iOS routing viewDidAppear to child view controller

Question

I'm adding a child view controller to a parent view controller, and everything works as expected, except that child view controller isn't having its usual callbacks triggered. eg, things like viewWillAppear(animated) is never called. I looked into it and thought it may be because I wasn't calling willMoveToParentViewController and didMoveToParentViewController on the child view controller before and after adding it to the parent, respectively. Unfortunately, fixing that has made no difference. Does anyone know how I can wire this up so that when I do addChildViewController and removeChildViewController the regular callbacks are triggered? After adding the childViewController, I also add its view as a subview to the parent view controller's view. At neither point (addChildViewController & addSubview) does the child view controller's viewWillAppear(animated), etc methods get called...

Nick

Answer 1

Chourobin answer in Swift:

override var shouldAutomaticallyForwardAppearanceMethods: Bool {
    return false
}

override func viewWillAppear(_ animated: Bool) {
    self.childViewControllers[self.segmentView.selectedSegmentIndex].beginAppearanceTransition(true, animated: animated)
}

override func viewDidAppear(_ animated: Bool) {
    self.childViewControllers[self.segmentView.selectedSegmentIndex].endAppearanceTransition()
}

override func viewWillDisappear(_ animated: Bool) {
    self.childViewControllers[self.segmentView.selectedSegmentIndex].beginAppearanceTransition(false, animated: animated)
}

override func viewDidDisappear(_ animated: Bool) {
    self.childViewControllers[self.segmentView.selectedSegmentIndex].endAppearanceTransition()
}

_{P.S. As I am not keeping the reference to a child VC as a property or a variable. I preferring to access it using the currently selected segment index. SegmentView is a third party UISegmentControl.}