Build a desktop-class iPad app

navigationItem.style = .editor

navigationItem.backAction = UIAction(…)

let properties = UIDocumentProperties(url: document.fileURL)

if let itemProvider = NSItemProvider(contentsOf: document.fileURL) {
    properties.dragItemsProvider = { _ in
        [UIDragItem(itemProvider: itemProvider)]
    }
    properties.activityViewControllerProvider = {
        UIActivityViewController(activityItems: [itemProvider], applicationActivities: nil)
    }
}

navigationItem.documentProperties = properties

override func viewDidLoad() {
    navigationItem.renameDelegate = self
}

func navigationItem(_ navigationItem: UINavigationItem, didEndRenamingWith title: String) {
    // Rename document using methods appropriate to the app’s data model
}

override func duplicate(_ sender: Any?) {
    // Duplicate document
}

override func move(_ sender: Any?) {
    // Move document
}

func didOpenDocument() {
    ...
    navigationItem.titleMenuProvider = { [unowned self] suggested in
        var children = suggested

        ...

        return UIMenu(children: children)
    }
}

func didOpenDocument() {
    ...
    navigationItem.titleMenuProvider = { [unowned self] suggested in
        var children = suggested
        children += [
            UIMenu(title: "Export…", 
                   image: UIImage(systemName: "arrow.up.forward.square"), 
                   children: [
                UIAction(title: "HTML", image: UIImage(systemName: "safari")) { ... },
                UIAction(title: "PDF", image: UIImage(systemName: "doc")) { ... }
            ])
        ]
        return UIMenu(children: children)
    }
}

navigationItem.customizationIdentifier = "editorView"

UIBarButtonItem(title: "Sync Scrolling", ...).creatingFixedGroup()

UIBarButtonItem(title: "Add Link", ...).creatingOptionalGroup(customizationIdentifier: "addLink")

UIBarButtonItemGroup.optionalGroup(customizationIdentifier: "textFormat",
																	 isInDefaultCustomization: false,
																	 representativeItem: UIBarButtonItem(title: "Format", ...)
																	 items: [
																	      UIBarButtonItem(title: "Bold", ...),
																	      UIBarButtonItem(title: "Italics", ...),
																	      UIBarButtonItem(title: "Underline", ...),
																	 ])

sliderGroup.menuRepresentation = UIMenu(title: "Text Size",
                                        preferredElementSize: .small,
                                        children: [
    UIAction(title: "Decrease",
             image: UIImage(systemName: "minus.magnifyingglass"),
             attributes: .keepsMenuPresented) { ... },
    UIAction(title: "Reset",
             image: UIImage(systemName: "1.magnifyingglass"),
             attributes: .keepsMenuPresented) { ... },
    UIAction(title: "Increase",
             image: UIImage(systemName: "plus.magnifyingglass"),
             attributes: .keepsMenuPresented) { ... },
])

// Enable multiple selection
collectionView.allowsMultipleSelection = true

// Enable keyboard focus
collectionView.allowsFocus = true

// Allow keyboard focus to drive selection 
collectionView.selectionFollowsFocus = true

func collectionView(_ collectionView: UICollectionView, 
                    performPrimaryActionForItemAt indexPath: IndexPath) {
  
    // Scroll to the tapped element
    if let element = dataSource.itemIdentifier(for: indexPath) {
        delegate?.outline(self, didChoose: element)
    }
}

func collectionView(_ collectionView: UICollectionView, 
                      contextMenuConfigurationForItemsAt indexPaths: [IndexPath], 
                      point: CGPoint) -> UIContextMenuConfiguration? {

    if indexPaths.count == 0 {
        // Construct an empty space menu
    } 
    else if indexPaths.count == 1 {
        // Construct a single item menu
    } 
    else {
        // Construct a multi-item menu
    }
}

textView.isFindInteractionEnabled = true

func textView(_ textView: UITextView,
              editMenuForTextIn range: NSRange,
              suggestedActions: [UIMenuElement]) -> UIMenu? {
    
    if textView.selectedRange.length > 0 {
        let customActions = [ UIAction(title: "Hide", ... ) { ... } ]
        return UIMenu(children: customActions + suggestedActions)
    }
    
    return nil
}