Correct release NSViewController embedded in subviews - swift

Question

I have a task to write a small app where various controllers must be embedded in default controller. All controllers stored in one storyboard.
Sample code of embedding controllers in subviews
if let id = getControllerId(pageIndex) { // get controller's storyboard id by segmented index
let storyBoard = NSStoryboard(name: "Main", bundle: nil)
let controller = storyBoard.instantiateControllerWithIdentifier(id) as! NSViewController
controller.view.translatesAutoresizingMaskIntoConstraints = false
if self.view.subviews.count > 0 {
let prevView = self.view.subviews[0]
prevView.removeFromSuperview() // here should be releasing previous controller
}
self.view.addSubview(controller.view)
// make all side constraints
let views = ["view": controller.view]
self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-(0)-[view]-(0)-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: views))
self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-(0)-[view]-(0)-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: views))
} else {
NSLog("ERROR: Unable get controller storyboard id for index \(pageIndex)")
}
And I noticed that embedded controller don't execute viewWillDisappear. I need this event for clearing observers and some other stuff.
I'm not sure it's correct way to show controllers as embedded in subviews, but i don't found any other solution.
I make sample project to test this situation
https://github.com/avvensis/embeddedviewcontrollers
Could anybody help me with this trouble?

Answer 1

viewWillDisappear wont execute as you dont hide anything.
You controller dies quickly after you create him. So step #1 is to hold a reference on it:
class ViewController: NSViewController {
// MARK: - Custom properties
let pageIds: [String] = ["redController", "yellowController", "greenController"]
var currentControler : NSViewController!
...
private func showEmbeddedController(pageIndex: Int) {
if let id = getControllerId(pageIndex) { // get controller's storyboard id by segmented index
let storyBoard = NSStoryboard(name: "Main", bundle: nil)
currentControler = storyBoard.instantiateControllerWithIdentifier(id) as! NSViewController
currentControler.view.translatesAutoresizingMaskIntoConstraints = false
if self.view.subviews.count > 0 {
let prevView = self.view.subviews[0]
prevView.removeFromSuperview() // here should be releasing previous controller
}
self.view.addSubview(currentControler.view)
// make all side constraints
let views = ["view": currentControler.view]
self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("|-(0)-[view]-(0)-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: views))
self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-(0)-[view]-(0)-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: views))
} else {
NSLog("ERROR: Unable get controller storyboard id for index \(pageIndex)")
}
}
}
Then just have deinit method in your base controller:
class EmbeddedViewController: NSViewController {
....
deinit {
print("DEBUG: \(self.className) deinit")
}
}