October 24th, 2018
If you create a document-based app project in Xcode, select the app target in the project editor, and click the Info button, you will see sections for imported and exported UTIs. If you have any of the following questions:
Keep reading because this articles answers those questions.
A UTI is a Uniform Type Identifier that uniquely identifies a file type. Apple has a list of system-declared UTIs, but it’s not being actively maintained. For example a plain text file has the UTI
public.plain-text. Most common file types have
public at the start of their UTIs.
If you create a new file type, you must create a UTI for it. The UTI should take the form
Use imported UTIs when your app edits file types that it doesn’t own. Suppose you’re developing an image editor. Your image editor edits image files in multiple file formats, such as PNG, JPEG, and TIFF. You would add an imported UTI for each file type the image editor can edit.
Use an exported UTI for any file types your app owns. When you create a new file type for your app’s documents, your app owns that file type, and you should create an exported UTI for the file type. The exported UTI lets the operating system and other apps know about the new file type.