CODEWITHSUNDEEP
swiftmacoscocoadocument
Displaced Hoser
Displaced Hoser

Reputation: 911

Ambiguous reference to member 'close()'

I am trying to create an application that will allow a user to cycle through next/previous text document files in a folder, the way photo-viewing apps will often allow next/previous picture view. It seems to me so far that the most effective way to do this is to replace the document in the currently open window. The edited answer to my previous question on the topic suggests that this is indeed possible. I want to be able to use the document architecture for opening and saving; I don't want to have to generalize the framework, I'm trying to keep it simple. I tried to use the code recommended in the previous question as follows: 

let prevDocument = windowController.document
let newDocument = Document(contentsOf: newURL, ofType: myDocumentType) // add do-catch
NSDocumentController.shared.addDocument(newDocument);
newDocument.addWindowController(windowController)
prevDocument.close()

But when I do this, the prevDocument.close() command gives me the odd error "Ambiguous reference to member 'close()'". Another thread tells me that "This kind of error appears when there's more than one variable/method with the same name". OK, but which ones, and how do I fix it? Underneath the "ambiguous reference" error I get two messages: "Found this candidate (Foundation.Stream)" and "Found this candidate (AppKit.NSBezierPath)". A brief look at the docs for Foundation.Stream and NSBezierPath suggests that Foundation.Stream and not NSBezierPath is what I'm trying to work with, but I have no idea how to tell the system that (or why NSBezierPath would be involved in the first place).

Upvotes: 0

Views: 61

Answers (1)

Seb Jachec
Seb Jachec

Reputation: 3061

The document property of an NSWindowController has type AnyObject?, hence why there's no close method and the compiler struggles to figure out what type of object it could be, such that it could have a close method.

Clicking through to the documentation of the document property in Xcode (ctrl-cmd click) shows a comment that the document property is usually of type NSDocument, which does have a close method. Typecasting is worth a try:

guard let prevDocument = windowController.document as? NSDocument else {
    // ...
}

// Rest of your code

Alternatively, if you can guarantee that only one document at a time will be managed by your application:

guard let previousDocument = NSDocumentController.shared.documents.first else {
    // ...
    return
}

// Rest of your code

Upvotes: 1

Related Questions