The SwiftUI document architecture revolves around three main components: DocumentGroup, FileDocument, and FileDocumentView. Let's dive into each of these components to gain a deeper understanding:

1. DocumentGroup:
2. DocumentGroup is a container that manages the lifecycle and presentation of documents in your app. It acts as the entry point for your app's document-based functionality, allowing users to create, open, and save documents. DocumentGroup also provides a consistent user interface for document management, such as displaying document thumbnails, managing multiple document instances, and supporting document interactions like duplication or deletion.
3. FileDocument:
4. FileDocument is a protocol that represents a document's data model. By conforming to the FileDocument protocol, you define the structure and behavior of your document's data. FileDocument enables seamless encoding and decoding of document data to and from file formats, making it easy to save and load documents.
5. FileDocumentView:
6. FileDocumentView is a SwiftUI view that represents the visual representation of a document. It displays the content of the document, handles user interactions, and allows users to modify the document's data. FileDocumentView interacts with the underlying FileDocument to update the document's state and ensure data consistency.

Building Apps with SwiftUI Document Architecture:

To leverage the SwiftUI document architecture effectively, follow these general steps:

1. Define the FileDocument:
2. Create a custom data model by conforming to the FileDocument protocol. Define the necessary properties and methods to represent the document's data and its encoding and decoding requirements. This allows your app to manage document data seamlessly.
3. Create the FileDocumentView:
4. Build a SwiftUI view that represents the visual representation of the document. Implement the necessary views and controls to display and modify the document's data. Interact with the FileDocument to update the document state and handle user actions.
5. Implement the DocumentGroup:
6. Set up a DocumentGroup in your app's entry point, such as the @main struct. Configure the DocumentGroup to handle document creation, opening, and saving. Specify the FileDocument type to be used, ensuring that your app's data model is associated with the appropriate documents.
7. Customize Document Behavior:
8. Customize the behavior of your documents by implementing optional methods in the FileDocument protocol. These methods allow you to handle document updates, manage autosaving, and perform additional operations based on document lifecycle events.