Following the apple documentation I am trying to set up a simple NSTextView
via its two constructor methods.
I am placing the below code inside the viewDidAppear
method of the view controller of the content view. textView is an instance of NSTextView
, frameRect is the frame of the content view.
The following Swift code works (gives me an editable textView with the text showing on the screen):
textView = NSTextView(frame: frameRect!)
self.view.addSubview(textView)
textView.textStorage?.appendAttributedString(NSAttributedString(string: "Hello"))
The following does NOT work (text view is not editable and no text shown on the screen):
var textStorage = NSTextStorage()
var layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)
var textContainer = NSTextContainer(containerSize: frameRect!.size)
layoutManager.addTextContainer(textContainer)
textView = NSTextView(frame: frameRect!, textContainer: textContainer)
textView.editable = true
textView.selectable = true
self.view.addSubview(textView)
textView.textStorage?.appendAttributedString(NSAttributedString(string: "Hello more complex"))
What am I doing wrong in the second example? I am trying to follow the example given in Apple's "Cocoa Text Architecture Guide" where they discuss setting up an NSTextView
by explicitly instantiating its web of helper objects.
You need to keep a reference to the NSTextStorage
variable you create. I'm not quite sure about the mechanics of it all, but it looks like the text view only keeps a weak reference to its text storage object. Once this object goes out of scope, it's no longer available to the text view. I guess this is in keeping with the MVC design pattern, where views (the NSTextView
in this case) are meant to be independent of their models (the NSTextStorage
object).
import Cocoa
@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
@IBOutlet weak var window: NSWindow!
var textView: NSTextView!
var textStorage: NSTextStorage! // STORE A REFERENCE
func applicationDidFinishLaunching(aNotification: NSNotification) {
var view = window.contentView as NSView
textStorage = NSTextStorage()
var layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)
var textContainer = NSTextContainer(containerSize: view.bounds.size)
layoutManager.addTextContainer(textContainer)
textView = NSTextView(frame: view.bounds, textContainer: textContainer)
textView.editable = true
textView.selectable = true
view.addSubview(textView)
textView.textStorage?.appendAttributedString(NSAttributedString(string: "Hello more complex"))
}
}