callAsFunction(contentType:prepareDocument:)

Declaration

@MainActor @preconcurrency func callAsFunction(contentType: UTType, prepareDocument: @escaping (ModelContext) -> Void)

Parameters

• contentType:

  The content type of the document.

• prepareDocument:

  The closure that accepts ModelContext associated with the new document. Use this closure to set the document’s initial contents before it is displayed: insert preconfigured models in the provided ModelContext.

Discussion

Don’t call this method directly. SwiftUI calls it when you call the newDocument action.

For example, a Todo app might have a way to create a sample prepopulated Todo list as a part of onboarding experience:

newDocument(contentType: .todoList) { modelContext in
    let todoList = TodoList(
        title: "🎬 Movie night",
        items: [
            TodoItem(title: "🍿 Buy popcorn"),
            TodoItem(title: "🍨 Make some ice cream",
            TodoItem(title: "💡 Hang a string of lights")
        ]
    )
    modelContext.insert(todoList)
}

For information about how Swift uses the callAsFunction() method to simplify call site syntax, see Methods with Special Names in The Swift Programming Language.

See Also

Calling the action

• callAsFunction(_:)
• callAsFunction(contentType:)