Setting up a ViewController for a .xib view - ios

Question

I am neither an iOS developer, nor a swift developer, but please bear with me:
I am currently trying to implement a simple iOS app but I have difficulties understanding how exactly I am supposed to set up custom UIViews and ViewControllers for those UIViews.
I am using a UIScrollView that is containing items a little bit more complex than just images, thats what I use custom views for.
What I did was:
I created a .xib file, the view itself. I added some elements (here it is only a textfield, for simplicity's sake).
I created a cocoa touch class "CustomView" that inherits from UIView and set my view up to be of that class (inside the class I just set up elements and such).
Now I want a ViewController that controls the class whenever it is rendered (for example reacting to the changing textField).
I cant manage everything from my main ViewController, because it would get too big (e.g. 3 scrollViews * 5 subviews that need to be managed).
I want a solution that uses ViewControllers for each subview (in case they themselves will have subviews, too).
How do I do that?
Do I need to add some sort of childViewController?
I really am at loss, most of the blog posts and SO examples simply do not work and/or are outdated and I am unsure about whether or not I got the whole View - ViewController pattern wrong.

Answer 1

Let's say you have two view controllers, MainViewController and TableViewController. TableVC's main view is to be a subview of MainVC's main view. In addition, you wish to pass back to MainVC which cell was selected in TableVC.
A solution is (a) make TableVC be a child to MainVC and (b) make MainVC be a delegate for TableVC.
TableViewController:
protocol TableVCDelegate {
func cellSelected(sender: TableViewController)
}
class TableViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
// please note that you can do delegation differently,
// this way results in crashes if delegate is nil!
var delegate:TableVCDelegate! = nil
var someValue = ""
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
// set someValue to contents in the selected cell or it's data source
someValue = "Hello World!"
delegate.cellSelected(sender: self)
}
}
MainViewController:
class MainViewController: UIViewController, TableVCDelegate {
let tableVC = TableViewController()
override func viewDidLoad() {
// make tableVC be a child of this VC
addChild(tableVC)
tableVC.didMove(toParent: self)
tableVC.delegate = self
// position tableVC.view
tableVC.view.translatesAutoresizingMaskIntoConstraints = false
}
func cellSelected(sender: TableViewController) {
print(sender.someValue) // this should send "Hello World!" to the console
}
}
This is obviously untested code, but it is based on product code. This is meant to be a shell to help you get started.