Contents

alert(_:item:actions:message:)

Presents an alert with a message using the given data to produce the alert’s content and a localized string key for a title.

Declaration

nonisolated func alert<A, M, T>(_ titleKey: LocalizedStringKey, item data: Binding<T?>, @ContentBuilder actions: (T) -> A, @ContentBuilder message: (T) -> M) -> some View where A : View, M : View

Parameters

  • titleKey:

    The key for the localized string that describes the title of the alert.

  • data:

    A binding to optional source of truth for the alert. The system presents the alert when the binding’s value is non-nil. When the user presses or taps one of the alert’s actions, the system sets this value to nil and dismisses. The system passes the contents to the modifier’s closures. You use this data to populate the fields of an alert that you create that the system displays to the user.

  • actions:

    A Contentbuilder returning the alert’s actions given the currently available data.

  • message:

    A Contentbuilder returning the message for the alert given the currently available data.

Discussion

For the alert to appear, data must not be nil. The data should not change after the presentation occurs. Any changes that you make after the presentation occurs are ignored.

Use this method when you need to populate the fields of an alert with content from a data source. The example below shows a custom data source, SaveDetails, that provides data to populate the alert:

struct SaveDetails: Identifiable {
    let name: String
    let error: String
    let id = UUID()
}

struct SaveButton: View {
    @State private var details: SaveDetails?

    var body: some View {
        Button("Save") {
            details = model.save(didError: $didError)
        }
        .alert(
            "Save failed.",
            item: $details
        ) { details in
            Button(role: .destructive) {
                // Handle the deletion.
            } label: {
                Text("Delete \(details.name)")
            }
            Button("Retry") {
                // Handle the retry action.
            }
        } message: { details in
            Text(details.error)
        }
    }
}

This modifier creates a Text view for the title on your behalf, and treats the localized key similar to init(_:tableName:bundle:comment:). See Text for more information about localizing strings.

All actions in an alert dismiss the alert after the action runs. The default button is shown with greater prominence. You can influence the default button by assigning it the defaultAction keyboard shortcut.

The system may reorder the buttons based on their role and prominence.

If no actions are present, the system includes a standard “OK” action. No default cancel action is provided. If you want to show a cancel action, use a button with a role of cancel.

On iOS, tvOS, and watchOS, alerts only support controls with labels that are Text. Passing any other type of view results in the content being omitted.

Only unstyled text is supported for the message.

See Also

Presenting an alert