ReadableDocument

protocol · iOS 27.0+ · SDK 27.1

protocol ReadableDocument : AnyObject

A document type that supports reading from file. Conform to `ReadableDocument` to build a read-only document viewer, or combine with ``WritableDocument`` (via the ``Document`` protocol) for full read-write support. A readable document is a reference type so that SwiftUI can maintain a stable identity across updates. Use `@Observable` to enable per-property change tracking: @Observable final class MarkdownViewer: ReadableDocument { static let readableContentTypes: [UTType] = [.markdown] var attributedText = AttributedString() func reader(configuration: sending ReadConfiguration) -> sending FileWrapperDocumentReader<String> { FileWrapperDocumentReader(configuration) { fileWrapper in guard let data = fileWrapper.regularFileContents else { throw CocoaError(.fileReadCorruptFile) } return String(decoding: data, as: UTF8.self) } } @MainActor func apply(snapshot: sending String, previous: sending String?) async throws { attributedText = try AttributedString( markdown: snapshot ) } } Present a read-only document with ``DocumentGroup`` using the viewer initializer: DocumentGroup { document in MarkdownView(document: document) } makeReadableDocument: { configuration, context in MarkdownViewer() } Set `CFBundleTypeRole` to `Viewer` in your Info.plist for read-only document types.

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This type has no directly callable members in this snapshot. See the framework’s skipped declarations for unsupported APIs.

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