Saving with NSDocument in a Second ViewController - swift

Question

I am trying to simply save using NSDocument to a rtf. The code works fine but when I try to save to a view controller that isn't the initial child to the window controller it throws an error from a modal saying 'The document “” could not be saved as “”.'
How can I save the file to the Second View Controller?
Window Controller
|
Login View Controller
| |
SidebarViewContoller ViewController1
|
TableViewController 2 Replaces VC1
Save TextView in this VC
I want to be able to write data into My NSDocument from the textView in ViewController2 and save it to the desktop
Just like you would for instance in Pages
Here is the code
// Document.swift
class Document: NSDocument {
var text = NSAttributedString()
var documentViewController: DocumentViewController? {
return windowControllers[0].contentViewController as? DocumentViewController
}
override init() {
super.init()
// Add your subclass-specific initialization here.
}
override class var autosavesInPlace: Bool {
return true
}
override func makeWindowControllers() {
// Returns the Storyboard that contains your Document window.
let storyboard = NSStoryboard(name: NSStoryboard.Name("Main"), bundle: nil)
let windowController = storyboard.instantiateController(withIdentifier: NSStoryboard.SceneIdentifier("Document Window Controller")) as! NSWindowController
self.addWindowController(windowController)
}
override func data(ofType typeName: String) throws -> Data {
// Save the text view contents to disk
if let textView = documentViewController?.textView {
let rangeLength = textView.string.count
textView.breakUndoCoalescing()
let textRange = NSRange(location: 0, length: rangeLength)
if let contents = textView.rtf(from: textRange) {
return contents
}
}
throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)
}
override func read(from data: Data, ofType typeName: String) throws {
if let contents = NSAttributedString(rtf: data, documentAttributes: nil) {
text = contents
}
}
//SecondViewController
override func viewDidAppear() {
let document = self.view.window?.windowController?.document as! Document
textView.textStorage?.setAttributedString(document.text)
}

Answer 1

The way you have things set up in your app, you are not going to be able to put an entire NSDocument's contents in a text view. Suppose you have 10 items in the table view and selecting an item fills the text view with some text. You're not going to be able to have a NSDocument for each of the 10 table view items inside a single document.
What you are going to have to do is create a data structure that represents a text file. Think of a chapter in a book or a scene in a screenplay. In your NSDocument subclass, you will have an array of these data structures. When you save the document, you will save it as a file wrapper, which is a directory of files that looks like a single file in the Finder. There will be one text file in the file wrapper for each item in the table view. Refer to the following article to learn more about file wrappers:
Working with File Wrappers in Swift
Now what you want to know is how to fill the text view when the table view selection changes. This is painful to do with Mac storyboards because the table view's controller and the text view's controller are separate scenes. Implement the delegate method tableViewSelectionDidChange in the view controller for the table view. Use the parent property to get the split view controller. Use the split view controller to get the text view's controller. Pass the selected row to the text view's controller and use that to get the right text file to display in the text view.
The split view controller should store a reference to the NSDocument. Use the parent property to access the split view controller from the text view's controller. With access to the split view controller, you can access the document to fill the text view with the contents of the text file corresponding to the selected item in the table view.