Is it possible to have embed segue/containing view in a scrollview with code?

Question

On an iPhone project I'm using Xcode storyboard to embed a few containing views in a main scroll view. I've heard containing view is also an "embed segue". Now I don't necessarily have to embed other child controllers, I could have just created custom views and have the original child controllers' logic in those custom subviews. (I think I'm just going to do that after posting here, because it seems easier.) But I've already done the code and want to know how easy or hard it is to stay with it.

Because scroll view content is greater than the main screen bounds, it's harder to layout the container view in storyboard. I can think of three ways to solve it. I can either

1. Drag the scroll view up and down and put my container views there.
2. Just drag some view in the scroll view, and then resize the frame in the main controller's viewDidLoad. (And if I'm using auto layout then I would add auto layout there) But just seems to defy the advantage of having storyboard and embed segue in the first place. But it seems easier than #3 if I have to interact with child view controllers.
3. Forget storyboard and just write a Containing controller logic (as described in WWDC 2012 video Implementing UIViewController Containment) but this appears to be complicated.

Is there a way to create embed segue in Xcode, but NOT putting it in but to do something like a "manual segue" as with other view transitions? I wouldn't be able to see the layout in storyboard but at least it'll be easier than #3 and I don't have to drag up and down like #2 which seems silly.

Answer 1

Here are the helper functions I use to programmatically embed a child view controller in a view.

struct MyChildViewController {
  static func embed(
    viewControllerId: String,
    storyboardName: String,
    containerViewController: UIViewController,
    containerView: UIView) -> UIViewController? {

    guard let viewController = initViewController(viewControllerId, storyboardName: storyboardName)
      else { return nil }

    containerViewController.addChildViewController(viewController)
    containerView.addSubview(viewController.view)

    viewController.view.translatesAutoresizingMaskIntoConstraints = false

    MyConstraints.fillParent(
      viewController.view, parentView: containerView, margin: 0, vertically: true)

    MyConstraints.fillParent(
      viewController.view, parentView: containerView, margin: 0, vertically: false)

    viewController.didMoveToParentViewController(containerViewController)

    return viewController
  }

  static func initViewController(viewControllerId: String, storyboardName: String) -> UIViewController? {
    let storyboard = UIStoryboard(name: storyboardName, bundle: NSBundle.mainBundle())
    return storyboard.instantiateViewControllerWithIdentifier(viewControllerId)
  }
}

struct MyConstraints {
  static func fillParent(view: UIView, parentView: UIView, margin: CGFloat = 0,
    vertically: Bool) -> [NSLayoutConstraint] {

    var marginFormat = ""

    if margin != 0 {
      marginFormat = "-\(margin)-"
    }

    var format = "|\(marginFormat)[view]\(marginFormat)|"

    if vertically {
      format = "V:" + format
    }

    let constraints = NSLayoutConstraint.constraintsWithVisualFormat(format,
      options: [], metrics: nil,
      views: ["view": view])

    parentView.addConstraints(constraints)

    return constraints
  }
}

Usage:

let childWiewController = MyChildViewController.embed("MyViewControllerId", storyboardName: "MyStoryboardName", containerViewController: containerViewController, containerView: containerView)

Where:

• "MyViewControllerId" - the storyboard ID of the child view controller that will be embedded.
• "MyStoryboardName" - the name of the storyboard file with embedded view controller.
• containerView - the view in your container view controller that will have the child view controller embedded.

Answer 2

I understand that the WWDC has an hour of video on it. But if you have watched any of their other videos it should become quite clear that time does not directly relate to complexity. This is how you use a container (or a child sub view controller) programmatically:

[self addChildViewController:child];        // 1
[self.view addSubview:child.view];          // 2
[child didMoveToParentViewController:self]; // 3

Pretty simple and only two extra lines of code compared to adding a subview. As you said, there are storyboard solutions but depending on your complexity, doing this through code may be easier. It really comes down to your preference though.

If you intend to animate adding the view, you should make the last call to didMoveToParentViewController in the completion block (i.e. after the animation has been completed).