dismiss

Discussion 議論

Use this environment value to get the DismissAction instance for the current Environment. Then call the instance to perform the dismissal. You call the instance directly because it defines a callAsFunction() method that Swift calls when you call the instance.

For example, you can create a button that calls the DismissAction:

private struct SheetContents: View {
    @Environment(\.dismiss) private var dismiss


    var body: some View {
        Button("Done") {
            dismiss()
        }
    }
}

If you present the SheetContents view in a sheet, the user can dismiss the sheet by tapping or clicking the sheet’s button:

private struct DetailView: View {
    @State private var isSheetPresented = false


    var body: some View {
        Button("Show Sheet") {
            isSheetPresented = true
        }
        .sheet(isPresented: $isSheetPresented) {
            SheetContents()
        }
    }
}

Be sure that you define the action in the appropriate environment. For example, don’t reorganize the DetailView in the example above so that it creates the dismiss property and calls it from the sheet(item:onDismiss:content:) view modifier’s content closure:

private struct DetailView: View {
    @State private var isSheetPresented = false
    @Environment(\.dismiss) private var dismiss // Applies to DetailView.


    var body: some View {
        Button("Show Sheet") {
            isSheetPresented = true
        }
        .sheet(isPresented: $isSheetPresented) {
            Button("Done") {
                dismiss() // Fails to dismiss the sheet.
            }
        }
    }
}

If you do this, the sheet fails to dismiss because the action applies to the environment where you declared it, which is that of the detail view, rather than the sheet. In fact, if you’ve presented the detail view in a NavigationView, the dismissal pops the detail view the navigation stack.

The dismiss action has no effect on a view that isn’t currently presented. If you need to query whether SwiftUI is currently presenting a view, read the isPresented environment value.