Build better document-based apps

3:54 - Loading a document

override func load(fromContents contents: Any, ofType typeName: String?) throws {
    // Load your document from contents
    guard let data = contents as? Data,
          let text = String(data: data, encoding: .utf8) else {
        throw DocumentError.readError
    }
    self.text = text
}

4:08 - Saving a document

override func contents(forType typeName: String) throws -> Any {
    // Encode your document with an instance of NSData or NSFileWrapper
    guard let data = self.text?.data(using: .utf8) else {
        throw DocumentError.writeError
    }
    return data
}

4:34 - Manually saving and loading a document

override func save(to url: URL,
                   for saveOperation: UIDocument.SaveOperation,
                   completionHandler: ((Bool) -> Void)? = nil) {
    self.performAsynchronousFileAccess {
        // Set up file coordination and write file to URL
   }
}

override func read(from url: URL) throws {
    // Set up file coordination and read file from URL
}

5:08 - Defining document that require saving

class Document: UIDocument {
    var text: String? {
        didSet {
            if oldValue != nil && oldValue != text {
                self.updateChangeCount(.done)
            }
        }
    }
}

6:30 - Updating the view hierarchy for a document

override func documentDidOpen() {
    configureViewForCurrentDocument()
}

override func viewDidLoad() {
    super.viewDidLoad()
    configureViewForCurrentDocument()
}

func configureViewForCurrentDocument() {
    guard let document = markdownDocument,
          !document.documentState.contains(.closed)
            && isViewLoaded else { return }
    // Configure views for document
}

7:17 - Updating navigation items for a document

override func navigationItemDidUpdate() {
    // Customize navigation item
}

8:01 - Manually opening a document

documentController.openDocument { success in
    if success {
        self.present(documentController, animated: true)
    }
}

9:20 - Renaming a UIDocument without UIDocumentViewController

navigationItem.renameDelegate = document