Correct release NSViewController embedded in subviews

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?

Solution

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")
}

}