AsyncImage. Cannot use switch statement in Phase closure?-CodePudding

When I use switch statement in phase in asyncImage it gave me this error.

Trailing closure passed to parameter of type 'CGFloat' that does not accept a closure

I understand that docs uses if let statements to extract the image and get the error like here down.

My code:

 AsyncImage(url: URL(string:stringURL)) { phase in
                switch phase {
                    case .empty:
                        ProgressView()
                    case .success(let image):
                        image
                          .scaledToFit()
                    case .failure():
                        EmptyView()
                    }
                  }

As per Apple Docs:

AsyncImage(url: URL(string: "https://example.com/icon.png")) { phase in
    if let image = phase.image {
      image // Displays the loaded image.
     } else if phase.error != nil {
    Color.red // Indicates an error.
      } else {
    Color.blue // Acts as a placeholder.
   }

My question is why I cannot use switch statement here. And what does this error means exactly?

Thanks.

CodePudding user response：

you can use a switch statement, use this, works for me:

case .failure(_):  // <-- here

Here is the code I used to show that my answer works:

struct ContentView: View {
    
    @State private var stringURL = "https://upload.wikimedia.org/wikipedia/commons/e/ef/Red-billed_gull,_Red_Zone,_Christchurch,_New_Zealand.jpg"
    
    var body: some View {
        AsyncImage(url: URL(string: stringURL)) { phase in
            switch phase {
            case .empty:
                ProgressView()
            case .success(let image):
                image.resizable().scaledToFit()
            case .failure(_):  // <-- here
                EmptyView()
            @unknown default:
                Image(systemName: "exclamationmark.icloud")
            }
        }
    }
    
}