.

user192361237 Over a year ago

I'm not sure how to check which version I'm using. How can I find this?

pawello2222 Over a year ago

@R12568asdb You can start with the Xcode version: Go to Xcode -> About Xcode

user192361237 Over a year ago

11.5 is my current Xcode version, but I knew that one

user192361237 Over a year ago

Ah, nevermind, there's just some unknown problem with the Mac. I just simulated it on my physical iPhone and it works great. Thanks!

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