Connect programmatically created view to IB - swift

Question

Following this answer, I managed to add half-modally presented ViewControllerB to ViewControllerA. However, in the example, ViewControllerA is just a red view. I would like to connect it to IB in order to customize it. I tried creating a view controller in IB of class ViewControllerB and connect one of its views to #IBOutlet var menuView: UIView! instead of creating menuView programmatically (as in the example). However, nil was found when adding menuView to the view as a subview. Any help would be great. Thanks!

Answer 1

A couple of observations:
In that example, there is a line that says:
let vc = ViewControllerB()
You could define this view controller’s view in a NIB and this would work fine. But if you’re using storyboards, replace that with ...
let vc = storyboard!.instantiateViewController(withIdentifier: “identifier")
... where identifier is some string that you supplied as the “Storyboard ID” in the “Identity inspector” in IB for that scene.
If this is being triggered by a button or something like that, you can also remove this gotoVCB in that sample, and just do the modal presentation right in IB like usual (e.g. control-dragging from the button to the next scene) and choosing “Present modally”. But you’d have to make sure that you configured all init methods, e.g.:
class ViewControllerB: UIViewController {
// used if you use NIBs or just call `init()`
override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
configure()
}
// used if you use storyboards
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
configure()
}
private func configure() {
modalPresentationStyle = .custom
transitioningDelegate = self
}
...
}
Unrelated to the immediate question, I might suggest splitting up that answer’s code into separate objects to prevent view controller “bloat”, with better separation of responsibilities between a transitioning delegate object, the animation controller, etc.
For example, maybe:
class ViewControllerB: UIViewController {
let customTransitioningDelegate = PopUpMenuTransitioningDelegate()
override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
configure()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
configure()
}
func configure() {
modalPresentationStyle = .custom
transitioningDelegate = customTransitioningDelegate
}
}
And
class PopUpMenuTransitioningDelegate: NSObject, UIViewControllerTransitioningDelegate {
func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return PopUpMenuAnimationController(transitionType: .presenting)
}
func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return PopUpMenuAnimationController(transitionType: .dismissing)
}
}
And
class PopUpMenuAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
enum TransitionType {
case presenting
case dismissing
}
let transitionType: TransitionType
init(transitionType: TransitionType) {
self.transitionType = transitionType
super.init()
}
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return 1
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
let containerView = transitionContext.containerView
guard let toVC = transitionContext.viewController(forKey: .to),
let fromVC = transitionContext.viewController(forKey: .from) else { return }
switch transitionType {
case .presenting:
containerView.addSubview(toVC.view)
var rect = fromVC.view.bounds
let menuHeight = fromVC.view.bounds.height / 2
rect.origin.y += fromVC.view.bounds.height
rect.size.height = menuHeight
toVC.view.frame = rect
toVC.view.alpha = 0
UIView.animate(withDuration: 0.4, delay: 0, options: [.curveEaseOut], animations: {
rect.origin.y = menuHeight
toVC.view.frame = rect
toVC.view.alpha = 1
}, completion: { _ in
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
})
case .dismissing:
UIView.animate(withDuration: 0.4, delay: 0, options: [.curveEaseOut], animations: {
var rect = fromVC.view.frame
rect.origin.y = toVC.view.bounds.height
fromVC.view.frame = rect
fromVC.view.alpha = 0
}, completion: { _ in
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
})
}
}
}
That decouples the transitioning delegate and animation controller from the view controller and lets you use this with other view controllers should you ever need to.
Note, I’m also a little more careful about the parameter to completeTransition, too. Once you start playing around with interactive transitions, you might support cancelable transitions.