# activityViewController(_:dataTypeIdentifierForActivityType:) For items that are provided as data, returns the UTI for the item. ``` optional func activityViewController(_ activityViewController: UIActivityViewController, dataTypeIdentifierForActivityType activityType: UIActivity.ActivityType?) -> String ``` ## Parameters `activityViewController` The activity view controller object requesting information about the data item. `activityType` The selected activity type; may be `nil`. ## Return Value The UTI for the item. ## Discussion Providing the UTI allows services to handle specific data types in appropriate ways, such as an email service formatting an image to display in-line. If you provide items as objects, implement this method to allow those services to better handle your data. To ensure that Mail can handle an attachment that uses your exported UTI, include the [UTExportedTypeDeclarations](https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html#//apple_ref/doc/plist/info/UTExportedTypeDeclarations) key in your app’s `Info.plist` file, describing the UTI and providing the MIME type for it. The following example shows how `public.jpeg` might be defined as an exported type (only the required keys are shown): ```objc UTExportedTypeDeclarations UTTypeIdentifier public.jpeg UTTypeConformsTo public.image public.data UTTypeTagSpecification com.apple.ostype JPEG public.filename-extension jpeg jpg public.mime-type image/jpeg ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)