Transferable and Content Sharing Reference

Reference for the CoreTransferable framework and the SwiftUI surfaces that use it: drag and drop, copy and paste, and ShareLink. It covers making custom types transferable, choosing a transfer representation, declaring UTTypes, and bridging to UIKit.

When to Use This Reference

Use this reference when:

• Making a custom model type draggable or shareable
• Implementing drag and drop with .draggable and .dropDestination
• Adding copy and paste with .copyable, .pasteDestination, or PasteButton
• Sharing content with ShareLink
• Choosing between CodableRepresentation, DataRepresentation, FileRepresentation, and ProxyRepresentation
• Declaring custom UTTypes for app-specific formats
• Bridging Transferable types to UIKit's NSItemProvider

Example Prompts

Questions you can ask your assistant that will draw from this reference:

• "How do I make my model draggable in SwiftUI?"
• "What's the difference between DataRepresentation and FileRepresentation?"
• "How do I add a ShareLink with a custom preview?"
• "Why does my drag and drop work in my app but not across apps?"
• "How do I declare a custom UTType?"
• "How do I accept dropped files in my view?"
• "How do I add copy and paste support for my custom type?"
• "How do file promises work when dragging to Finder?"
• "Why does my drop target stop working when the window resizes mid-drag?"

What's Covered

• Choosing a representation – A decision tree that picks the TransferRepresentation for your data type
• CodableRepresentation – Codable models, with optional custom encoders
• DataRepresentation – Custom binary formats with import and export closures
• FileRepresentation – Large on-disk files and the temporary-file lifecycle
• ProxyRepresentation – Fallback representations, and why declaration order matters
• Export controls – Combining representations, conditional export, visibility, suggested file names
• ShareLink and SharePreview – SwiftUI sharing with custom previews
• Drag and drop – .draggable, .dropDestination, custom drag previews, multiple item types
• Clipboard – .copyable, .pasteDestination, .cuttable, PasteButton, and their platform differences
• UTType declarations – System types, custom types, Info.plist entries, UTType.markdown and UTType(identifier:allowUndeclared:) (iOS 27)
• UIKit bridging – NSItemProvider.loadTransferable, UIActivityViewController
• Promised files – NSFilePromiseProvider and NSFilePromiseReceiver for drags to Finder on the Mac
• Drop targets during reflow – Keeping drop handling correct when the window resizes mid-drag
• Troubleshooting – A table of common errors and their fixes

Key Patterns

Making a Type Shareable and Draggable

extension UTType {
    static var recipe: UTType { UTType(exportedAs: "com.myapp.recipe") }
}

struct Recipe: Codable, Transferable {
    var title: String
    var ingredients: [String]

    static var transferRepresentation: some TransferRepresentation {
        CodableRepresentation(contentType: .recipe)
        ProxyRepresentation(exporting: \.title)  // Fallback: plain text
    }
}

ShareLink with a Preview

ShareLink(
    item: recipe,
    preview: SharePreview(recipe.title, image: recipe.heroImage)
)

Drag and Drop

Text(recipe.title)
    .draggable(recipe)

Color.clear
    .frame(width: 200, height: 200)
    .dropDestination(for: Recipe.self) { recipes, location in
        guard let recipe = recipes.first else { return false }
        self.droppedRecipe = recipe
        return true
    }

Documentation Scope

This page documents the transferable-ref skill in the axiom-swift suite. Most of what it covers needs iOS 16; the .copyable, .pasteDestination, and .cuttable modifiers need iOS 27 on iPhone and iPad, and macOS 13 on the Mac.

• For photo picking and library access, see photo-library-ref
• For gesture handling (taps, drag gesture state, composition), see SwiftUI Gestures
• For sharing App Intents entities through Transferable, see app-intents-ref

Related

• codable – The Codable patterns that CodableRepresentation builds on
• swiftui-26-ref – Multi-item and container-based dragging, new in iOS 27 and macOS 26