This has only just come up in Xcode 12 and iOS 14. I have an enum that determines which sheet to display. However, when I choose an option it does not update the view to show the correct view within the sheet.

As an example, the code below will show the first view as it is the default value. However, if the third view is selected from the buttons, the first view will display regardless. The console says the enum has updated, but it appears the view is not updated. Strangely, the issue occurs until you choose any other options than the first one you select...

Just an Xcode 12 bug or something I've done? Same issue occurs in both the simulator and on device.

Any help is greatly appreciated.

struct ContentView: View
{
    @State var showView : ViewDecider = .first
    @State var showSheet : Bool = false

    var body: some View
    {
        VStack(spacing: 30)
        {
            Button("Show First")
            {
                showView = .first
                showSheet.toggle()
                print(showView)
            }

            Button("Show Second")
            {
                showView = .second
                showSheet.toggle()
                print(showView)
            }

            Button("Show Third")
            {
                showView = .third
                showSheet.toggle()
                print(showView)
            }
        }.sheet(isPresented: $showSheet, content:
        {
            if showView == .first
            {
                Text("First")
            }
            else if showView == .second
            {
                Text("Second")
            }
            else
            {
                Text("Third")
            }
        })
    }
}

enum ViewDecider
{
    case first
    case second
    case third
}

I've applied the Hacking With Swift sample to show a second example..

struct ContentView: View
{
    @State var loadingState : LoadingState = .loading
    @State var showSheet : Bool = false

    enum LoadingState
    {
        case loading, success, failed
    }

    var body: some View
    {
        VStack(spacing: 30)
        {
            Button("Loading")
            {
                loadingState = .loading
                showSheet.toggle()
                print(loadingState)
            }

            Button("Success")
            {
                loadingState = .success
                showSheet.toggle()
                print(loadingState)
            }

            Button("Failed")
            {
                loadingState = .failed
                showSheet.toggle()
                print(loadingState)
            }
        }.sheet(isPresented: $showSheet, content:
        {
            Group
            {
                if loadingState == .loading {
                    LoadingView()
                } else if loadingState == .success {
                    SuccessView()
                } else if loadingState == .failed {
                    FailedView()
                }
            }
        })
    }
}

struct LoadingView: View {
    var body: some View {
        Text("Loading...")
    }
}

struct SuccessView: View {
    var body: some View {
        Text("Success!")
    }
}

struct FailedView: View {
    var body: some View {
        Text("Failed.")
    }
}

Same issue with a Bool, when you tap on Success you get the Loading view. Unless you tap on Loading then Success you continue to see the loading view.

struct ContentView: View
{
    @State var loading : Bool = true
    @State var showSheet : Bool = false

    var body: some View
    {
        VStack(spacing: 30)
        {
            Button("Loading")
            {
                loading = true
                showSheet.toggle()
                print(loading)
            }

            Button("Success")
            {
                loading = false
                showSheet.toggle()
                print(loading)
            }

        }.sheet(isPresented: $showSheet, content:
        {
            Group
            {
                if loading
                {
                    LoadingView()
                } else
                {
                    SuccessView()
                }
            }
        })
    }
}

struct LoadingView: View {
    var body: some View {
        Text("Loading...")
    }
}

struct SuccessView: View {
    var body: some View {
        Text("Success!")
    }
}

Thank you! I have zero idea why this has changed, assuming it is intentional. One less variable isn't a bad thing I suppose. The solution has broken the cancel button to the mail sheet via a UIRepresentable but I'll have a play. Thanks again.